Dissertations / Theses on the topic 'Synthetic Oligomers'
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Szczypiński, Filip Tomasz. "Ester-based synthetic information oligomers." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/289396.
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Stross, Alexander. "Synthetic H-bonding information oligomers." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/12365/.
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The nucleic acids contain chemical information in the form of a sequence of bases. This information content is expressed through sequence selective duplex formation and template directed synthesis. To date, the only programmable artificial information molecules that can truly rival the nucleic acids, in terms of their function, are structurally very similar to the nucleic acids. This thesis describes a synthetic approach to duplex forming hydrogen bonding oligomers that contain information in the form of a sequence of H-bond donor and acceptor groups, in the pursuit of a programmable material that is orthogonal to the nucleic acids. Chapter 1 is a literature review of natural and synthetic information molecules and their applications in nanotechnology, including an overview of the structurally reengineered versions of the nucleic acids, foldamers, template polymerisation and synthetic duplexes. The review highlights the absence of totally synthetic information oligomers, that are orthogonal to the nucleic acids, and Chapter 2 sets out the aims of this thesis, which is to address this gap. Chapter 3 describes the synthesis of oligomers equipped with phenol H-bond donors and phosphine oxide H-bond acceptors. Through cooperative H-bond formation, these oligomers form double stranded complexes, which were characterised by NMR titrations and thermal denaturation experiments. For each additional H-bond there is an order of magnitude increase in association constant. In Chapter 4 it is demonstrated that the modular design for the oligomers in Chapter 3 represents a general strategy to synthetic information oligomers. Two new classes of H-bond acceptor oligomer were synthesised, bearing pyridine and pyridine N-oxide groups. Both these systems also exhibit cooperative duplex formation with H-bond donor oligomers, which were characterised by NMR titration. Chapter 5 examines the ability of mixed sequence 3-mers formed of H-bond donors (phenol) and H-bond acceptors (pyridine N-oxide) to form duplexes in a sequence selective manner. All 8 combinations of donor and acceptor were synthesised, and NMR titrations were used to measure the association constants for each pairwise combination of oligomers. Sequence matched duplexes generally have the highest association constants, but there are some anomalies.
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Swain, Jonathan. "Phenylacetylene oligomers as synthetic information molecules." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/279084.
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Nucleic acids store genetic information in the sequence of nucleobases. Through duplex formation and template directed synthesis, the information stored in nucleic acids determines their three-dimensional structure and function. Nucleic acids are essential molecules for biological processes and have been used in nanotechnology. Modified nucleic acids have been synthesised that still form duplexes and can be tolerated by enzymes, suggesting that it is possible to construct a synthetic system comparable to nucleic acids, orthogonal to nucleic acids. This thesis describes the synthesis of a new class of synthetic information molecule, characterisation of the duplex forming properties, and attempts at templated oligomerisation reactions. The new synthetic information molecule is based on the phenylacetylene oligomer framework developed by Moore and co-workers. Recognition was achieved via a base-pair that is made from a single point high affinity H-bond, with phenol as the H-bond donor (D) and phosphine oxide as the H-bond acceptor (A). The Sonogashira coupling was used to construct the phenylacetylene oligomer backbone. The AA, DD and AD 2-mers were synthesised and complementary 2-mers showed cooperative duplex formation. No intramolecular H-bonding due to folding was observed in the AD mixed 2-mer. Longer oligomers were synthesised using a method of oligomerisation and chromatographic separation by reverse-phase preparatory HPLC. Homo-oligomers up to the 7-mer were isolated and binding studies between complementary all donor, all acceptor homo-oligomers showed increasing duplex stability with each additional recognition unit in the oligomer chain. Oligomers containing both acceptor and donor recognition modules in the same chain were synthesised and NMR dilution studies were used to investigate their ability to fold. Preliminary experiments were carried out to evaluate the ability of these information molecules to template oligomerisation reactions, but when reactions were carried out at concentrations low enough for a significant template effect, no coupling reactions were observed.
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Iadevaia, Giulia. "A synthetic approach to H-bonding information oligomers." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/6370/.
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Trinh, Thanh Tam. "Synthèse itérative supportée de macromolécules à séquences contrôlées." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF006/document.
