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Charmant, Jonathan Paul Henry. "Reactivity of the #mu#3-benzyne ligand towards small organic molecules." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238905.
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Soules, Régis. "Proprietes cooperatives de complexes polymetalliques des ligands squarate et thiosquarate." Toulouse 3, 1987. http://www.theses.fr/1987TOU30178.
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Etude de l'emploi d'un coordinat assembleur qui puisse par coordination avec le centre metallique utilise (metaux de transition du groupe viii) aboutir a un agencement a une dimension des motifs moleculaires par empilement d'entites monomeres ou par formation de chaines. Par utilisation du coordinat squarate sous ses formes oxygenees et soufrees, obtention d'un certain nombre de complexes de pt, pd, ni et cu repondant aux criteres fixes. Etude des structures de ces composes, de leurs proprietes physiques et de la relation structure-propriete. La nature du coordinat comme le caractere specifique de l'arrangement structural ont ete discutes pour une approche de la comprehension de la nature de ces proprietes physiques
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Ashoka, Sahadevan Suchithra. "Anilate-based molecular building blocks for metal-organic frameworks and molecular conductors Conducting Anilate-Based Mixed-Valence Fe(II)Fe(III) Coordination Polymer: Small-Polaron Hopping Model for Oxalate-Type Fe(II)Fe(III) 2D Networks Nanosheets of Two-Dimensional Neutral Coordination Polymers Based on Near-Infrared-Emitting Lanthanides and a Chlorocyananilate Ligand." Thesis, Angers, 2019. http://bu.univ-angers.fr/Contact.
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Ce travail porte sur la synthèse et la caractérisation de matériaux moléculaires fonctionnels basés sur la molécule anilate et présentant des propriétés de conductivité, de magnétisme et de luminescence. Les anilates sont des dérivés de la 2,5-dihydroxy-1,4-benzoquinone substitués en positions 3 et 6 par une variété d’éléments (H, F, Cl, Br, I, CN, etc). Parmi eux, le seul composé hétérosubstitué ClCNAn2- a été choisi pour préparer une nouvelle famille de polymères de coordination bidimensionnels (PC 2D) avec des métaux de transition ou des ions lanthanides : i) un PC à valence mixte FeIIFeIII, de formule [TAG][FeIIFeIII(ClCNAn)3], contient pour la première fois le cation triaminoguanidinium dans un réseau de coordination.ii) Des PC basés sur le ligand ClCNAn2- et des ions lanthanides émettant dans le proche infrarouge (YbIII, NdIII, ErIII). Ces composés ont été exfoliés en monocouches, et des études de photoluminescence ont été menées à la fois sur les cristaux et les monocouches. iii) Une famille de PC hétéroleptiques basés sur des ions lanthanides et sur deux types de ligands pontants, le ligand ClCNAn2- et des ligands de type carboxylates (DOBDC et F4-BDC). iv) Une famille de PC basés sur des ions DyIII ont été préparés afin d’étudier leur propriétés magnétiques. v) Finalement, la capacité des ligands anilates à se combiner à des conducteurs moléculaires basés sur le BEDT-TTF a été démontrée à travers la synthèse et l’électrocristallisation de semiconducteurs organiques et de conducteurs magnétiques hybrides avec l’anion [Fe(ClCNAn)3]3-This work reports on the design, synthesis and characterization of novel anilate-based functional molecular materials showing luminescent, magnetic and/or conducting properties. The family of anilate ligands comprises several derivatives obtained by introducing various substituents (H, F, Cl, Br, I, CN, etc.) at the 3 and 6 positions of the common 2,5-dihydroxy-1,4-benzoquinone framework. Among the anilate ligands, the only known heterosubstituted anilate with Cl/CN substituents at the 3,6 positions, ClCNAn2-, have been selected for preparing a novel family of 2D layered coordination polymers (2D CP) with both 3d metal ions and 4f lanthanide ions, through a general and straightforward synthetic strategy. i) Mixed-valence FeIIFeIII 2D CP, formulated as [TAG][FeIIFeIII(ClCNAn)3], containing, the tris(amino)-guanidinium (TAG) cation for the first time in such 2D networks has been synthesized and thoroughly characterized. ii) 2D CPs based on NIR-emitting lanthanides (YbIII, NdIII, ErIII) and the ClCNAn2- ligand, have been prepared and characterized. These layered compounds were exfoliated to nanosheets, by sonication-assisted solution synthesis. Time-resolved photoluminescence studies performed on both the bulk and nanosheets are also highlighted. iii) Novel family of heteroleptic 2D CPs based on NIR-emitting lanthanides and mixed ligands (ClCNAn2- and carboxylate ligands (DOBDC and F4-BDC)), were prepared and characterized. vi) Novel family of 2D CPs based on DyIII and ClCNAn2- were prepared in order to investigate their magnetic properties. v) Furthermore, the ability of anilate ligands to work as components of BEDT-TTF- based molecular conductors have been demonstrated through the synthesis, via electrocrystallization technique. vi) П-d hybrid multifunctional paramagnetic molecular conductors BEDT-TTF and [Fe(ClCNAn)3]3-) were also studied
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Hui, Yu 1977. "Heterjunctions of small molecular weight organic semiconductors." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81540.
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Photodiodes made of small molecular weight organic semiconductors have been fabricated. The organic materials under investigation are p-type Copper phthalocyanine (CuPc) and n-type 3,4,9,10-perylenetetracarboxylic bisbenzimidazole (PTCBI). Current-voltage and capacitance-voltage measurements have been performed to evaluate the electrical properties of the organic photodiodes. Optical measurements including responsivity and temporal response have also been carried out. It has been found that device efficiency of the photodiodes is influenced by the thickness of organic layers as well as the device structures. It is believed that organic layer thickness is a strong function of materials' exciton diffusion lengths. The thickness of the organic layer employed in the fabricated photodiode is 100 A or less. However, the fabricated devices with thin organic layer showed poor performance in terms of saturation current and breakdown voltage. As a result, new device structures have been proposed to overcome the problems. Stacking structure double heterojunction (SDH) and novel comb-like structure single heterojunction (CSH) device configurations have shown a substantial improvement in both electrical and optical parameters. There is at least 3 times enhancement in photocurrent and 10 times increase in external quantum efficiency for photodiodes employing CSH device structure and 100 A organic layer. Improvements in saturation current and breakdown voltage have also been observed. In addition, responsivity measurements in CSH devices have yielded a 7 times improvement. Furthermore, the carrier lifetime of the photodiode is estimated to be around 1 microsecond from the temporal response measurements. The combined effect of thin organic layers and new device structures leads to an overall improvement in device performance.
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CIARAMELLI, CARLOTTA. "Synthesis and characterization of new small-molecule ligands of LPS binding proteins." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2015. http://hdl.handle.net/10281/77016.
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Lo scopo del presente lavoro è la progettazione, la sintesi e la caratterizzazione di nuove small molecules, attive come ligandi di LPS (lipopolisaccaridi)-binding proteins. Gli LPS, o endotossine batteriche, sono macromolecole anfifiliche ubiquitarie sulla membrana esterna dei batteri Gram-negativi. Le proteine che legano gli LPS studiate nel corso di questo progetto di tesi di dottorato appartengono a due categorie: le proteine batteriche di trasporto Lpt e il sistema recettoriale TLR4, che comprende anche i co-recettori LBP, CD14, MD2.
Le proteine Lpt, e in particolare la proteina LptC, sono responsabili del meccanismo di esportazione del LPS alla superficie cellulare, che è uno step fondamentale della via biosintetica dell’LPS. Pertanto, la biogenesi dell’LPS rappresenta un target ideale per lo sviluppo di nuovi antibiotici contro i batteri Gram-negativi. Inoltre, le strutture delle proteine Lpt sono state risolte, ma il meccanismo di trasporto è ancora da elucidare.
Nel presente lavoro di tesi sono stati utilizzate diverse tecniche per studiare l'interazione tra LPS e LptC, con particolare attenzione agli studi di interazione via NMR. Inoltre, un nuovo LPS fluorescente è stato prodotto ed è stato utilizzato come tool per studi di interazione LPS-LptC con tecniche di fluorescenza. Sono state anche sviluppate alcune nuove molecole sintetiche. Questi glicolipidi sono stati progettati e sintetizzati per ottenere ligandi di LptC e, in prospettiva, potenziali antibiotici contro i batteri Gram-negativi.
Il Toll-like receptor 4 (TLR4), il recettore dell'immunità innata, riconosce l’LPS aiutato da altre proteine (LBP, CD14 e MD-2) ed è responsabile dell'induzione della risposta infiammatoria. Molecole sintetiche in grado di modulare l'attività dei recettori dell’immunità innata sono un potente mezzo per studiare il sistema recettoriale TLR4 e hanno grande interesse farmacologico come adiuvanti vaccinali (agonisti), agenti antisepsi e anti-infiammatori (antagonisti).
L’attività biologica di glicolipidi con una funzione amminica (IAXO-102) come antagonisti del TLR4 è stata chiaramente dimostrata dal nostro gruppo di ricerca. La sintesi di molecole derivate da IAXO-102, che mantengano l'attività biologica del precursore, è stato un obiettivo di questo lavoro. In particolare, sono state portate a termine le sintesi di sonde fluorescenti, utilizzate per studi di interazione, derivati zwitterionici e molecole dimeriche. Nei nostri laboratori sono stati ottenuti anche antagonisti anionici del TLR4 con una struttura chimica più simile a Lipide A. Lo scopo di questo lavoro è stato valutare, tramite esperimenti NMR, la loro capacità di legare co-recettore dell'immunità innata MD-2.
Il carattere anfifilico degli analoghi sintetici del lipide A sintetizzati finora è spesso associato ad una bassa solubilità in acqua e a scarsa biodisponibilità. Invece, i composti attivi sul TLR4 di origine naturale hanno una migliore solubilità e biodisponibilità. La modifica chimica di queste strutture è molto utile per modulare l'attività biologica e per migliorare la specificità nei confronti del target. Di conseguenza, in una fase successiva di questo lavoro di tesi, è stata intrapresa la sintesi di nuove molecole con strutture chimiche ispirate ai modulatori naturali del TLR4. Recentemente è stato dimostrato che alcuni composti fenolici estratti da olio di oliva hanno una buona attività come antagonisti del TLR4. Pertanto, la sintesi di alcuni analoghi di queste molecole è stata eseguita per ottenere nuovi potenziali antagonisti del TLR4, con una migliore solubilità in acqua e una ridotta tossicità.The purpose of this work is the design, synthesis and characterization of new small molecules, active as ligands of two different lipopolysaccharide (LPS)-binding proteins. LPS, or bacterial endotoxin, is an amphiphilic macromolecule ubiquitous on the outer membrane of Gram-negative bacteria. The LPS binding proteins studied during this thesis project belong to two classes: the bacterial proteins of the Lpt transport machinery and the mammalian TLR4 receptor system, including the co-receptors LBP, CD14, MD-2. Lpt proteins, and in particular the protein LptC, are responsible for the export mechanism of LPS to the cell surface of Gram negative bacteria, which is a fundamental step of the LPS biosynthetic pathway. Therefore, the LPS biogenesis represents an ideal target for development of novel antibiotics against Gram-negative bacteria. Moreover, the structures of Lpt proteins have been elucidated, but very little is known about the mechanism of LPS transport. In this thesis work different techniques were used to study the interaction between LPS and LptC, particularly NMR binding studies. Moreover, a new fluorescent LPS was produced and it was used as a tool to perform LPS-LptC interaction studies with fluorescence techniques. Some new synthetic molecules were also developed during this thesis. Glycolipidic small molecules were designed and synthesized in order to obtain LptC ligands and, in perspective, potential antibiotics against Gram-negative bacteria. Toll-like receptor 4 (TLR4), the innate immunity receptor, recognizes LPS, helped by other proteins (LBP, CD14 and MD-2), and it is responsible for the induction of inflammatory responses. Synthetic small molecules able to modulate innate immunity receptors activity are a powerful mean to study the TLR4 receptor system and have great pharmacological interest as vaccine adjuvants (agonists), antisepsis and anti-inflammatory agents (antagonists). Antagonist activity on TLR4 receptor system of amino glycolipids (IAXO-102) was clearly demonstrated by our research group. The synthesis of molecules derived from IAXO-102 which retain the biological activity of the precursor was a target of this work. In particular, the synthesis of fluorescent probes, used for binding studies, zwitterionic derivatives and dimeric molecules were performed. Anionic TLR4 antagonists with a chemical structure more similar to Lipid A were also obtained in our labs. The aim of this work was the evaluation via NMR binding experiments of their ability to bind the innate immunity co-receptor MD-2. The amphiphilic character of the synthetic lipid A analogues synthesized so far is often associated with low water solubility and poor bioavailability. In this respect, the natural TLR4-active compounds have better solubility and bioavailability. The chemical modification of these structures is very helpful to modulate their biological activity and to enhance target specificity. Consequently, in a later stage of this work, the synthesis of new small molecules with chemical structures inspired to natural TLR4 modulators was pursued. Very recently it was found that some phenolic compounds from olive oil extracts presented a good activity as TLR4 antagonists. The synthesis of some analogues of these molecules was performed to obtain new potential TLR4 antagonists with better water solubility and reduced toxicity.