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Des oligonylons et des oligo(triazole-amide)s possédant des séquences contrôlées de comonomères ont été étudiés dans cette thèse. Ces polymères ont été synthétisés par des approches itératives ne nécessitant pas l’emploi de groupes protecteurs. Les oligonylons ont été préparés par une approche de type «AA+BB», c.à.d. par couplage alterné de monomères diacides (AA) et diamines (BB) utilisés en excès. Cette approche s’est avérée possible mais a conduit à des réactions non-souhaitées de pontage intermoléculaire. Une approche plus robuste de type «AB+CD» a été utilisée pour la synthèse des oligo(triazole-amide)s. Dans ce cas, les polymères ont été obtenus par couplage chimioséléctif de monomères bi-fonctionnels de type AB (A = acide carboxylique, B = alcyne) et CD (C = amine, D = azoture). Cette méthode a permis la synthèse d’oligomères monomoléculaires. De plus, un codage moléculaire de type binaire (0, 1) a pu être créé sur ces oligomères. Cependant, cette approche itérative reste lente et limitée à de courtes séquences. Afin de simplifier le processus, une stratégie basée sur des couplages de trimères a été étudiée. Cette nouvelle approche a permis la synthèse de longues séquences codées contenant un octet moléculaireIn this thesis, iterative syntheses of sequence-controlled oligonylons and oligo(triazole-amide)s by protecting group-free approaches have been described. Oligonylons have been prepared by an «AA+BB» approach i.e. by stepwise couplings of a large excess of diacids (AA) and diamines (BB) monomers. This strategy was interesting but could not prevent the formation of bridged molecules. Therefore, an «AB+CD» strategy has been adopted for the synthesis of oligo(triazole-amide)s. In this case, the growth of oligomers was controlled by consecutive chemoselective couplings of AB (A = acid, B = alkyne) and CD (C = amine, D = azide) monomers. This approach was found to be efficient for the preparation of encoded monodisperse oligo(triazole-amide)s whose sequence is based on a binary code (0, 1). However, this iterative approach is slow and is not adapted to longer sequences. Consequently, a strategy based on trimers couplings has been developed in order to simplify the process. This new approach has enabled the synthesis of long code sequences containing a molecular byte
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Lightowler, Stephen. "Palladium-catalysed cross-coupling reactions in the synthesis of novel organic polymers and monodisperse oligomers." Thesis, University of Hull, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342874.
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Henry, Brian Lawrence. "Novel Sulfated 4-Hydroxycinnamic Acid Oligomers as Potent Anticoagulants." VCU Scholars Compass, 2007. http://scholarscompass.vcu.edu/etd/1462.
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The occurrence of thrombosis in several pathophysiological conditions creates a huge need for anticoagulation therapy. Thrombin and factor Xa have been prime targets for regulation of clotting through the direct and indirect mechanism of inhibition. This work investigates chemo-enzymatically prepared oligomers of 4-hydroxycinnamic acids (DHPs) as potential anticoagulants. Oligomers were prepared through peroxidase-catalyzed oxidative coupling of 4-hydroxycinnamic acids. The products resulting from this reaction are called CDs, FDs and SDs. Structurally, these sulfated DHPs are unique and do not resemble any of the anticoagulants known in the literature.DHP oligomers were found to increase clotting times at concentrations comparable to heparin. Studies in blood and plasma show that DHPs possess an anticoagulation profile similar to enoxaparin. To understand the mechanism of action of DHPs, we studied the inhibition of thrombin, FXa, FIXa, and FVIIa in the presence and absence of antithrombin. CDs and FDs display a preference for direct inhibition of thrombin and FXa, and exhibit a high level of specificity over FIXa and FVIIa. In the presence of AT, CDs and FDs displayed weaker inhibition of FXa and thrombin suggesting that binding to AT is a competitive side reaction. SDs exhibited potent inhibition of FXa and thrombin in the absence of antithrombin, but was inactive against FIXa and FVIIa representing the best selectivity among the DHPs. For SDs, inhibition of all the pro-coagulant enzymes favored the antithrombin dependent pathway. Binding studies were performed to determine how CDs directly inhibits thrombin. Competitive binding studies suggest that CDs interacts with exosite II and disrupts the catalytic triad of thrombin. These results indicate that the preferred mechanism of CDs action is exosite II mediated allosteric disruption of thrombin. CDs appears to be the first exosite II mediated DTI and this represents a novel mechanism of inhibitor function. The inhibition characteristics of DHPs are unique and radically different in structure from all the current clinically used anticoagulants. To the best of our knowledge this dual mechanism of anticoagulation and unique binding mode has not been described as yet in literature and represents a novel strategy that our laboratory has discovered.
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Sprafke, Johannes Klaus. "Supramolecular control of synthesis and electronic structure of porphyrin oligomers." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:520bfa69-8cd5-4615-96fb-487651dd557a.
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The work described in this thesis demonstrates the use of supramolecular chemistry in the template-directed synthesis of porphyrin nanorings and as a tool to control conformation and topology of π-conjugated porphyrin oligomers. Particular emphasis is placed on changes to the electronic structure of these oligomers depending on their conformation. Chapter 1 gives an overview of π-conjugated porphyrin oligomers and conjugated macrocycles in general, followed by an introduction into supramolecular cooperativity and small angle X-ray scattering in solution. Chapter 2 describes advances in the synthesis, solution structure elucidation and optoelectronic properties of a fully conjugated cyclic porphyrin hexamer. The high rigidity and symmetry of this nanoring as well as its bent π-system lead to a significant decrease in its HOMO-LUMO gap. The resulting near-infrared emission was exploited in the fabrication of light emitting diodes, demonstrating the use of a bent topology for minimizing aggregation in thin films. The synthesis of a [12]porphyrin nanoring using a hexadentate template is presented in Chapter 3. The concept of Vernier templating is introduced as a general strategy for the synthesis of large monodisperse macrocycles. The nanoring is characterized and its cooperative binding to two template molecules is studied. In Chapter 4 a bidentate ligand is used in the cooperative formation of a sandwich complex beween two nanorings. Chapter 5 provides an analysis of the rigidity of the butadiyne linked porphyrin oligomers used throughout this thesis. A linear chain is significantly more flexible in solution than on a surface where it is confined within two dimensions. Analysis of the persistence length indicates that a porphyrin nanoring with more than around 20 units would not be significantly strained. The supramolecular binding of linear porphyrin oligomers to carbon nanotubes is analyzed in Chapter 6. The binding strength increases sharply with oligomer length and binding is strongest with (8,6) and (7,5) tubes. The energy level alignment in these porphyrin CNT complexes appears to be favorable for an application in photovoltaics. In Chapter 7 bisamidine-carboxylate salt bridges together with zinc-nitrogen coordination chemistry are used to access a variety of topologies in assemblies based on carboxylic acid functionalized porphyrin dimers.
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Sun, Xiaohua. "Synthesis and properties of monodisperse oligomer-substituted calix[4]arene assemblies and related oligomers." HKBU Institutional Repository, 2006. http://repository.hkbu.edu.hk/etd_ra/706.
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Yao, Dandan. "Synthesis of new conjugated meso porphyrin dendrimers and oligomers and study of their optical properties." Thesis, Rennes, INSA, 2015. http://www.theses.fr/2015ISAR0008/document.
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Au cours de cette thèse, nous avons synthétisé et caractérisé de nouveaux composés en utilisant le macrocycle porphyrine en tant que brique moléculaire. L’objectif, après la synthèse, était d’étudier les propriétés photophysiques de ces nouvelles molécules. Plus précisément, nous avons considérés trois groupes de dendrimères fluorènyles-porphyrines et deux oligomères avec des structures conjuguées. Les corrélations structures et propriétés optiques ont été discutées en détail, ainsi que le transfert d’énergie du dendron conjugué donneur. Dans le premier chapitre, nous avons décrit la chimie des porphyrines en considérant surtout trois aspects: (i) structure, (ii) propriétés optiques et (iii) méthode synthétique. Nous avons également reporté les porphyrines préalablement étudiées dans notre groupe de recherche et proposé de nouveaux modèles lors de cette thèse. Dans le deuxième chapitre, nous avons étudié l’influence de la position de substitution du phényle sur le coeur central qui est la porphyrine TPP. Deux groupes de nouveaux dendrimères ont été synthétisés avec différentes positions de substitution du phényle de la TPP: série parasubstituée TPP1, TPP2 et TPP3, et série méta-substituée TPP4, TPP5 et TPP6. Ces dendrimères ont tous des dendrons conjugués avec des ponts phényl-alcynes et des groupements fluorènyles terminaux. Dans le troisième chapitre, pour étudier l’influence des antennes périphériques, une série de dendrimères de porphyrine à base de TFP avec différentes positions de fluorènyles dans les dendrons conjugués (fluorényle central, fluorényle pontant et fluorényle terminal): TFP1, TFP2 et TFP3 a été synthétisée. Le fluorényle central influence principalement l’émission et le rendement quantique, alors que le fluorényle ponté et le fluorényle terminal ont un plutôt un effet sur l’absorption et l’émission du