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Rooney, Timothy Patrick Christopher. "Development of small molecule inhibitors of the bromodomain-histone interaction." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:dfe22076-befc-4881-8433-b563a9329478.
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Bromodomains bind to acetylated lysine residues 1 to mediate a wide range of biological processes, including the assembly of transcriptional machinery at modified histones. This thesis describes the design of small molecule inhibitors of bromodomains, with particular focus on the bromodomain of CREBBP. A fragment based approach was employed to investigate bicyclic amides as acetyl lysine mimics. Initially the benzoxazinone scaffold (BNZ) 2 was shown to be a novel, ligand efficient bromodomain inhibitor. Structure based elaboration of the BNZ scaffold was employed to direct substitutions towards the region of CREBBP with greatest variability compared to other bromodomains. Ultimately, the compounds in this series were limited to micromolar affinity for CREBBP, but provided useful structure activity relationships. Subsequently the dihydroquinoxalinone scaffold (DHQN) 3 was also shown to be a novel acetyl lysine mimic. Attachment of the optimum side group identified in the BNZ series led to the discovery of the first sub micromolar inhibitor of CREBBP. A co crystal structure with CREBBP revealed that the side group of this compound bound in a newly identified induced fit pocket, mediated by a cation π interaction. A combination of structural, functional and computational studies confirmed that the cation π interaction contributed significantly towards the binding affinity of these ligands. Further work to elaborate the DHQN core, or develop an alternative acetyl lysine mimic into a CREBBP inhibitor, did not lead to an improvement. However, the optimum compound 4 was shown to displace CREBBP from chromatin in a cell based assay. Overall, cyclic amide based fragments were developed as CREBBP inhibitors, providing some of the first bromodomain ligands with nanomolar affinity outside of the BET family. In the process, key structural information about binding of ligands to CREBBP was revealed. Compound 4 provides a tool with which to study the biological implications of aberrant CREBBP activity and to investigate the therapeutic potential of bromodomain inhibition.
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Kueh, Alona Swee Hua. "Molecular imprinting of small, poorly functionalised organic compounds." The University of Waikato, 2008. http://hdl.handle.net/10289/2264.
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Molecularly imprinted polymers (MIPs) have been compared to natural antibodies in that they can specifically bind target compounds in a similar way that antibodies specifically bind to an antigen. The attraction of the MIPs technology is the ease of creating binding elements which are relatively cheap compared with the process of isolating natural antibodies. In this research monoterpenes, such as α-terpineol, were chosen to be the model compounds for investigating the molecular imprinting of small, poorly functionalised organic compounds. The conventional non-covalent approach was mainly used to synthesise these MIPs, but the sacrificial-spacer semi-covalent approach was also investigated. A less widely used method, porogen-imprinting - a variant of non-covalent imprinting - was adapted for α-terpineol. The latter novel terpene MIP appeared to specifically bind α-terpineol, by hydrogen bonding, so the polymer was characterised in detail. The main parameters which were altered for preparing non-covalent MIPs included the template (α-terpineol, (-)-menthol or trans-terpin); the functional monomer (methacrylic acid, 2-hydroxyethyl methacrylate, bilirubin and phenol [for the semi-covalent MIP]); the cross-linking monomer (ethylene glycol dimethacrylate, divinylbenzene and trimethylolpropane trimethacrylate); and also the polymerisation method (block or precipitation polymerisation). The binding specificity and cross-reactivity for all the polymers were tested using a liquid batch-binding setup. The batch-binding setup required the detection of analyte that was not bound in order to calculate by difference the fraction of analyte bound to the polymer. Initially the terpenes were to be detected by a colorimetric method; however attempts to make the method sensitive and reliable were not successful. In comparison, gas chromatography was more reliable for the detection of terpenes and was used for the experiments presented in this thesis. 1H-NMR studies of the interaction between α-terpineol and acetic acid (as a non-polymerisable analogue of methacrylic acid) were investigated as a basis for understanding the binding to the carboxyl functional group moiety employed in many of the non-covalent MIPs that were made. The interaction between (-)-menthol and phenol was also investigated because the phenol moiety was employed in the semi-covalent MIP. Only selected MIPs, which appeared to specifically bind the template, were physically characterised. This included optimising the batch-binding parameters, scanning electron microscopy imaging, surface area and pore radius analysis and in some cases Fourier transform-infrared spectroscopy of the polymers.
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Camuñas, i. Soler Joan. "Force-spectroscopy of small ligands binding to nucleic acids." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/286597.
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Single-molecule techniques allow to following biomolecular reactions with unprecedented resolution. Particularly, optical tweezers can be used to manipulate and apply forces to individual molecules tethered between plastic beads that are optically-trapped. Optical trapping is achieved by using highly focused laser beams that exert a gradient force onto the micrometer-sized dielectric particles that become confined close to the focal position of the laser. By specifically attaching the ends of the molecule under study to two optically-trapped beads, it is possible to manipulate and apply forces to an individual molecule. Typical experiments with optical tweezers consist in manipulating nucleic acids (DNA, RNA) or proteins one at a time. For instance DNA molecules can be stretched to measure its elastic properties, or unzipped to measure their base-pairing energies. Many small anticancer drugs target nucleic acids to exert their cytotoxic activity against cancer cells. To understand their mechanism of action it is important to know in which positions, how strong, and how fast do they bind to different specific sites in DNA. Single-molecule optical tweezers experiments can be used to unravel the binding thermodynamics and kinetics of many of these ligands, especially those difficult to characterize with bulk techniques. Thiocoraline is one of such drugs, and binds DNA through bis-intercalation. Experiments with optical tweezers show that the kinetics of intercalation are very slow (hours) and strongly force-dependent: force facilitates binding but slows down unbinding. Experiments performed in different conditions also reveal that the binding pathway proceeds through a mono-intercalated intermediate that causes the observed slow kinetics. In this sense, we present a three-state model that offers a theoretical framework from which the kinetic rates of the reaction can be extracted, and that could be useful to characterize other bis-intercalators. We also show that DNA unzipping experiments can be used to determine the preferred binding sequences of Thiocoraline, finding that it preferentially clamps CpG steps. This methodology is potentially very useful as it provides direct access to the preferred binding sites of small ligands due to its thermodynamic stability with one base pair resolution and without the requirement of restriction enzymes or radioactive labeling. This single-molecule footprinting technique is also adapted to a magnetic tweezers instrument in order to perform parallelized measurements. The fact that bis-intercalation does not modify the persistence length of dsDNA is also found in the pulling experiments. From the elasticity measurements, we also extract equilibrium quantitates of the interaction by using classic statistical models. This combination of DNA stretching and unzipping assays can also be used to follow how the anticancer agent Kahalalide F self-assembles and compacts DNA. Kahalalide F forms nanometric particles that are positively charged able to bind and condense DNA. The binding reaction shows to phases: an initial compaction of electrostatic origin, and its subsequent stiffening due to the hydrophobic collapse of the complex. The combination of quantitative force-spectroscopy measurements with AFM images of the complexes and other bulk tech- niques (DLS, EM) provides a consistent picture of the compaction and aggregation process. Modeling of the experiments provides the thermodynamic parameters of the interaction that are complemented with kinetic measurements. A simple technique to study ssDNA with optical tweezers is also presented and used to study how the stiffness of the polyanion affects the compaction process. We exploit this methodology to understand how the stiffness of the polyanion affects the compaction kinetics, and later on, we also show its utility to study the elasticity of ssDNA under varying ionic conditions. Finally, the utility of this methodology to study self-assembly and aggregation is explored with amyloidogenic peptides involved in neurodegenerative disorders.Les tècniques de molècula individual permeten seguir les reaccions biomoleculars amb una resolució sense precedents, proveint als científics d’una sèrie d’instruments per a mesurar magnituds físiques i investigar sistemes experimentals difícilment accessibles amb les tradicionals mesures en volum (és a dir a on les mesures es realitzen amb mols de reactiu). Particularment, les pinces òptiques permeten manipular i aplicar forces a molècules individuals i determinar-ne així les seves propietats elàstiques i termodinàmiques. L’atrapament òptic es basa en l’ús d’un feix làser focalitzat per exercir una força òptica a les microesferes (diàmetre ~ 3 µm), que queden confinades a prop del punt focal a causa de la conservació del moment lineal. Els experiments de micromanipulació es realitzen unint els extrems de la molècula que es vol estudiar a la superfícies de dues microesferes diferents, podent així aplicar forces a la molècula quan desplacem una microesfera respecte de l’altra. Per ancorar les molècules a la superfície de les microesferes s’utilitzen unions moleculars que tenen una alta a.nitat (p.ex. enllaç biotina-estreptavidina). Típicament els experiments amb pinces òptiques consisteixen en la micromanipulació d’àcids nucleics (ADN, ARN) o proteïnes de forma individual. Per exemple, una molècula d’ADN pot ésser estirada per a estudiar-ne les propietats elàstiques, o oberta mecànicament (separant les dues cadenes que formen la doble hèlix) per a mesurar les energies lliures d’aparellament entre bases. Un gran nombre d’agents anticancerígens tenen com a diana els àcids nucleics, a on s’hi uneixen afi i efecte de dur a terme la seva acció citotòxica (p. ex. interferint amb processos cel·lulars essencials com són la replicació, la transcripció o els mecanismes de reparació). Per entendre el seu mecanisme d’acció és important conéixer en quines posicions, amb quina a.nitat, i amb quina cinètica s’uneixen a diferents seqüències d’ADN. Els experiments de molècula individual amb pinces òptiques permeten determinar la termodinàmica i cinètica d’unió de molts d’aquests lligands, especialment aquells difícils de caracteritzar mitjançant mesures en volum. És per això que un dels objectius principals d’aquesta tesi ha estat aprofitar les potencialitats de les mesures de molècula individual per a caracteritzar pèptids anticancerígens poc solubles i difícils d’estudiar amb tècniques alternatives: des de la cinètica i termodinàmica d’unió, a l’especi.citat en seqüència i la cinètica d’autoacoblament.
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Savard, Didier. "The Versatile Chemistry of Aryl Substituted 1,2,4-triazole Ligands in Molecular Magnetism." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28677.
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The work presented in this thesis focuses on exploring the versatile chemistry of 4-aryl substituted 1,2,4-triazole derivatives. The ligands 4-(4'-nitrophenyl)-1,2,4-triazole (npt) and 4-(4'-carboxyphenyl)-1,2,4-triazole (Hcpt) were prepared following a modified known synthetic strategy. Reaction of either of these ligands with transition metal or lanthanide precursor salts resulted in two novel complexes, namely [FeII3(npt) 6(EtOH)4(H2O)2](ptol)6·4(EtOH) (1) and [DyIII4(mu3-OH) 2(mu3-O)2(cpt)6(MeOH)6(H 2O)]2·15,(MeOH) (5), and of five analogous compounds.
In the case of 1, the structural analyses and the magnetic properties indicated that the complex consisted of a linear trinuclear Spin Crossover FeII compound with a T1/2 of 148 K. For this complex, the SC-XRD analyses were performed at 100 and 181 K in order to characterize the structural changes occurring during the spin transition. For 5, the magnetic and structural data indicated that the complex was a dumbbell-shaped cubane dimer {DyIII 4}2 for which each cubane unit is a Single-Molecule Magnet with a small effective energy barrier.
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Hassan, Mohammad Rokib, and University of Lethbridge Faculty of Arts and Science. "Self-assembled molecular rods and squares with chalcogenadiazole framework ligands." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Chemistry and Biochemistry, c2010, 2010. http://hdl.handle.net/10133/2639.
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During the attempts to carry out Suzuki coupling reactions, the σ-bonded Pd−Caryl
benzochalcogenadiazolyl complexes trans-[ClPd(PPh3)2(C6H2BrN2E)] (E = S, Se) were
isolated. The corresponding bromo derivatives were also synthesized on purpose to
investigate their activity in Stille coupling reactions. A head-to-tail dimer trans-
[{ClPd(PPh3)(μ-C6H2BrN2Se)}2] was synthesized from the thermolysis of trans-
[ClPd(PPh3)2(C6H2BrN2Se)] in the presence of SeO2. The reduction potentials of the
mononuclear and dinuclear complexes were measured by cyclic voltammetry (CV) and
square wave voltammetry (SWV).
4,7-bis(2/4-pyridyl)benzochalcogenadiazole ligands were synthesized by Stille coupling
reactions and the 1,5-bis(4-pyridyl)naphthalene ligand was prepared by a Suzuki
coupling reaction. Reactions of the labile complex [BrRe(CO)4(NCMe)] with 4,7-bis(4-
pyridyl)benzochalcogenadiazole ligands in a 2:1 ratio afforded self-assembled molecular
rods [{ReBr(CO)4}2(μ-4,7-bis(4-pyridyl)benzochalcogenadiazoles)]. Palladium directed
molecular squares [(enPd)(μ-4,7-bis(4-pyridyl)benzochalcogenadiazole)]4[PF6]8 were
prepared by reactions of enPd(PF6)2 and 4,7-bis(4-pyridyl)benzochalco-genadiazoles in a
1:1 ratio. The optoelectronic properties of the ligands and the molecular rods were
investigated by CV and SWV, and by luminescence spectroscopy. The optical properties
of the square complexes were also studied by luminescence spectroscopy.xvii, 152 leaves : ill. (some col.) ; 29 cm
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CORSO, A. DAL. "TUMOR TARGETING VIA INTEGRIN LIGANDS: SYNTHESIS AND BIOLOGICAL EVALUATION OF RGD PEPTIDOMIMETIC-DRUG CONJUGATES." Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/331100.
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Peptides and peptidomimetics bearing the Arg-Gly-Asp peptide sequence have been demonstrated to bind with high affinity to αvβ3 Integrin, a heterodimeric transmembrane receptor overexpressed in several tumor cells. For these reasons, integrin ligands have been coupled to a variety of anticancer drugs, aiming at the selective delivery of the payload at the tumor site. This PhD work describes the conjugation of the peptidomimetic αvβ3 Integrin ligand cyclo[DKP-RGD] to different anticancer drugs (i.e. paclitaxel, daunorubicin and camptothecin) through peptide and disulfide linkers. The resulting small molecule-drug conjugates (SMDCs) are selective αvβ3 binders and are able to release the drug upon exposure to lysosomal enzymes (e.g. cysteine proteases) or intracellular reducing agents (e.g. glutathione). Cell proliferation assays against isogenic human cancer cells expressing αvβ3 at different levels (αvβ3 +/αvβ3 −) have been performed to evaluate the selective cytotoxic activity of RGD-based SMDCs against integrin-positive cancer cells. Fairly effective integrin targeting was displayed by the cyclo[DKP-RGD]-Val-Ala-PTX conjugate (compound 80), which was found to differentially inhibit proliferation in antigen-positive CCRF CEM αvβ3 versus antigen-negative isogenic CCRF-CEM cells. Next-generation cyclo[DKP-RGD]-Drug conjugates were prepared, aiming at improving the targeting effect shown by the cyclo[DKP-RGD]-Val-Ala-PTX conjugate as well as to deeply analyze the SMDC’s interactions with cancer cells.
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Lineberry, Aaron M. "Microwave-Assisted Synthesis of Small Ring Thia-Aza Mixed-Donor Ligands." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1310944928.
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Gäggeler, Kathrin. "Small molecular weight organic acids in the gas and aerosol phase /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18042.
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Turk, Benjamin E. (Benjamin Eisler) 1968. "The use of organic ligands to study the molecular mechanisms of angiogenesis and immunoregulation." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85243.
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Stückenschneider, Kai [Verfasser]. "Molecular Modeling of Adsorptive Interactions between Small Organic Molecules and Zeolites / Kai Stückenschneider." München : Verlag Dr. Hut, 2014. http://d-nb.info/1055863079/34.
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Habibi, Amirhossein. "Small Conjugated Push-Pull Molecular Donors for Organic Photovoltaics : characterization and Devices Optimization." Thesis, Angers, 2020. http://www.theses.fr/2020ANGE0008.
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Les cellules solaires organiques sont en général constituées de deux types de semi-conducteurs organiques, un donneur et un accepteur d’électrons. Ce travail porte sur l’évaluation de matériaux donneurs d’électron dérivés de molécules pi-conjuguées push-pull combinés à des dérivés du fullerène comme matériau accepteur. Cette thèse décrit d’abord la fabrication et l’optimisation des cellules photovoltaïques (PV) réalisées à partir du DPMA-T-DCV. Cette petite molécule conjuguée push-pull facilement accessible, présente de bonnes propriétés de transport de trous à l’état solide et est constituée d’un groupe électro-donneur diphénylméthylamine (DPMA), une unité thiophène (T) comme espaceur pi-conjugué et un groupe terminal électro-attracteur dicyanovinyle (DCV). Différents dispositifs ont été fabriqués (cellules bicouche ou à réseaux interpénétrés de structure conventionnelle ou inverse) puis optimisés en jouant sur l’épaisseur des couches, le ratio massique entre la molécule push-pull et le dérivé du fullerène sélectionné ainsi que sur le procédé de fabrication en solution ou sous vide. Des cellules àréseaux interpénétrés de structure conventionnelle avec des rendements de conversion PV supérieurs à 4% ont pu être élaborées par co évaporation du DPMA-T-DCV et de fullerène C60. 6De nouvelles molécules dérivées de DPMA-T-DCV, présentant un espaceur conjugué plus étendu ou un noyau sélénophène à la place de l’unité T et/ou un analogue carbazole plus rigide que le groupe DPMA, ont été évaluées en PV. Enfin, des multimères de push-pull ont également été testés dans des cellules à réseaux interpénétrés en présence de PC61BM ou PC71BM pour conduire à des rendements de photo-conversion de 3.4%Organic solar cells (OSCs) generally consist of two types of organic semiconductors, one electron acceptor and one electron donor. This PhD work deals with the evaluation of electron donor materials derived from piconjugated push-pull molecules combined with fullerene derivatives as acceptor materials. This thesis firstly describes the fabrication and optimization of photovoltaic (PV) cells made from the small DPMA-TDCVpush-pull conjugated molecule known for its good solid-state hole transport properties and constituted by a diphenylmethylamine (DPMA) electron-donating group, a thiophene (T) unit as pi-conjugated spacer and a terminal dicyanovinyl (DCV) electron-withdrawing group. Different devices have been manufactured such as bi-layer or bulk heterojunction (BHJ) OSCs with a conventional or inverted structure, and then optimized by adjusting the thickness of the layers, the weight ratio between the push-pull molecule and the selected fullerene derivative, and by using a solution or a vacuum deposition process as well. Conventional BHJ OSCs with PV conversion efficiencies greater than 4% could be achieved by co-evaporation of DPMA-T-DCV and fullerene C60. Then, new DPMA-T-DCV derivatives resulting from an extension of the pi-conjugated spacer or by replacing the T unit with a selenophene ring and/or the DPMA unit with its more rigid carbazole analogue, were assessed for PV. Finally, push-pull multimers were also tested in BHJ OSCs in the presence of PC61BM or PC71BM yielding photoconversion efficiencies up to 3.4%
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Holden, Daniel. "Understanding the diffusion of small gases in porous organic cages using molecular dynamics." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/14433/.
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The aim of this thesis was to accurately simulate the dynamic nature of known porous organic cage molecules, with a view to understanding the diffusion of different gases through their pore structures. Initial calculations showed that, due to their unique chemical structure, no ‘off-the-shelf’ force field (FF) was accurate enough to describe their dynamic motion. Therefore, a cage specific force field, (CSFF), was developed to be transferable across the first three cage systems, CC1-CC3. CSFF was subsequently used to rationalise the ‘on’/‘off’ porosity observed in two different polymorphs of CC1. A combination of computational simulations, including simulated surface area calculations, grand canonical Monte Carlo (GCMC) adsorption isotherms, and molecular dynamics (MD) simulations, for hydrogen and nitrogen in CC1α and CC1β, helped to confirm experimental results, as well as to provide further insight into why the polymorphism of CC1 alters the porosity of the molecule. In addition, CSFF was used to study the diffusion of a range of gases through crystalline CC3. Seven gases were chosen: hydrogen, nitrogen, carbon dioxide, methane, sulfur hexafluoride, krypton and xenon. A detailed understanding of the diffusivity within CC3 was accomplished by combining MD simulations with new methodologies and techniques, for example analysis of the dynamic connectivity. This helped to rationalise why CC3 showed good experimental uptake of gas, as well as highlighting potential separation capabilities. In summary, the development of CSFF has made it possible to simulate the diffusion of small gases through porous organic imine cages, and it has been shown that this diffusion is dependent on the relative size of the gas to the cage window, assuming that there is a suitable diffusion pathway. Using MD simulations, we have unlocked phenomena such as gas selectivity, rare-event hopping and the diffusion of gases to regions previously thought inaccessible. This has aided the rationalisation of existing experimental observations, and is a significant step forward for a priori prediction of porous organic cage systems, and their properties. This work has also led to new experiments that were prompted by my simulations. Finally, a new way to visualise the connectivity of a system has been introduced. This is achieved by monitoring how the surface area evolves with respect to time, during a MD simulation. This suggests how the pore channels of various systems, previously thought too small for gas adsorption, are actually suitable candidates for separations.
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Rajbanshi, Arbin. "Supramolecular interactions from small-molecule selectivity to molecular capsules." Diss., Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/3879.
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Zanella, S. "SYNTHESIS OF PEPTIDOMIMETIC LIGANDS TARGETING CELL-SURFACE RECEPTORS INVOLVED IN TUMOR ANGIOGENESIS." Doctoral thesis, Università degli Studi di Milano, 2017. http://hdl.handle.net/2434/473075.
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In the first part of the Thesis, the synthesis of different classes of peptidomimetics targeting integrin receptors is described. Both simple ligands and drug conjugates were synthesized and tested to assess their biological activity. In cancer therapy, peptides and peptidomimetics targeting integrins are employed as carriers to deliver cytotoxic drugs at the tumor site, taking advantage of integrin over-expression on the surface of tumor cells. Within this frame, synthetic efforts have been focused on the synthesis and on the conjugation to the cytotoxic agent paclitaxel of isoDGR-based integrin ligands to effect drug-targeting to integrin over-expressing tumor cells.
The second part of the Thesis deals with the vascular endothelial growth factor receptors and their ligands. In particular, the interaction of VEGF-C with VEGFRs has been considered, focusing the attention on the reason why this growth factor was considered a privileged candidate for the preparation of a small library of VEGFR-selective peptides. These peptides have been synthesized by introducing systematic modifications in the natural portion of the growth factor and evaluated as VEGFR binders and anti-angiogenic agents in vitro.
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Rohatgi, Priyanka. "Engineering Protein Molecular Switches To Regulate Gene Expression with Small Molecules." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/19852.
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Small molecule dependent molecular switches that control gene expression are important tool in understanding biological cellular processes and for regulating gene therapy. Nuclear receptors are ligand activated transcription factors that have been engineered to selectively respond to synthetic ligands and used as regulators of gene expression. In this work the retinoid X receptor (RXR), has been used to develop an inducible molecular switch with a near drug like compound LG335. Three RXR variants (Q275C; I310M; F313I), (I268A; I310A; F313A; L436F), (I268V; A272V; I310M; F313S; L436M) were created via site-directed mutagenesis and a structure based approach, such that they preferentially bind to the synthetic ligand LG335 and not its natural ligand, 9-cis retinoic acid. These variants show reverse ligand specificity as designed and have an EC50 for LG335 of 80 nM, 30 nM, 180 nM, respectively. The ligand binding domains of the RXR variants were fused to a yeast transcription factor Gal4 DNA binding domain. This modified chimeric fusion protein showed reverse response element specificity as designed and recognized the Gal4 response element instead of the RXR response element. The modified RXR protein did not heterodimerize with wild type RXR or with other nuclear receptor such as retinoic acid receptor. These RXR-based molecular switches were tested in retroviral vectors using firefly luciferase and green fluorescence protein and they maintain their inducible behavior with LG335. These experiments demonstrate the orthogonality of RXR variants and their possible use in regulating gene therapy.