dendron en raison du transfert d’énergie prenant effet. Pour le plus gros dendrimère TFP3, lors de l’excitation du dendron, une émission résiduelle lors du processus de transfert est observée due à une trop grande distance entre ce chromophore et le coeur de la porphyrine. Dans le quatrième chapitre, afin d’étudier l’influence des connexions dans le dendron, deux nouveaux dendrimères de porphyrine incorporant des ponts vinyles et alcynyles, TPP-D et TFP-D, ont été synthétisés et comparés aux analogues avec des ponts alcynes TPP-T et TFP-T. Ces ponts avec des doubles liaisons influencent dans une certaine mesure les propriétés optiques des dendrimères de porphyrine en fonction des positions occupées. Dans le dernier chapitre, deux oligomères (un dimère linéaire et en un trimère en étoile), ont été synthétisés à partir du même monomère de porphyrine avec TFP comme groupement terminauxDuring this thesis, we have worked on the synthesis and characterization of new compounds using the porphyrin macrocycle as a starting material. The aim, after synthesis, was to study the photophysical properties of these new molecules. More precisely, we have synthesized and characterized three groups of fluorenyl-porphyrin dendrimers and two oligomers in conjugated structures. Their correlation on optical property-structure have been discussed in detail, as well as the energy transfer processes from the conjugated dendron donor to porphyrin acceptor. In the first chapter, we introduce the general background of the porphyrin chemistry based on three aspects: (i) structure, (ii) optical properties and (iii) synthetic methods. We further review prior porphyrin studies done in our group and propose new molecular designs based on these results. In the second chapter, we study the influence of substitution position and nature of the antennae on the central core. Two groups of new TPP-cored porphyrin dendrimers were synthesized according to different substituted positions on the peripheral phenyl rings: para-substituted series TPP1, TPP2 and TPP3, and meta-substituted ones TPP4, TPP5 and TPP6. All have conjugated dendrons with bridged phenyl-alkynyl and are terminated by fluorenyl groups. In the third chapter, we study the influence of positions of light absorbers. To this aim, a series of TFP-cored porphyrin dendrimers presenting fluorenyls in conjugated dendrons on different positions is reported (core fluorenyl, bridging fluorenyl and terminal fluorenyl): TFP1, TFP2 and TFP3. The core fluorenyl mainly influences emission peaks and quantum yield, while the bridging fluorenyl and terminal fluorenyl have a large effect on the dendron absorption and on the energy transfer efficiency. Thus, for the largest dendrimer TFP3, dendron emission is not totally quenched by long distance energy transfer process when exciting the peripheral dendrons. In the fourth chapter, we study the influence of linkages in the Dendron. Thus, two new porphyrin dendrimers with bridged vinyl, TPP-D and TFP-D, were synthesized and compared to analogues with alkynyl bridged TPP-T and TFP-T. Vinyl and alkynyl bridges are shown to influence the optical properties of the porphyrin dendrimers to a certain extent depending on the substituted positions. Finally, in the last chapter, two oligomers with n-butyl substituted TFP as terminal group, a linear dimer and a star – shaped trimer, were synthesized from the same porphyrin monomer
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Anderson, Sally. "Templated synthesis of porphyrin oligomers." Thesis, University of Cambridge, 1993. https://www.repository.cam.ac.uk/handle/1810/251546.
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Conroy, M. "Synthesis of #alpha#, #omega# functionalised oligomers." Thesis, Lancaster University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240508.
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Schneider, Stephen Edward. "Guanidinium linked oligomers : design, synthesis, and applications /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Hao, Yu, and 郝宇. "Synthesis and conformational studies of beta 2,3-cyclic aminoxy peptides." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B36363236.
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Crase, Jason L. "Synthesis and Characterization of Ortho-Phenylene Oligomers." Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1282931679.
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Yang, Wenwen. "Synthesis of N-alkyl urea peptoid oligomers." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378197097.
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Benlahouès, Antoine. "Développements de méthodologies de synthèse innovantes pour l'obtention de chimiothèques de polyélectrolytes multifonctionnalisés." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1063/document.