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Schünemann, Christoph. "Organic Small Molecules: Correlation between Molecular Structure, Thin Film Growth, and Solar Cell Performance." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-105169.
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Das wesentliche Ziel dieser Doktorarbeit ist es, die Zusammenhänge zwischen der Struktur von kleinen organischen Molekülen, deren Anordnung in der Dünnschicht und der Effizienz organischer Solarzellen zu beleuchten. Die Kombination der komplementären Methoden spektroskopischer Ellipsometrie (VASE) und Röntgenstreuung, vor allem der unter streifendem Einfall (GIXRD), hat sich als sehr effiient für die Strukturuntersuchungen organischer Dünnschichten erwiesen. Zusammen geben sie einen detailreichen Einblick in die intermolekulare Anordnung, die Kristallinität, die molekulare Orientierung, die optischen Konstanten n und k und die Phasenseparation von organischen Schichten. Zusätzlich wird die Topografie der organischen Dünnschicht mit Rasterkraftmikroskopie untersucht. Der erste Fokus liegt auf der Analyse des Dünnschichtwachstums von Zink-Phthalocyanin (ZnPc) Einzelschichten. Für alle untersuchten Schichtdicken (5, 10, 25, 50 nm) und Substrattemperaturen (Tsub=30°C, 60°C, 90°C) zeigt ZnPc ein kristallines Schichtwachstum mit aufrecht stehenden ZnPc Molekülen. Um effiziente organische Solarzellen herzustellen, werden Donor- und Akzeptormoleküle üblicherweise koverdampft. Bei der Mischung von Donor- und Akzeptormolekülen bildet sich eine gewisse Phasenseparation aus, deren Form wesentlich für die Ladungsträgerextraktion entlang der Perkolationpfade ist. Der Ursprung dieser Phasenseparation wird innerhalb dieser Arbeit experimentell für ZnPc:C60 Absorber-Mischschichten untersucht. Um die Ausprägung der Phasenseparation zu variieren, werden verschiedene Tsub (30°C, 100°C, 140°C) und Mischverhältnisse (6:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:6) bei der Koverdampfung von ZnPc und C60 angewendet. GIXRD Messungen zeigen, dass hier der bevorzugte Kristallisationsprozess von C60 Molekülen die treibende Kraft für eine effiziente Phasenseparation ist. Solarzellen, die ZnPc:C60 Mischschichten mit verbesserter Phasenseparation enthalten (Tsub=140°C, 1:1), zeigen eine verbesserte Ladungsträgerextraktion und somit eine höhere Effizienz von 3,0% im Vergleich zu 2,5% für die entsprechende Referenzsolarzelle (Tsub=30°C, 1:1). Im zweiten Teil der Arbeit wird der Einfluss der Molekülorientierung auf die Dünnschichtabsorption beispielhaft an ZnPc und Diindenoperylen (DIP) untersucht. DIP und ZnPc Moleküle, die auf schwach wechselwirkenden Substraten wie Glas, SiO2, amorphen organischen Transportschichten oder C60 aufgedampft sind, zeigen eine eher stehende Orientierung innerhalb der Dünnschicht in Bezug zur Substratoberfläche. Im Gegensatz dazu führt die Abscheidung auf stark wechselwirkenden Substraten, wie z.B. einer Gold- oder Silberschicht oder 0.5 nm bis 2 nm dünnen PTCDA (3,4,9,10-Perylentetracarbonsäuredianhydrid) Templatschichten laut GIXRD und VASE Messungen dazu, dass sich die ZnPc und DIP Moleküle eher flach liegend orientieren. Dies führt zu einer wesentlich besseren Dünnschichtabsorption da das molekulare Übergangsdipolmoment jeweils innerhalb der Ebene des ZnPc und des DIP Moleküls liegt. Ein Einbetten von Gold- oder Silberzwischenschichten in organischen Solarzellen führt leider zu keinen klaren Abhängigkeiten, da die verbesserte Absorption durch die flach liegenden Moleküle von Mikrokavitäts- und plasmonischen Effekten überlagert wird. Ebenso wenig führte das Einfügen einer PTCDA-Zwischenschicht in organischen Solarzellen zum Erfolg, da hier Transportbarrieren den Effekt der verbesserten Absorption überlagern. Das letzte Kapitel konzentriert sich auf den Einfluss der Molekülstruktur auf das Dünnschichtwachstum am Beispiel von DIP und dessen Derivaten Ph4-DIP und P4-Ph4-DIP, Isoviolanthron und Bis-nFl-NTCDI (N,N-Bis(fluorene-2-yl)-naphthalenetetra-carboxylic Diimid) Derivaten. GIXRD Messungen belegen deutlich, dass die sterischen Behinderungen, hervorgerufen durch die Phenylringe (für Ph4-DIP und P4-Ph4-DIP) und Seitenketten (für Bis-nFl-NTCDI), ein amorphes Schichtwachstum induzieren. Im Vergleich sind die Dünnschichten von DIP und Bis-HFl-NTCDI kristallin. Bezüglich der Molekülorientierung und folglich der Absorption von DIP und dessen Derivaten kann ein starker Einfluss des Schichtwachstums beobachtet werden. In Solarzellen verhindert die Präsenz der Phenylringe eine effiziente Phasenseparation der Mischschichten aus (P4-)Ph4-DIP:C60, was zu einer verschlechterten Ladungsträgerextraktion und damit zu einem reduzierten Füllfaktor (FF) von 52% im Vergleich zu dem entsprechender DIP:C60 Solarzellen mit FF=62% führt Die Untersuchungen an der Bis-nFl-NTICDI Serie zeigen ein ähnliches Ergebnis: Auch hier zeichnen sich die amorphen Schichten aus Bis-nFl-NTCDI Molekülen mit Seitenketten durch schlechtere Transporteigenschaften aus als nanokristalline Bis-HFl-NTCDI SchichtenThe aim of this thesis is to demonstrate correlations between the molecular structure of small organic molecules, their arrangement in thin films, and the solar cell performance. For structure analysis of the organic thin films, the combination of variable angle spectroscopic ellipsometry (VASE) and grazing incidence X-ray diffraction (GIXRD) as complementary methods turned out to be a powerful combination. Using both methods, it is possible to obtain information about the crystallinity, crystallite size, intermolecular arrangement, mean molecular orientation, optical constants n and k, and phase separation within thin films. In addition, the topography of thin films is analyzed by atomic force microscopy. First, the thin film morphology of pristine zinc-phthalocyanine (ZnPc) films deposited at different substrate temperatures (Tsub=30°C, 60°C, 90°C) and for varying film thicknesses (5, 10, 25, 50 nm) is investigated. The ZnPc films grow highly crystalline with an upright standing molecular orientation with respect to the substrate surface for all investigated Tsub and all film thicknesses. In effcient organic solar cells, donor and acceptor molecules are commonly co-deposited to form a blend absorber film. This is usually accompanied by a certain phase separation between donor and acceptor molecules leads to a formation of percolation paths necessary to extract electrons and holes towards the electrodes. For ZnPc:C60 blends the origin of this phase separation process is analyzed by investigating different degrees of phase separation induced by film deposition at different Tsub (30°C, 100°C, 140°C) and for different blend ratios (6:1, ... , 1:6 (vol%)). GIXRD measurements indicate that the preferred crystallization of C60 is the driving force for good phase separation. Solar cells with improved phase separation of ZnPc:C60 blends (Tsub=140°C, 1:1) reveal a better charge carrier extraction and thus enhanced effciencies of 3.0% in comparison to 2.5% for the reference device (Tsub=30°C, 1:1). In the second part, the impact of molecular orientation within the absorber thin films on light harvesting is examined for pristine ZnPc and diindenoperylene (DIP) films. For film deposition on weakly interacting substrates like glass, SiO2, amorphous organic transport films, or C60, the orientation of DIP and ZnPc molecules is found to be upright standing. In contrast, GIXRD and VASE measurements show that films deposited onto strongly interacting substrates like Au and Ag, as well as on thin PTCDA templating layers lead to nearly flat-lying ZnPc and DIP molecules. Since the molecular transition dipole moment is oriented in the plane of the DIP and ZnPc molecules, the light absorption in films with flat-lying molecules is strongly improved. Unfortunately, an implementation of Au or Ag sublayers in organic solar cells does not result in reliable dependencies since the enhanced absorption by an improved molecular orientation is superimposed by different effects like microcavity and plasmonic effects. The implementation of PTCDA interlayers leads to transport barriers making the solar cell data interpretation difficult. In the last part, the influence of molecular structure on thin film growth is studied for DIP and its derivatives Ph4-DIP and P4-Ph4-DIP, isoviolanthrone, and Bis-nFl-NTCDI derivatives. GIXRD measurements reveal that steric hindrance is induced by the addition of side chains (for Bis-nFl-NTCDI) and phenyl rings (for Ph4-DIP and P4-Ph4-DIP) (N,N-Bis(fluorene-2-yl)-naphthalenetetra-carboxylic diimide) leading to an amorphous thin film growth. In contrast, DIP films and Bis-HFl-NTCDI films are found to be crystalline. The mean molecular orientation and hence the absorption is strongly affected by the different growth modes of DIP and its derivatives. In OSC, the presence of the phenyl rings prevents an effcient phase separation for (P4-)Ph4-DIP:C60 blends which causes diminished charge extraction in comparison to the crystalline DIP:C60 blends. For the Bis-nFl-NTCDI series, the transport properties are significantly worse in the amorphous films composed of Bis-nFl-NTCDI derivatives with alkyl chains in comparison to the nanocrystalline films made of the bare Bis-HFl-NTCDI
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Villanueva, Martha A. "Structures of small organic cluster ions computed using self-consistent field semiempirical molecular orbital methods." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/30323.
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Grimann, Michael [Verfasser]. "Towards Small-Molecule Organic Photovoltaics : Bicontinuous Morphologies in Ternary Blends of Molecular Glasses / Michael Grimann." Kassel : Universitätsbibliothek Kassel, 2018. http://d-nb.info/1167720784/34.
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Dcunha, Ruhee Lancelot. "Towards an Improved Method for the Prediction of Linear Response Properties of Small Organic Molecules." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/104677.
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Quantum chemical methods to predict experimental chiroptical properties by solving the time-dependent Schrödinger equation are useful in the assignment of absolute configurations. Chiroptical properties, being very sensitive to the electronic structure of the system, require highly-accurate methods on the one hand and on the other, need to be able to be computed with limited computational resources.
The calculation of the optical rotation in the solution phase is complicated by solvent effects. In order to capture those solvent effects, we present a study that uses conformational averaging and time-dependent density functional theory calculations that incorporate solvent molecules explicitly in the quantum mechanical region. While considering several controllable parameters along which the system's optical rotation varies, we find that the sampling of the dynamical trajectory and the density functional chosen have the largest impact on the value of the rotation.
In order to eliminate the arbitrariness of the choice of density functional, we would prefer to use coupled cluster theory, a robust and systematically improvable method. However, the high-order polynomial scaling of coupled cluster theory makes it intractable for numerous large calculations, including the conformational averaging required for optical rotation calculations in solution. We therefore attempt to reduce the scaling of a linear response coupled cluster singles and doubles (LR-CCSD) calculation via a perturbed pair natural orbital (PNO++) local correlation approach which uses an orbital space created using a perturbed density matrix. We find that by creating a "combined PNO++" space, incorporating a set of orbitals from the unperturbed pair natural orbital (PNO) space into the PNO++ space, we can obtain well-behaved convergence behavior for both CCSD correlation energies and linear response properties, including dynamic polarizabilities and optical rotations, for the small systems considered.