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Les polyélectrolytes sont des polymères chargés, solubles dans l'eau, omniprésents dans les nature et capables d’interagir avec de nombreux composants cellulaires. Leur utilisation dans des essais cliniques est actuellement limitée par le manque de données fiables sur les relations entre leurs structures et leurs biopropriétés. Ce projet s'inscrit dans un programme plus vaste visant à obtenir une bibliothèque de polyélectrolytes multifonctionnalisés bien caractérisés pour le criblage de biopropriétés. Dans ce cadre, nous avons cherché à synthétiser des chaînes macromoléculaires contenant des unités maloniques C(COOH)2 situées à différentes positions le long du squelette du polymère. Ces unités peuvent être utilisées comme points de départ pour introduire plusieurs autres groupes fonctionnels en utilisant de nombreuses réactions de la chimie organique, conduisant à un grand nombre de structures à partir d'un squelette commun, y compris des copolymères. Cette thèse est schématiquement divisée en quatre parties : (a) une présentation bibliographique des relations existant entre structures et propriétés pour des polymères multifonctionnalisés, suivie d'une analyse plus spécifique de l'importance du positionnement d’esters carboxyliques le long d’une chaîne carbonée, (b) une description des efforts expérimentaux menés pour obtenir les poly(triméthylène-1,1-dicarboxylate)s, des intermédiaires clés dans la synthèse des polymères décrits dans les chapitres suivants, (c) une description de l'hydrolyse du précurseur ci-dessus, donnant l'acide poly(triméthylène-1,1-dicarboxylique), ainsi que des propriétés et de la réactivité de ce polyacide, (d) un rapport détaillé sur la synthèse de l’acide poly(triméthylène carboxylique) par décarboxylation quantitative du polyacide ci-dessus, ainsi que sur les propriétés et réactivité de ce polyacide. Dans les deux dernières sections, un accent particulier est mis sur la portée et les limites de diverses procédures de post-fonctionnalisation lorsque l'on tente d'obtenir une bibliothèque de polymères fonctionnels à partir de précurseurs polycarboxyliquesPolyelectrolytes are water-soluble charged polymers that are ubiquitous in life science and capable of interacting with many cellular constituents. Their use in clinical trials is currently limited by a lack of reliable data on the relationships linking their structures to bioproperties. This project is part of a larger program aimed at obtaining a library of well-characterized multifunctionalized polyelectrolytes for the screening of bioproperties. In this framework, we aimed at synthesizing macromolecular chains containing malonic units C(COOH)2 located at various positions alongside the polymer backbone. These units can be used as starting points to introduce several other functional groups using many reactions from organic chemistry, leading to a great number of structures from a common skeleton, including copolymers. This thesis is schematically divided into four parts: (a) a bibliographical presentation of the relationships existing between structures and properties for multifunctional polymers, followed by a more specific analysis on the importance of carboxylic esters positioning alongside a carbon chain backbone, (b) a description of experimental efforts aimed at obtaining poly(trimethylene-1,1-dicarboxylate)s, key intermediates in the synthesis of a large family of polymers described in the next chapters, (c) a depiction of the hydrolysis of the above precursor, yielding poly(trimethylene-1,1-dicarboxylic acid), as well as of the properties and reactivity of this polyacid, (d) a detailed report on the synthesis of poly(trimethylenecarboxylic acid) via the quantitative decarboxylation of the above polyacid, as well as of the properties and reactivity of this polyacid. A special focus is made in the last two sections on the scope and limitations of various post-functionalizing procedures when attempting to obtain a large library of functional polymers from polycarboxylic precursors
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Royappa, Martin. "Novel Organophosphorus Oligomers. Synthesis and conformation of ¿-hydroxy phenylphosphinates." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/5748.
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Chapter one reviews the recent progress in the synthesis of phosphonopeptides, pseudopeptides containing a phosphinic, phosphonic or phosphonamide linkage in place of an amide (peptide) linkage. It describes some of the general methods for the synthesis of these pseudopeptides; for example through couplings to the nitrogen of an ¿-aminophosphonic acid, or Michael addition to acrylates, as well as other methods, the scope for which are not as wide yet. It also provides a summary of the reported biological activities of this class of pseudopeptides.
Chapter two contains the results and discussion for a novel method for the synthesis of ¿-hydroxy phenylphosphinate oligomers as well as hybrid oligomers containing ¿-hydroxy phenylphosphinic acid and ¿-amino carboxylic acids. In particular, synthesis of a series of dimeric ¿-hydroxy phenylphosphinates are reported. The analysis of these dimers by a combination of NMR spectroscopy, X-ray crystallography and computational methods shows intramolecular hydrogen bonding in these molecules depends on the relative configuration of the carbon and phosphorus atoms. However, although the development of the synthetic methods was successful, the separation and isolation of the diastereomers was not always possible, which hindered a more comprehensive analysis of folding patterns in these molecules.
Chapter three contains the experimental procedures, preparation and spectroscopic characterisation of all the chemical compounds.
Crystal data and details of crystal structures are in the Appendix.EPSRC
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Allared, Fredrik. "Synthesis of new building blocks for conjugated oligomers." Doctoral thesis, KTH, Chemistry, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3782.