The PNO++ and combined PNO++ methods require aggressive truncation to keep the computational cost low, due to an expensive two-electron integral transformation at the beginning of the calculation. We apply the methods to larger systems than previously studied and refine them for more aggressive truncation by exploring an alternative form of the perturbed density and a perturbation-including weak pair approximation.Doctor of Philosophy
Theoretical chemistry attempts to provide connections between the structure of molecules and their observable properties. One such family of observables are chiroptical properties, or the effect of the medium on the light which passes through it. These properties include the scattering, absorption and change in polarization of light. Light being classically an electromagnetic field, chiroptical properties can be derived by treating molecules quantum mechanically and the light classically. The prediction of chiroptical properties on computers using the principles of quantum mechanics is still a growing field, being very sensitive to the method used, and requiring considerations of factors such as conformations and anharmonic corrections. Matching experimental properties is an important step in the creation of a reliable method of predicting properties of systems in order to provide more information than can be obtained through experimental observation. This work begins by addressing the problem of matching experimentally obtained quantities. Our results show that current time-intensive methods still fall short in the matching of experimental data. Thus, we then move on to approximating a more robust but computationally expensive method in order to be able to use a more accurate method on a larger scale than is currently possible. On obtaining positive results for small test systems, we test the new method on larger systems, and explore possible improvements to its accuracy and efficiency.
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Asmadi, Aldi. "Crystal structure prediction : a molecular modellling study of the solid state behaviour of small organic compounds." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4441.
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The knowledge of the packing behaviour of small organic compounds in crystal lattices is of great importance for industries dealing with solid state materials. The properties of materials depend on how the molecules arrange themselves in a crystalline environment. Crystal structure prediction provides a theoretical approach through the application of computational strategies to seek possible crystal packing arrangements (or polymorphs) a compound may adopt. Based on the chemical diagrams, this thesis investigates polymorphism of several small organic compounds. Plausible crystal packings of those compounds are generated, and their lattice energies are minimised using molecular mechanics and/or quantum mechanics methods. Most of the work presented here is conducted using two software packages commercially available in this field, Polymorph Predictor of Materials Studio 4.0 and GRACE 1.0. In general, the computational techniques implemented in GRACE are very good at reproducing the geometries of the crystal structures corresponding to the experimental observations of the compounds, in addition to describing their solid state energetics correctly. Complementing the CSP results obtained using GRACE with isostructurality offers a route by which new potential polymorphs of the targeted compounds might be crystallised using the existing experimental data. Based on all calculations in this thesis, four new potential polymorphs for four different compounds, which have not yet been determined experimentally, are predicted to exist and may be obtained under the right crystallisation conditions. One polymorph is expected to crystallise under pressure. The remaining three polymorphs might be obtained by using a seeding technique or the utilisation of suitable tailor made additives.
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Liu, Xinli. "Molecular design of new small molecules and polymers: synthesis, characterization and application in organic solar cells." HKBU Institutional Repository, 2013. https://repository.hkbu.edu.hk/etd_oa/16.
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The molecular design, synthesis, spectroscopic and photophysical characterization of a new series of organic small molecules and transition metal-containing polymers incorporating different n-conjugated chromophores are discussed. The applications of some of these compounds in bulk heterojunction (BHJ) organic solar cells are also outlined. Chapter 1 contains a brief overview on the background of organic solar cells, their structures and performance in solution-processed organic BHJ devices. Chapter 2 presents the synthetic methodology and characterization of a series of new dipyrrin-based materials and their application in organic solar cells. In this section, four metal-based metallopolymers for organic solar cells have been designed, synthesized and two of them have been fabricated for BHJ organic solar cells. Through the alternation of different metal ions and boron element in the same dipyrrin framework, a series of dipyrrin-based metal complexes and BODIPY-containing compounds have been synthesized. Electrochemical analysis and DFT calculations proved that M4 with BODIPY-based structure is more efficient in optimizing the HOMO-LUMO energy level which further increases the Voc value. A full account of the preparation, characterization, photophysical and thermal properties of a new series of benzo[1,2-b:4,5-b']dithiophene (BDT), cyclopenta[2,1-6:3,4-6']dithiophene (CPT) and triphenylamine (TPA) centered small molecules are presented in chapters 3, 4 and 5, respectively. Different acceptor-donor-acceptor (A-D-A) based materials were prepared and employed in organic solar cells in order enhance the power conversion efficiency (PCE) of the devices. Some of the materials have been found to show higher PCEs of up to 3.91%. Given the excellent solution-processability as well as performance advantage, this work provides us a feasible strategy to develop low-cost and high PCE materials in solar cell applications, which would help small molecular organic solar cells to reach a level of practical applications. In chapter 6, four low-bandgap Pt-containing polymers were synthesized and characterized by a variety of techniques. Among them, the largest λonset of 699 nm in solution and λonset of 736 nm in the thin film of P6 were observed and the corresponding energy gap Eg was estimated to be 1.77 eV and 1.68 eV, respectively. After evaluating these oxidation and reduction potentials, P6 also showed the smallest band gap of 1.65 eV with the corresponding HOMO and LUMO energy levels of -5.17 eV and -3.52 eV, respectively. Also, the molecular weights of these polymers were examined by the GPC method. The highest Mn of 24.0 kDa and Mw of 50.4 kDa with the PDI of 2.10 were observed in P8. Chapter 7 and 8 present the concluding remarks and the experimental details of the work described in Chapters 2-6.
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Steen, Robert. "Molecular Electronic Devices based on Ru(II) Thiophenyl Pyridine and Thienopyridine Architecture." Doctoral thesis, Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-10084.
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According to the famous axiom known as Moore’s Law the number of transistors that can be etched on a given piece of ultra-pure silicon, and therefore the computing power, will double every 18 to 24 months. However, around 2020 hardware manufacturers will have reached the physical limits of silicon. A proposed solution to this dilemma is molecular electronics. Within this field researchers are attempting to develop individual organic molecules and metal complexes that can act as molecular equivalents of electronic components such as wires, diodes, transistors and capacitors. In this work we have synthesized a number of new bi- and terdentate thiophenyl pyridine and pyridyl thienopyridine ligands and compared the electrochemical, structural and photophysical properties of their corresponding Ru(II) complexes with Ru(II) complexes of a variety of ligands based on 6-thiophen-2-yl-2,2'-bipyridine and 4-thiophen-2-yl-2,2'-bipyridine motifs. While the electrochemistry of the Ru(II) complexes were similar to that of unsubstituted [Ru(bpy)3]2+ and [Ru(tpy)2]2+, substantial differences in luminescence lifetimes were found. Our findings show that, due to steric interactions with the auxiliary bipyridyl ligands, luminescence is quenched in Ru(II) complexes that incorporate the 6-thiophen-2-yl-2,2'-bipyridine motif, while it was comparable with the luminescence of [Ru(bpy)3]2+ in the Ru(II) complexes of bidentate pyridyl thienopyridine ligands. The luminescence of the Ru(II) complexes based on the 4-thiophen-2-yl-2,2'-bipyridine motif was enhanced compared to [Ru(bpy)3]2+ which indicates that complexes of this category may be applicable for energy/electron-transfer systems. At the core of molecular electronics is the search for molecular ON/OFF switches. Based on the ability of the ligand 6-thiophen-2-yl-2,2'-bipyridine to switch reversibly between cyclometallated and non-cyclometallated modes when complexed with Ru(tpy) we have synthesized a number of complexes, among them a bis-cyclometallated switch based on the ligand 3,8-bis-(6-thiophen-2-yl-pyridin-2-yl)-[4,7]phenanthroline, and examined their electrochemical properties. Only very weak electronic coupling could be detected, suggesting only little, if any, interaction between the ruthenium cores.
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Geng, Ting. "Excited-state dynamics of small organic molecules studied by time-resolved photoelectron spectroscopy." Doctoral thesis, Stockholms universitet, Fysikum, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-140482.
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Ultra-violet and visible light induced processes in small organic molecules play very important roles in many fields, e.g., environmental sciences, biology, material development, chemistry, astrophysics and many others. Thus it is of great importance to better understand the mechanisms behind these processes. To achieve this, a bottom-up approach is most effective, where the photo-induced dynamics occurring in the simplest organic molecule (ethylene) are used as a starting point. Simple substituents and functional groups are added in a controlled manner to ethylene, and changes in the dynamics are investigated as a function of these modifications. In this manner, the dynamics occurring in more complex systems can be explored from a known base. In this thesis, the excited state dynamics of small organic molecules are studied by a combination of time-resolved photoelectron spectroscopy and various computational methods in order to determine the basic rules necessary to help understand and predict the dynamics of photo-induced processes. The dynamics occurring in ethylene involve a double bond torsion on the ππ* excited state, followed by the decay to the ground state coupled with pyramidalization and hydrogen migration. Several different routes of chemical modification are used as the basis to probe these dynamics as the molecular complexity is increased. (i) When ethylene is modified by the addition of an alkoxyl group (-OCnH2n+1), a new bond cleavage reaction is observed on the πσ* state. When modified by a cyano (-CN) group, a significant change in the carbon atom involved in pyramidalization is observed. (ii) When ethylene used to build up small cyclic polyenes, it is observed that the motifs of the ethylene dynamics persist, expressed as ring puckering and ring opening. (iii) In small heteroaromatic systems, i.e., an aromatic ring containing an ethylene-like sub-structure and one or two non-carbon atoms, the type of heteroatom (N: pyrrole, pyrazole O: furan) gives rise to different bond cleavage and ring puckering channels. Furthermore, adding an aldehyde group (-C=O) onto furan, as a way to lengthen the delocalised ring electron system, opens up additional reaction channels via a nπ* state. The results presented here are used to build up a more complete picture of the dynamics that occur in small molecular systems after they are excited by a visible or UV photon, and are used as a basis to motivate further investigations.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 5: Manuscript. Paper 6: Manuscript.
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Wang, Guanyu. "Interfacial Energy Transfer in Small Hydrocarbon Collisions with Organic Surfaces and the Decomposition of Chemical Warfare Agent Simulants within Metal-Organic Frameworks." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100746.
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A molecular-level understanding of gas-surface energy exchange and reaction mechanisms will aid in the prediction of the environmental fate of pollutants and enable advances toward catalysts for the decomposition of toxic compounds. To this end, molecular beam scattering experiments performed in an ultra-high vacuum environment have provided key insights into the initial collision and outcome of critical interfacial processes on model systems.
Results from these surface science experiments show that, upon gas-surface collisions, energy transfer depends, in subtle ways, on both the properties of the gas molecules and surfaces. Specifically, model organic surfaces, comprised of long-chain methyl- and hydroxyl-terminated self-assembled monolayers (SAMs) have been employed to test how an interfacial hydrogen bonding network may affect the ability of a gas-phase compound to thermally accommodate (typically, the first step in a reaction) with the surfaces. Results indeed show that small organic compounds transfer less energy to the interconnected hydroxyl-terminated SAM (OH-SAM) than to the organic surface with methyl groups at the interface. However, the dynamics also appear to depend on the polarizability of the impinging gas-phase molecule. The π electrons in the double bond of ethene (C2H4) and the triple bond in ethyne (C2H2) appear to act as hydrogen bond acceptors when the molecules collide with the OH-SAM. The molecular beam scattering studies have demonstrated that these weak attractive forces facilitate energy transfer. A positive correlation between energy transfer and solubilities for analogous solute-solvent combinations was observed for the CH3-SAM (TD fractions: C2H6 > C2H4 > C2H2), but not for the OH-SAM (TD fractions: C2H6 > C2H2 > C2H4). The extent of energy transfer between ethane, ethene, and ethyne and the CH3-SAM appears to be determined by the degrees of freedom or rigidity of the impinging compound, while gas-surface attractive forces play a more decisive role in controlling the scattering dynamics at the OH-SAM.
Beyond fundamental studies of energy transfer, this thesis provides detailed surface-science-based studies of the mechanisms involved in the uptake and decomposition of chemical warfare agent (CWA) simulants on or within metal-organic frameworks (MOFs). The work presented here represents the first such study reported in with traditional surface-science based methods have been applied to the study of MOF chemistry. The mechanism and kinetics of interactions between dimethyl methylphosphonate (DMMP) or dimethyl chlorophosphate (DMCP), key CWA simulants, and Zr6-based metal-organic frameworks (MOFs) have been investigated with in situ infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD), and DFT calculations. DMMP and DMCP were found to adsorb molecularly (physisorption) to the MOFs through the formation of hydrogen bonds between the phosphoryl oxygen and the free hydroxyl groups associated with Zr6 nodes or dangling -COH groups on the surface of crystallites. Unlike UiO-66, the infrared spectra for UiO-67 and MOF-808, recorded during DMMP exposure, suggest that uptake occurs through both physisorption and chemisorption. The XPS spectra of MOF-808 zirconium 3d electrons reveal a charge redistribution following exposure to DMMP. Besides, the analysis of the phosphorus 2p electrons following exposure and thermal annealing to 600 K indicates that two types of stable phosphorus-containing species exist within the MOF. DFT calculations (performed by Professor Troya at Virginia Tech), were used to guide the IR band assignments and to help interpret the XPS features, suggest that uptake is driven by nucleophilic addition of a surface OH group to DMMP with subsequent elimination of a methoxy substituent to form strongly bound methyl methylphosphonic acid (MMPA). With similar IR features of MOF-808 upon DMCP exposure, the reaction pathway of DMCP in Zr6-MOFs may be similar to that for DMMP, but with the final product being methyl chlorophosphonic acid (elimination of the chlorine) or MMPA (elimination of a methoxy group). The rates of product formation upon DMMP exposure of the MOFs suggest that there are two distinct uptake processes. The rate constants for these processes were found to differ by approximately an order of magnitude. However, the rates of molecular uptake were found to be nearly identical to the rates of reaction, which strongly suggests that the reaction rates are diffusion limited. Overall, and perhaps most importantly, this research has demonstrated that the final products inhibit further reactions within the MOFs. The strongly bound products could not be thermally driven from the MOFs prior to the decomposition of the MOFs themselves. Therefore, new materials are needed before the ultimate goal of creating a catalyst for the air-based destruction of traditional chemical nerve agents is realized.Doctor of Philosophy
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Martinez, Ariza Guillermo, and Ariza Guillermo Martinez. "Exploiting Molecular Diversity to Access Biologically Relevant Chemotypes." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621718.
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Small-molecule libraries with enhanced structural diversity are of value in drug discovery campaigns where novel biologically active hits are desired. As such, multicomponent reactions (MCRs) have proven fruitful to enhance the molecular diversity of chemical collections and expedite forward progression of the drug discovery chain. Bicalutamide (Casodex), an anticancer drug, and Telaprevir (Incivek), an antiviral, are two examples of marketed drugs that can be synthesized using an MCR. The research topic of this dissertation involves the design, discovery, and development of novel MCRs and new combinations of MCRs with post-condensation modifications to generate over twenty-five new drug-like scaffolds in an operationally friendly, atom-economical, time- and cost-effective fashion. The developed chemical methodologies possess inherent 'iterative efficiency','high exploratory power', and 'bond forming efficiency' that allow them to quickly explore chemical space and navigate the 'hypothesis-synthesis-screening' loop that is key for a medicinal chemistry project. The prepared molecules were submitted to the Community for Open Antimicrobial Drug Discovery (CO-ADD) for antimicrobial screening against pathogens that are known to cause drug-resistance infections.
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Mitlin, Sergey. "Studies of Interaction of Small Molecules with Water Condensed Media." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/1273.
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STUDIES OF INTERACTION OF SMALL MOLECULES WITH WATER CONDENSED MEDIAThe present work reports experimental and theoretical studies of the intermolecular interactions in condensed water media. The chemical objects comprise pristine ice and polar organic substances: acetone, acetaldehyde, methanol and chloroform and bi-component water-organic deposits. The experimental part of the studies includes the Fourier Transform Infrared Reflection Absorption spectral (FTIR RAS) examination of the processes of film growth by vapor deposition on cold metal substrate and subsequent annealing. The theoretical studies include ab initio (MP2) and semi-empirical (B3LYP) calculations on the small water and water-organic clusters and classical molecular dynamics simulations of the adsorption of inert guests (Xe/Rn) on the ice surface. The FTIR RA spectral studies reveal that depending on the deposition conditions condensed water media exist in two principal structural forms: noncrystalline and polycrystalline. The former is characterized by porous structure while the latter exists as a non-porous medium with smooth external interface. On annealing, characteristic spectral changes indicate on a rapid crystallization occurring at a certain temperature range. The initial adsorption of organic molecules is accompanied by the hydrogen-bonded coordination between the functional group of organic species and non-coordinated hydroxyl group of the ice surface, the topology of which depends on the electronic properties of the functional group. The computational studies of small water-organic clusters reveal, in particular, two major coordination minima for carbonyl group: a single hydrogen-bonded in-plane complex and a double hydrogen-bonded in-plane complex. The classical molecular dynamics of Xe/Rn species on the ice interface is consistent with two distinctly different surface adsorption sites: one that delocalized over the entire surface and one that confined to small opening in the top ice layer, disrupted by the thermal molecular motion. The penetration barrier is associated with van der Walls repulsion of guest species from the ordered water hexagonal arrangement. A thermo-disruption of latter leads to a rapid diffusion of guest species inside ice medium.
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Min, Jie [Verfasser], and Christoph [Akademischer Betreuer] Brabec. "Solution-Processed Small Molecule Bulk Heterojunction Organic Solar Cells: Molecular, Morphological, Interfacial and Device Engineering / Jie Min. Gutachter: Christoph Brabec." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2015. http://d-nb.info/1078406588/34.
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Parameswaran, Anupama. "Magnetic properties of Mn, Ni and Fe based metal-organic complexes." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-65594.
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This dissertation presents the investigation of magnetic exchange and anisotropy in novel metal-organic complexes containing minimum number of magnetic ions. Such complexes can serve as a model system to understand the exciting magnetic phenomena in such class of materials and also can put forward as candidates for the so called molecular nanomagnets.
A direct assessment of the effective magnetic moment and the effective interaction between the metal ions in the complex can be done using magnetization measurements. Here the magnetization studies are performed as a function of temperature and field using a SQUID magnetometer. Yet another powerful tool to characterize and determine the spin levels, the ESR spectroscopic methods, has also been exploited. The study of the dynamical properties of this class of materials was relevant to understand the relaxation mechanism in the low temperatures. For this a new ac susceptometer has been built in house which was another main objective of this dissertation work. The design, fabrication, calibration and automation done on this device is presented in this thesis. The device has been tested using the known molecular magnet Mn12 acetate, and the antiferromagnet Dy2PdSi3.
The present work is mainly focused on the magnetic properties of Mn, Ni and Fe based organometallic complexes. The studied Mn dimer with different acceptor and donor ligands exhibit the fine tuning of the electron density at the core of molecular complex by variation in ligands. This in turn shows that the change in peripheral ligands can control the magnetism of the molecule. The influence of the change in Ni-S-Ni bond angle in the magnetic exchange interaction is studied in a Ni(2) dimer and a Ni(2) trimer complex. The Ni dimer complex shows a ferromagnetic interaction (J = -42K) whereas trimer shows an antiferromagnetic interaction (J = 140K). Another Ni based complex bridged via phosphorous has been studied which shows the existence of glassy nature at low temperature. Also a polymeric chain compound based on Fe is studied and presented. All these phosphorous or sulphur bridged complexes are novel materials and these are the first data on these complexes.
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Zhou, Zhaoqun. "Combinatorial fabrication & studies of small molecular organic light emitting devices (OLEDs) and structurally integrated OLED-based chemical and biological sensors." [Ames, Iowa : Iowa State University], 2007.
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Kuppusami, Sharmilah. "Metabolite profiling of biological specimens using small molecular weight volatile organic compounds by proton transfer reaction time-of-flight mass spectrometry." Thesis, University of Leicester, 2017. http://hdl.handle.net/2381/39892.
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Metabolite profiling is an analytical study of metabolites that are of low molecular weight which results from normal and pathological cellular processes, using high throughput analytical technologies. This thesis documents the development of the analytical technique of proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) for the analysis of small molecular weight volatile organic compounds (VOCs) in different biological specimens. The work explored the challenges associated with sampling, analysis, and metabolite profiling and identification in microbiology and clinical studies. Initial work focused on the VOCs produced in the headspace of ten Clostridium difficile ribotypes in an attempt to metabolically profile C. difficile at the ribotype level. The C. difficile ribotypes were successfully distinguished from one another. The metabolite profiles suggested that VOC profiling may provide a useful indicator for the identification of the ribotypes. The PTR-ToF-MS system was applied to two clinical trials. The first was a genitourinary clinical trial of patients with sexually transmitted infections (STI), which explored the VOCs emitted from vaginal, cervical and throat swabs to support the hypothesis that metabolite profiling has the potential to identify the presence of infection. The second involved the analysis of exhaled breath to examine the VOCs in the breath of individuals with ovarian cancer (7 female cancer patients, 12 healthy female controls, 5 female with benign cysts) using offline breath collection technique. The premise is that the VOCs in the breath are representative of the VOCs in blood; therefore specific VOCs may be produced in the body caused by tumour cells and these can be detected in breath. Within these applications, the PTR-ToF-MS was able to demonstrate that metabolite profiles are promising biomarkers for disease/infection identification, as well as providing information of cell mechanism and alterations in cells.
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Hofmann, Alexander Johann Ludwig [Verfasser], and Wolfgang [Akademischer Betreuer] Brütting. "The influence of dipolar doping on charge injection and transport in small molecular organic semiconductors / Alexander Johann Ludwig Hofmann ; Betreuer: Wolfgang Brütting." Augsburg : Universität Augsburg, 2020. http://d-nb.info/1219852538/34.
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Bellucci, Luca. "Thermometers at the Nanoscale: a Molecular Approach to Design and Develop Functional Lanthanoid-based Luminescent Materials." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3422334.
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The present work is devoted to the development of lanthanoid-based luminescent thermometers and to the study of the correlations between the thermometric properties and the different building blocks composing the systems. In particular, using rare earth cations, b-diketones (H(b-dike)= dibenzoylmethane, Hdbm; benzoyltrifluoroacetone, Hbta; hexafluoroacetylacetone, Hhfac; thenoyltrifluoroacetone, Htta), and divergent ligands (4,4’-bipyridine, bipy; 4,4’-bipyridine-N-oxide, bipyMO; pyrazine-N-oxide, pyrzMO; 2,5-dihydroxy-1,4-dicarboxylate, H2DHT2-) we prepared molecular systems with different dimensionality: i) dinuclear complexes (0D), ii) Coordination Polymers (CPs, 1D), and Metal-Organic Frameworks (MOFs, 3D).
We started with europium β-dike dinuclear compounds with molecular formula [Eu2(β-dyke)6(L-MO)x] (x=3 for hfac, x=2 for dbm, bta, and tta). Substituting the hfac -CF3 groups with phenyl rings (one in bta, two in dbm) or with a thienyl ring (tta) the β-dike electronic and steric properties were modulated. Conversely, the different steric hindrance of bipyMO and pyrzMO influenced the spatial disposition of the β-dike ligands and the inter- and intra-molecular interactions. In the -50 ÷ 100 °C temperature range, the complexes showed relative thermal sensitivity (Sr) values higher than 1 (generally assumed as a quality criterion for these thermometers) that depended on the nature of both the β-dike and L-MO ligands. The β-diketonates influenced Sr values, thermal operative range, and photostability of the system, while pyrzMO-containing compounds showed improved performances (Sr maximum from 4.6 to 8.1 % °C-1 depending on the β-dike ligand) compared to that based on bipyMO (Sr maximum from 3.4 to 5.1 % °C-1).
In the second part, a series of ratiometric Eu3+/ Tb3+ luminescent thermometers were obtained by mixing different quantities of the two homometallic [Ln(hfac)3(bipy)]n 1D-CPs (Ln3+= Eu3+ and Tb3+) in spectroscopically inert KBr. Here, we studied the effect of the relative metal amounts and of the excitation wavelength on the Sr. For all the samples, Sr values almost independent from the Tb/Eu molar ratio and the excitation wavelength were found between -190 and 110 °C. Each sample showed a peculiar temperature-dependent emission colour, from green to red, that was exploited to develop colour-coded thermometers able to distinguish temperature intervals in the order of 10/ 20 °C.
Then we developed a mild-condition synthetic procedure to obtain single crystal to single crystal post-synthesis modifications of the 3D-MOF [Eu2(H2DHT)3(DMF)4]∙2DMF (DMF= N,N-dimethylformamide) to substitute DMF in the channels with different organic molecules (i.e. CHCl3, imidazole, pyridine, and tetrahydrofuran) and to study the Sr modulation. Depending on the guest molecule, the temperature at which Sr reaches the maximum and its value varied from 2.5 at -90 °C to 4.2 % °C-1 at -10 °C.