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This thesis deals with the synthesis of new organicmaterials for electronic applications. Several new ring-formingmethods are employed to construct sulphur heterocycles: Tandemelectrophilic aromatic substitution and acid-catalyzedtransetherification of methoxythiophene, double electrophilicaromatic substitutions with ethane-1, 2-disulphenyl chloride,and also, the reaction of dienes with sulphur dichloride. Twonew condensed thiophenes have been incorporated in end-cappedoligothiophenes. An improvement of the synthesis of [3,2-b:2, 3-d]thiophene is reported, with some attempts toincorporate it in oligomers. A synthesis of substitutednaphthalenes is also described. A new method of producingdisubstituted thiophenes from substituted butadienes anssulphur dichloride is employed in a new route to 3, 4-ethylenedioxythiophene, a very important monomer for conductingpolymers.
Keywords :Organic Semiconductors, Thiophenes,Heterocyclic Synthesis, Dithienothiophene, Naphthalene,Ethylenedioxythiophene
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Haywood, Rachael. "Synthesis of telechelic oligomers for potential new materials." Thesis, Lancaster University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404263.
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Hoong, Seng Soi. "Synthesis of oligomers/polymers from plant oil derivatives." Thesis, University of Warwick, 2013. http://wrap.warwick.ac.uk/57716/.
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The work presented in this thesis represents the chemical modifications of unsaturated plant oils to yield oligomeric/polymeric polyols suitable for polyurethane synthesis. Chapter 1 provides the introduction to the chemistry of polyurethanes, plant oils and plant oil based polyols. Chapter 2 focus on making oligomeric polyols from unsaturated plant oils through epoxidation and subsequent epoxide ring opening oligomerization that yielded oligomeric polyols. The properties of these oligomeric polyols were influence by the level of unsaturation of the plant oils. In addition, catalyst loading, monomer concentration and reaction time play vital role in determining the properties of the oligomeric polyols. Plant oil based polyols were also prepared by epoxide ring opening with renewable polyhydric alcohols that provide a variety of plant oil based polyols for polyurethane synthesis. Chapter 3 focus on the synthesis of polyurethanes (PU) from various types of plant oil based polyols as well as the evaluation of the mechanical properties of these synthesized PU. The tensile test of the PU shows that the mechanical properties were related to the structure and functionalities of the plant oil based polyols. The bulk of Chapter 4 discusses the copolymerization of epoxidized plant oils with tetrahydrofuran and the use of these copolymers for the synthesis of PU. The properties of the copolymers were related to the epoxidized oils used in the reaction and therefore influence the mechanical properties of the PU synthesized from them. Finally, Chapter 5 is a collection of work on the one-pot oligomerization of unsaturated fatty acid and plant oils with and without catalyst as well as the synthesis of PU based on these polyols.
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Tan, Biao. "Synthesis and characterization of phenylethynyl endcapped polyetherimide oligomers." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/40330.
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Eldridge, David Lewis. "Synthesis and Characterization of Cyclic Arylene Ether Oligomers." W&M ScholarWorks, 1996. https://scholarworks.wm.edu/etd/1539626044.
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Hao, Yu. "Synthesis and conformational studies of beta 2,3-cyclic aminoxy peptides." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B36363236.
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Li, Wei, and 李巍. "Peptides of Alpha-Aminoxy acids: novel secondary structures and applications as selective chloridereceptors." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B44570132.
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Chen, Fei, and 陳飛. "Studies on aminoxy peptides and prebiotic peptide formation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B38534149.
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Al-Aeeb, Ahmed. "The synthesis of 1-butene oligomers with vinyl endgroups and their use in further reactions." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/379.
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Shields, Carl Monroe. "The synthesis and characterization of maleimide-endcapped imide oligomers." Case Western Reserve University School of Graduate Studies / OhioLINK, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=case1054829455.
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Durand, Nelly. "Synthèses de nanoparticules fluorées pour application dans les revêtements." Thesis, Montpellier, Ecole nationale supérieure de chimie, 2010. http://www.theses.fr/2010ENCM0003.