Molecular compounds like complexes, CPs and MOFs are ideal systems to study the correlations between structure, composition (in the meaning of molecular functionalization) and functional properties because they can be easily modified through chemical processes. Nevertheless, to exploit the unique properties of these compounds in commonly used tools and instruments they need to be integrated into a device. Surface functionalization is a recurrent way to achieve this target. However, maintaining the control on the arrangement of the various building blocks and characterize the functionalized surface is not straightforward, so that the development of “ad hoc” synthetic protocols and methods is required. In this context, we developed a general procedure for surface functionalization. We exploited the reactivity of lanthanoid N,N-dialkylcarbamate complexes to create an ordered Eu3+-Tb3+ heterobimetallic sequence grafted on amorphous silica using terephthalic acid as divergent ligand to connect the two Ln3+ ions. Photoluminescence was here used to determine the spatial disposition of the two metal ions on silica. In particular, Tb3+-to-Eu3+ energy transfer was used as molecular ruler to study the Ln3+ ions spatial distribution and intermetal distances that allow us to obtain data supporting the formation of the desired sequence.Questo lavoro è volto allo sviluppo di termometri molecolari a base di ioni lantanoidei ed allo studio delle correlazioni tra proprietà termometriche ed i diversi building blocks che compongono i sistemi. In particolare, usando cationi lantanoidei, β-dichetoni (H(β-dike)= dibenzoilmetano, Hdbm; benzoiltrifluoroacetone, Hbta; esafluoroacetilacetone, Hhfac; tenoiltrifluoroacetone, Htta), e leganti divergenti (4,4’-bipiridina, bipy; 4,4’-bipiridina-N-ossido, bipyMO; pirazina-N-ossido, pyrzMO; 2,5-diidrossi-1,4-dicarbossilato, H2DHT2-) sono stati preparati sistemi molecolari con diversa dimensionalità: i) complessi dinucleari (0D), polimeri di coordinazione (CPs, 1D) e Metal Organic Frameworks (MOFs, 3D). Nei complessi dinucleari di europio [Eu2(β-dike)6(L-MO)x] (x=3 per hfac, x=2 per dbm, bta, and tta) le proprietà elettroniche e steriche del β-dichetonato sono state modulate sostituendo i gruppi -CF3 di hfac con anelli fenilici (uno nel bta, due nel dbm) o con un anello tienilico (tta). Il diverso ingombro sterico dei leganti bipyMO e pyrzMO influenzarono invece la disposizione spaziale dei leganti β-dichetonato e le loro interazioni inter- ed intra-molecolari. I complessi mostrarono valori di sensibilità termica relativa (Sr) maggiori di 1 (valore generalmente usato come criterio di qualità per questi termometri) dipendenti dalla natura dei leganti β-dike e L-MO nell’intervallo di temperatura -50 ÷ 100 °C. I leganti β-dichetonato influenzarono i valori di Sr, l’intervallo applicativo di temperature e la fotostabilità dei complessi. I composti contenenti pyrzMO mostrarono performances migliori (Sr massimo da 4.6 a 8.1 % °C-1 a seconda del β-dike) rispetto agli analoghi con bipyMO (Sr massimo da 3.4 a 5.1 % °C-1). Successivamente è stata ottenuta una serie di termometri luminescenti raziometrici a base di Eu3+ e Tb3+ miscelando diverse quantità dei due polimeri di coordinazione 1D [Ln(hfac)3(bipy)]n (Ln3+= Eu3+ e Tb3+) in KBr (inerte dal punto di vista spettroscopico). In questo caso è stato studiato l’effetto su Sr della quantità relativa dei due ioni metallici e della lunghezza d’onda di eccitazione nell’intervallo -190 ÷ 110 °C. Per tutti i campioni i valori di Sr risultarono non influenzati dal rapporto molare Tb/Eu e dalla lunghezza d’onda di eccitazione. Ciascun campione mostrò un peculiare colore emesso (dal verde al rosso) in funzione della temperatura. Ciò è stato sfruttato per sviluppare termometri basati su codici di colori capaci di distinguere intervalli di temperatura di 10/ 20 °C. È stata inoltre sviluppata una procedura basata su condizioni blande per attuare la modifica post-sintetica da cristallo singolo a cristallo singolo del MOF [Eu2(H2DHT)3(DMF)4]∙2DMF (DMF= N,N-dimetilformamide) sostituendo la DMF nei canali con diverse molecole (CHCl3, imidazolo, piridina e tetraidrofurano) per studiare la modulazione di Sr. A seconda della molecola ospitata, la temperatura alla quale si raggiunge il massimo di Sr e il suo valore variarono da 2.5 a -90 °C a 4.2 % °C-1 a -10 °C. Composti molecolari come complessi, CPs e MOFs sono ideali per lo studio delle correlazioni tra struttura, composizione (nel senso di funzionalizzazione molecolare) e proprietà funzionali in quanto facilmente modificabili tramite processi chimici. Tuttavia, è necessario integrare questi sistemi in dispositivi per sfruttare le loro proprietà in strumenti di uso comune. La funzionalizzazione di superfici è una procedura comunemente usata per questo scopo. In questo caso tuttavia, non è semplice mantenere il controllo sulla disposizione dei vari building blocks e caratterizzare la superficie funzionalizzata così che è fondamentale sviluppare un adeguato protocollo sintetico. In questo contesto, è stata messa a punto una procedura sintetica per la funzionalizzazione di superfici. Per questo scopo è stata sfruttata la reattività degli N,N-dialchilcarbammati lantanoidei per creare una sequenza eterobimetallica Eu3+-Tb3+ ordinata aggraffata su silice amorfa, usando l’acido tereftalico come legante divergente per connettere i due centri metallici. La fotoluminescenza è stata qui utilizzata per determinare la distribuzione spaziale dei due ioni metallici sulla silice. In particolare, fenomeni di trasferimento energetico dal Tb3+ all’Eu3+ sono stati usati come righello molecolare per determinare la distribuzione e le distanze intermetalliche ottenendo dati a supporto della formazione della sequenza desiderata.
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Brückner, Charlotte [Verfasser], and Bernd [Gutachter] Engels. "The Electronic Structure and Optoelectronic Processes at the Interfaces in Organic Solar Cells Composed of Small Organic Molecules - A Computational Analysis of Molecular, Intermolecular, and Aggregate Aspects / Charlotte Brückner ; Gutachter: Bernd Engels." Würzburg : Universität Würzburg, 2016. http://d-nb.info/1148944737/34.
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Schünemann, Christoph Verfasser], Karl [Akademischer Betreuer] [Leo, and Manfred [Akademischer Betreuer] Stamm. "Organic Small Molecules: Correlation between Molecular Structure, Thin Film Growth, and Solar Cell Performance / Christoph Schünemann. Gutachter: Karl Leo ; Manfred Stamm. Betreuer: Karl Leo." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://d-nb.info/1068443944/34.
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Schünemann, Christoph [Verfasser], Karl [Akademischer Betreuer] Leo, and Manfred [Akademischer Betreuer] Stamm. "Organic Small Molecules: Correlation between Molecular Structure, Thin Film Growth, and Solar Cell Performance / Christoph Schünemann. Gutachter: Karl Leo ; Manfred Stamm. Betreuer: Karl Leo." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-105169.
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Repasky, Paul J. "Novel Trisubstituted Arylidene Oxindoles with Potent Anti-Apoptotic Properties." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1310326721.
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Perumal, Ajay Kumar. "Alternating current electroluminescence (AC-EL) with organic light emitting material." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-89750.
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We demonstrate a new approach for fabricating alternating current driven organic electroluminescent devices using the concept of doping in organic semiconductors. Doped charge transport layers are used for generation of charge carriers within the device, hence eliminating the need for injecting charge carriers from external electrodes.
The device is an organic-inorganic hybrid: We exploit the mechanical strength and chemical stability of inorganic semiconductors and combine it with better optical properties of organic materials whose emission color can be chemically tuned so that it covers the entire visible spectrum. The device consists of an organic electroluminescence (EL) layer composed of unipolar/ambipolar charge transport materials doped with organic dyes (10 wt% ) as well as molecularly doped charge generation layers enclosed between a pair of transparent insulating metal oxide layers. A transparent indium doped tin oxide (ITO) layer acts as bottom electrode for light outcoupling and Aluminium (Al) as top reflective electrode. The electrodes are for applying field across the device and to charge the device, instead of injection of charge carriers in case of direct current (DC) devices. Bright luminance of up to 5000 cd m-2 is observed when the device is driven with an alternating current (AC) bias. The luminance observed is attributed to charge carrier generation and recombination, leading to formation of excitons within the device, without injection of charge carriers through external electrodes.
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Urig, Christina S. "EVALUATION OF SINGLE MOLECULE DIODES FABRICATED VIA ELECTRON-BEAM LITHOGRAPHY AND METAL-ORGANIC FRAMEWORKS INCORPORATING TWO NOVEL LIGANDS, A TRIGONAL PLANAR CARBOXYLATE LIGAND AND A TETRAHEDRAL TETRAZOLATE-BASED LIGAND." Miami University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=miami1176829199.
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SORANA, FEDERICO. "Role of organic chemistry in the study and preparation of small molecules: new synthetic methodologies, mechanistic aspects and synthesis of new molecular entities for sar studies." Doctoral thesis, Università degli Studi di Camerino, 2014. http://hdl.handle.net/11581/401838.
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Navaroli, Deanna M. "Molecular Mechanisms of Endocytosis: Trafficking and Functional Requirements for the Transferrin Receptor, Small Interfering RNAs and Dopamine Transporter: A Dissertation." eScholarship@UMMS, 2012. https://escholarship.umassmed.edu/gsbs_diss/592.
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Endocytosis is an essential function of eukaryotic cells, providing crucial nutrients and playing key roles in interactions of the plasma membrane with the environment. The classical view of the endocytic pathway, where vesicles from the plasma membrane fuse with a homogenous population of early endosomes from which cargo is sorted, has recently been challenged by the finding of multiple subpopulations of endosomes. These subpopulations vary in their content of phosphatidylinositol 3- phosphate (PI3P) and Rab binding proteins. The role of these endosomal subpopulations is unclear, as is the role of multiple PI3P effectors, which are ubiquitously expressed and highly conserved. One possibility is that the different subpopulations represent stages in the maturation of the endocytic pathway. Alternatively, endosome subpopulations may be specialized for different functions, such as preferential trafficking of specific endocytosed cargo. To determine whether specific receptors are targeted to distinct populations of endosomes, we have built a platform for total internal reflection fluorescence (TIRF) microscopy coupled with structured illumination capabilities named TESM (TIRF Epifluorescence Structured light Microscope.) In this study, TESM, along with standard biochemical and molecular biological tools, was used to analyze the dynamic distribution of two highly conserved Rab5 and PI3P effectors, EEA1 and Rabenosyn-5, and systematically study the trafficking of transferrin. Rabenosyn-5 is necessary for proper expression of the transferrin receptor as well as internalization and recycling of transferrin-transferrin receptor complexes. Results of combining TIRF with structured light Epifluorescence (SLE) indicate that the endogenous populations of EEA1 and Rabenoysn-5 are both distinct and partially overlapping.
The application of antisense oligonucleotides as potential therapeutic agents requires effective methods for their delivery to the cytoplasm of target cells. In collaboration with RXi Pharmaceuticals we show the efficient cellular uptake of the antisense oligonucleotide sd-rxRNA® in the absence of delivery vehicle or protein carrier. In this study TIRF, SLE, and biochemical approaches were utilized to determine whether sd-rxRNA traffics and functions along specific endosomal pathways. Sd-rxRNA was found to traffic along the degradative pathway and require EEA1 to functionally silence its target. These new findings will help define the cellular pathways involved in RNA silencing.
Neurotransmitter reuptake and reuse by neurotransmitter transport proteins is fundamental to transmitter homeostasis and synaptic signaling. In order to understand how trafficking regulates transporters in the brain and how this system may be disregulated in monoamine-related pathologies, the transporter internalization signals and their molecular partners must be defined. We utilized a yeast two-hybrid system to identify proteins that interact with the dopamine transporter (DAT) endocytic signal. The small, membrane associated, GTPase Rin was determined to specifically and functionally interact with the DAT endocytic signal, regulating constitutive and protein kinase C (PKC) – stimulated DAT endocytosis. The results presented in this study provide new insights into functions and components of endocytosis and enhance the understanding of endocytic organization.
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Cao, Yichen. "APPLICATION OF LINEAR FREE ENERGY RELATIONSHIPS IN THE PREDICTION OF TRIGLYCERIDE/WATER PARTITION COEFFICIENTS AND LIPID BILAYER PERMEABILITY COEFFICIENTS OF SMALL ORGANIC MOLECULES AND PEPTIDES." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/655.
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Computational methods such as linear free energy relationships (LFERs) offer a useful high-throughput solution to quickly evaluate drug developability, e.g. membrane permeability, organic solvent/water partition coefficients, and solubility. LFERs typically assume the contribution of structural components/functional groups to the overall properties of a given molecule to be constant and independent. This dissertation describes a series of studies in which linear free energy relationships were developed to predict solvation of small organic molecules in lipid formulations, specifically, triglyceride containing solvents and phospholipid-based liposomes. The formation of intermolecular HBs in triglyceride solvents (homogenous with H-bond accepting ability) and intramolecular HBs within the bilayer barrier domain (hydrocarbon-like) proved to be the major factors to consider in developing LFERs to account for the increased oil/water partition coefficients and enhanced bilayer permeability of small organic molecules.
The triglyceride solvent/water partition coefficients of a series of model compounds varying in polarity and H-bond donating/accepting capability were used to establish a correlation between the solvent descriptors and the ester concentration in these solvents using the Abraham LFER approach. The LFER analyses showed that the descriptors representing the polarizability and H-bond basicity of the solvents vary systematically with the ester concentration.
A fragment-based LFER to predict membrane permeability or 1,9- decadiene/water partition coefficients of small organic molecules including small peptides was systematically constructed using a total of 47 compounds. Significant nonadditivity was observed in peptides in that the contribution of the peptide backbone amide to the apparent transfer free energy from water into the bilayer barrier domain is considerably smaller than that of a “well-isolated” amide and greatly affected by adjacent polar substituents on the C-termini.
In order to explain the phenomenon of nonadditivity, the formation of intramolecular HBs and inductive effects of neighboring polar groups on backbone amide, were investigated using FTIR and MD simulations. Both spectroscopic and computational results provided supportive evidence for the hypothesis that the formation of intramolecular HBs in peptides is the main reason for the observed nonadditivity of Δ(ΔG°)-CONH-. The MD simulation results showed that the inductive effect of neighboring groups is not as important as the effect of intramolecular HBs.
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Malaby, Heidi L. H. "Identification of Molecular Determinants that Shift Co- and Post-Translational N-Glycosylation Kinetics in Type I Transmembrane Peptides: A Dissertation." eScholarship@UMMS, 2014. https://escholarship.umassmed.edu/gsbs_diss/702.
Full textAbstract:
Asparagine (N)-linked glycosylation occurs on 90% of membrane and secretory proteins and drives folding and trafficking along the secretory pathway. The N-glycan can be attached to an N-X-T/S-Y (X,Y ≠ P) consensus site by one of two oligosaccharyltransferase (OST) STT3 enzymatic isoforms either during protein translation (co-translational) or after protein translation has completed (post-translational). While co-translational N-glycosylation is both rapid and efficient, post-translational N-glycosylation occurs on a much slower time scale and, due to competition with protein degradation and forward trafficking, could be detrimental to the success of a peptide heavily reliant on post-translational N-glycosylation. In evidence, mutations in K+ channel subunits that shift N-glycosylation kinetics have been directly linked to cardiac arrhythmias. My thesis work focuses on identifying primary sequence factors that affect the rate of N-glycosylation.
To identify the molecular determinants that dictate whether a consensus site acquires its initial N-glycan during or after protein synthesis, I used short (~ 100-170 aa) type I transmembrane peptides from the KCNE family (E1-E5) of K+ channel regulatory subunits. The lifetime of these small membrane proteins in the ER translocon is short, which places a significant time constraint on the co-translational N-glycosylation machinery and increases the resolution between co- and post-translational events. Using rapid metabolic pulse-chase experiments described in Chapter II, I identified several molecular determinants among native consensus sites in the KCNE family that favor co-translational N-glycosylation: threonine containing-consensus sites (NXT), multiple N-terminal consensus sites, and long C-termini. The kinetics could also be shifted towards post-translational N-glycosylation by converting to a serine containing-consensus site (NXS), reducing the number of consensus sites in the peptide, and shortening the C-termini.
In Chapter III, I utilized an E2 scaffold peptide to examine the N-glycosylation kinetics of the middle X residue in an NXS consensus site. I found that large hydrophobic and negatively charged residues hinder co-translational N-glycosylation, while polar, small hydrophobic, and positively charged residues had the highest N-glycosylation efficiencies. Poorly N-glycosylated NXS consensus sites with large hydrophobic and negatively charged X residues had a significantly improved co-translational N-glycosylation efficiency upon conversion to NXT sites.
Also in Chapter III, I adapted a siRNA knockdown strategy to definitively identify the OST STT3 isoforms that perform co- and post-translational N-glycosylation for type I transmembrane substrates. I found that the STT3A isoform predominantly performs co-translational N-glycosylation while the STT3B isoform predominantly performs post-translational N-glycosylation, in agreement with the roles of these enzymatic subunits on topologically different substrates.
Taken together, these findings further the ability to predict the success of a consensus site by primary sequence alone and will be helpful for the identification and characterization of N-glycosylation deficiency diseases.
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Malaby, Heidi L. H. "Identification of Molecular Determinants that Shift Co- and Post-Translational N-Glycosylation Kinetics in Type I Transmembrane Peptides: A Dissertation." eScholarship@UMMS, 2004. http://escholarship.umassmed.edu/gsbs_diss/702.
Full textAbstract:
Asparagine (N)-linked glycosylation occurs on 90% of membrane and secretory proteins and drives folding and trafficking along the secretory pathway. The N-glycan can be attached to an N-X-T/S-Y (X,Y ≠ P) consensus site by one of two oligosaccharyltransferase (OST) STT3 enzymatic isoforms either during protein translation (co-translational) or after protein translation has completed (post-translational). While co-translational N-glycosylation is both rapid and efficient, post-translational N-glycosylation occurs on a much slower time scale and, due to competition with protein degradation and forward trafficking, could be detrimental to the success of a peptide heavily reliant on post-translational N-glycosylation. In evidence, mutations in K+ channel subunits that shift N-glycosylation kinetics have been directly linked to cardiac arrhythmias. My thesis work focuses on identifying primary sequence factors that affect the rate of N-glycosylation.
To identify the molecular determinants that dictate whether a consensus site acquires its initial N-glycan during or after protein synthesis, I used short (~ 100-170 aa) type I transmembrane peptides from the KCNE family (E1-E5) of K+ channel regulatory subunits. The lifetime of these small membrane proteins in the ER translocon is short, which places a significant time constraint on the co-translational N-glycosylation machinery and increases the resolution between co- and post-translational events. Using rapid metabolic pulse-chase experiments described in Chapter II, I identified several molecular determinants among native consensus sites in the KCNE family that favor co-translational N-glycosylation: threonine containing-consensus sites (NXT), multiple N-terminal consensus sites, and long C-termini. The kinetics could also be shifted towards post-translational N-glycosylation by converting to a serine containing-consensus site (NXS), reducing the number of consensus sites in the peptide, and shortening the C-termini.
In Chapter III, I utilized an E2 scaffold peptide to examine the N-glycosylation kinetics of the middle X residue in an NXS consensus site. I found that large hydrophobic and negatively charged residues hinder co-translational N-glycosylation, while polar, small hydrophobic, and positively charged residues had the highest N-glycosylation efficiencies. Poorly N-glycosylated NXS consensus sites with large hydrophobic and negatively charged X residues had a significantly improved co-translational N-glycosylation efficiency upon conversion to NXT sites.
Also in Chapter III, I adapted a siRNA knockdown strategy to definitively identify the OST STT3 isoforms that perform co- and post-translational N-glycosylation for type I transmembrane substrates. I found that the STT3A isoform predominantly performs co-translational N-glycosylation while the STT3B isoform predominantly performs post-translational N-glycosylation, in agreement with the roles of these enzymatic subunits on topologically different substrates.
Taken together, these findings further the ability to predict the success of a consensus site by primary sequence alone and will be helpful for the identification and characterization of N-glycosylation deficiency diseases.
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Holzmüller, Felix. "Influence of processing conditions on morphology and performance of vacuum deposited organic solar cells." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-228977.
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This thesis discusses vacuum deposited organic solar cells. It focuses on the investigation of new donor molecules blended with the standard electron acceptor C60. These donor-acceptor heterojunctions form the photoactive system of organic solar cells. In addition, the influence of the processing conditions on the morphology of the blend layers is investigated, as the morphology is crucial for an efficient generation of free charge carriers upon photon absorption.
Bulk heterojunction solar cells with the donor DTDCTB are deposited at different substrate temperatures. We identify three substrate temperature regimes, discriminated by the behavior of the fill factor (FF ) as a function of the blend layer thickness. Devices deposited at RT have a maximum FF between 50 and 70 nm blend thickness, while devices deposited at 110 °C have a monotonically decreasing FF. At Tsub=85 °C, the devices have an S-kinked current-voltage curve. Grazing incidence wide angle X-ray scattering measurements show that this peculiar behavior of the FF is not correlated with a change in the crystallinity of the DTDCTB, which stays amorphous. Absorption measurements show that the average alignment of the molecules inside the blend also remains unchanged. Charge extraction measurements (OTRACE) reveal a mobility for the 110 °C device that is an order of magnitude higher than for the RT device. The difference in mobility can be explained by a higher trap density for the RT samples as measured by impedance spectroscopy. Despite slightly higher carrier lifetimes for the RT device obtained by transient photovoltage measurements, its mobility-lifetime product is still lower than for the 110 °C devices.
Based on DTDCTB, three new donor materials are designed to have a higher thermal stability in order to achieve higher yields upon material purification using gradient sublimation. For PRTF, the thermal stability is increased demonstrated by a higher yield upon sublimation. However, all new materials have a reduced absorption as compared to DTDCTB, which limits the short current density, and the FF is more sensitive to an increase of the blend layer thickness. The highest power conversion efficiency is achieved for a PRTF:C60 solar cell with 3.8%. Interestingly, PRTF:C60 solar cells show exceptionally low nonradiative voltage losses of only 0.26 V.
Another absorber molecule is the push-pull chromophore QM1. Scanning electron microscope (SEM) measurements show a growth of the molecule in nanowires on several substrates. The nanowires have lengths up to several micrometers and are several tens of nanometers wide. The formation of the nanowires is accompanied by a strong blue shift (650 meV) of the thin film absorption spectrum in comparison to the absorption in solution, which is attributed to H-aggregation of the molecules. Furthermore, the thin film absorption onset reaches up to 1100 nm, making the material a suitable candidate for a near infrared absorber in organic solar cells. For a solar cell in combination with C60, a power conversion efficiency of 1.9% was achieved with an external quantum efficiency of over 19% for the spectral range between 600 and 1000 nm.
The method of “co-evaporant induced crystallization” as a means to increase the crystallinity of blend layers without increasing the substrate temperature during the deposition is investigated. Mass spectrometry (LDI-ToF-MS) measurements show that polydimethylsiloxane (PDMS), which is used as a co-evaporant, decomposes during the evaporation and only lighter oligomers evaporate. Quartz crystal microbalance (QCM) measurements prove that the detection of PDMS saturates at higher amounts of evaporated material. LDI-ToF-MS measurements show further that the determination of the volatilization temperature by QCM measurements is highly error prone. The method was applied to zinc phthalocyanine (ZnPc) :C60 solar cells, accepting the insertion of PDMS into the blend layer. Diffraction (GIXRD) measurements show a large increase in crystallinity. ZnPc:C60 solar cells produced by applying the method reveal a similar behavior as solar cells processed at a higher substrate temperature.
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Sugiharto, Eko. "Complexation de l'ion vanadyle, vo**(2+) par des ligands polycoordinantes ouverts ou macrocycliques : analogies avec l'ion vo::(2)**(+)." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13100.
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