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Cette thèse s'inscrit dans le cadre d'un projet de l'Agence National de Recherche (ANR) dans lequel participent deux sociétés et deux laboratoires universitaires. L'objectif de ce projet consiste à améliorer les propriétés mécaniques (résistance à l'abrasion) et thermiques (température de dégradation) de revêtements fluorés antiadhésifs en y intégrant des nanoparticules de silice. Or, la silice est une charge hydrophile qui se disperse difficilement dans une matrice fluorée. C'est pourquoi nous avons envisagé de modifier sa surface avec des réactifs fluorés, et la nature des divers précurseurs a une influence sur l'amélioration de la dispersion des nanoparticules. Ainsi, nous avons, dans un premier chapitre, étudié la miscibilité et la compatibilité des polymères fluorés entre eux. Les polymères fluorés sont réputés pour leur inertie chimique, hydrophobie et leurs propriétés thermiques très avantageuses. Mais les très bonnes propriétés des polymères fluorés entraînant parfois des difficultés de mise en œuvre, nous avons choisi de travailler avec deux copolymères fluorés, le poly(TFE-co-HFP), un copolymère statistique à base de tétrafluoroéthylène (TFE, -CF2-CF2-) et d'hexafluoropropène (HFP, -CF(CF3)-CF2-) voisin du PTFE utilisé pour les revêtements, et le poly(VDF-co-HFP), un copolymère composé de fluorure de vinylidène (VDF, -CH2-CF2) et d'hexafluoropropène. Ils présentent de bonnes propriétés et sont faciles à employer à l'état fondu de par leurs faibles températures de fusion (respectivement de 140 et 275°C pour le poly(VDF-co-HFP) et le poly(TFE-co-HFP)). Des mélanges binaires à l'état fondu ont été réalisés puis caractérisés entre ces deux copolymères semi-cristallins mais également avec un polyéther fluoré, composé de plusieurs unités d'oxyde d'hexafluoropropène (HFPO, -CF(CF3)CF2O-) totalement amorphe. Les résultats obtenus suite à ces mélanges ont indiqué les trois types de précurseurs fluorés à employer lors des modifications de surface et ce en fonction de la matrice fluorée : composés à base de TFE (-CF2-CF2-), de VDF (-CH2-CF2-) et de l'HFPO (-CF(CF3)CF2O-). Ainsi, le second chapitre est consacré aux stratégies de synthèse de ces précurseurs fluorés contenant des motifs VDF et HFPO. Deux méthodes de polymérisation ont été réalisées : 1) La polymérisation radicalaire par transfert d'iode (ITP) du VDF conduisant à CnF2n+1-[CH2-CF2]m-I ; 2) La polymérisation anionique par ouverture de cycle de l'HFPO permettant la synthèse C3F7O-[CF(CF3)CF2O]-CF(CF3)-COX avec X : groupements fonctionnels. Ces produits ont été caractérisés par spectroscopies RMN du 19F et du 1H, IR, GPC, DRX, ATG et DSC. Les oligomères du TFE (CnF2n+1-I ou CnF2n+1-C2H4-SH avec n= 4 ou 6) n'ont pas été préparés du fait des risques encourus lors de la manipulation du TFE (gaz explosif). Après leurs synthèses, fonctionnalisations et caractérisations, nous les avons greffés à la surface de silices submicroniques. La principale méthode de greffage employé est le « grafting onto » qui permet de modifier la surface des particules inorganiques avec des macromolécules (oligomères ou polymères) et le troisième chapitre présente trois méthodes de greffage : 1) L'addition radicalaire de RFI ou RFC2H4SH sur une double liaison (vinylique ou allylique) ; 2) La condensation d'un oligomère à base d'HFPO fonctionnalisé ester méthylique sur une silice possédant des fonctions amine ; 3) La méthode la plus communément, utilisée l'hydrolyse-condensation, à partir d'oligo(HFPO) fonctionnalisés alkoxysilane. Les méthodes d'analyses employées afin de caractériser ces nanohybrides fluorés sont les spectroscopies RMN 1H et 29Si à l'état solide, IR, les analyses élémentaires et thermogravimétriques. Nous avons utilisé ces différentes stratégie de modifications de surface afin d'obtenir une large gamme de silices modifiées avec des groupements fluorés tout en tenant compte de la miscibilité des chaînes fluorées entre elles (Chapitre 1)This thesis is part of a project of the National Research Agency (ANR) which involved two companies and two university laboratories. The objective of this project is to improve the mechanical properties (abrasion resistance) and thermal (degradation temperature) nonstick fluorinated coatings by incorporating silica nanoparticles. However, silica is a hydrophilic filler which is hardly dispersed in a fluoridated matrix. Therefore, we planned to modify its surface with fluorinated reagents, and the nature of various precursors has an influence on improving the nanoparticles dispersion. Thus, we, as a first chapter, studied the miscibility and compatibility of the fluoropolymers. Fluoropolymers are known for their very attractive properties like chemical inertness, hydrophobicity and thermal. But these very good properties of fluoropolymers sometimes cause difficulties application, we chose to work with two fluorinated copolymers, poly (TFE-co-HFP), a copolymer based on tetrafluoroethylene (TFE,-CF2-CF2-) and hexafluoropropylene (HFP,-CF(CF3)-CF2-) neighbor of PTFE used for coatings, and poly (VDF-co-HFP), a copolymer composed of vinylidene fluoride (VDF, -CH2-CF2) and hexafluoropropylene. They have good properties and are easy to use in blend due to their low melting temperatures (140 and 275° C for poly (VDF-co-HFP) and poly (TFE-co-HFP), respectively). Blends have been realized and characterized between two semi-crystalline copolymers but also with a fluorinated polyether composed of several units of hexafluoropropylene oxide (HFPO,-CF(CF3)CF2O-) which is completely amorphous. The results obtained from these blends indicated that the three types of precursors can be used for fluorinated surface modifications and in function of the fluoropolymer : compounds are based on TFE (-CF2-CF2-), VDF (-CH2-CF2-) and HFPO (-CF(CF3)CF2O-). Thus, in the second chapter, the synthesis of these fluorinated precursors containing VDF and HFPO units are shown for this, two polymerization methods were carried out : 1) The iodine transfer polymerization (ITP) of VDF ; 2) The anionic polymerization by ring opening of HFPO. These products were characterized by 19F and 1H NMR spectroscopy, FTIR, GPC, XRD, TGA and DSC. Oligomers of the TFE (CnF2n+1-I or CnF2n+1-C2H4-SH with n = 4 or 6) have not been prepared because of the risks incurred during the handling of TFE (explosive gas). After their synthesis, functionalization and characterization, we have grafted them on the surface of silica nanoparticles. The main method used is the "grafting onto" which allows to modify the surface of inorganic particles with macromolecules (oligomers or polymers) and the third chapter presents three methods of grafting : 1) The radical addition of RFI and/or RFC2H4SH on a double bond (vinyl or allyl) ; 2) The condensation of an oligomer based HFPO functionalized methyl ester on a silica with amine functions ; 3) The most commonly used hydrolysis-condensation, using oligo (HFPO) functionalized alkoxysilane. The analysis methods used to characterize these fluorinated nanohybrids are the 1H and 29Si solid state NMR, FTIR, elemental and thermogravimetric analysis. We used these different surface modification to obtain a wide range of modified silica with fluorinated groups. After their characterization, these fluorinated silica are introduced by blend into two fluorinated matrices poly (VDF-co-HFP) and poly (TFE-co-HFP). The fourth is dedicated to the study of nanocomposite poly (VDF-co-HFP) / silica. Initially, a state of the art is presented as this type of composite has been widely discussed in the literature contrary to nanocomposites poly (VDF-co-HFP) or poly (TFE-co-HFP) with fluorinated nanoparticles
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Lo, Pik Kwan Peggy. "Synthesis and structure-property relationships of novel multi-[pi] conjugated molecular systems." HKBU Institutional Repository, 2006. http://repository.hkbu.edu.hk/etd_ra/704.
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Thamyongkit, Patchanita. "Synthesis and characterization of pyrazine and phthalocyaninatonickel(II) substituted PPV analogous oligomers Synthese und Charakterisierung von Pyrazin- und Phthalocyaninatonickel(II)-substituierten PPV-anologen Oligomeren /." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963899929.
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Rahbarnia, Shohreh. "Synthesis and properties of helical oligothiophenes and molecular gyroscopes." Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3359908.
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Thesis (Ph. D.)--University of California, Riverside, 2009.Includes abstract. Title from first page of PDF file (viewed Jan. 29, 2009). Includes bibliographical references. Issued in print and online. Available via ProQuest Digital Dissertations.
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Kwok, Chi Chung. "Synthesis and characterization of novel series of light-emitting oligomers." HKBU Institutional Repository, 2001. http://repository.hkbu.edu.hk/etd_ra/295.
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Tokuji, Sumito. "Synthesis of New Porphyrin Oligomers Utilizing β-Functionalization Reactions." 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/175146.
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Tetzlaff, Charles N. "Synthesis and evaluation of acylated DNA and RNA oligomers /." Thesis, Connect to Dissertations & Theses @ Tufts University, 2001.
Find full textAbstract:
Thesis (Ph.D.)--Tufts University, 2001.Adviser: Clemens Richert. Submitted to the Dept. of Chemistry. Includes bibliographical references (leaves 228-235). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Forsythe, W. Graham. "The synthesis and transformation of novel lignin model oligomers." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675451.
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Lignin is a complex, interlinked, non-repeating, heterogeneous bio-polymer found in wood which consists of phenylpropane subunits. The phenolic monomers of lignin are linked via various ether and carbon-carbon bonds. It is the second most abundant biopolymer after cellulose, accounting for 15-30 % of biomass and it has the potential to be a renewable source of small aromatic feedstock molecules. The synthesis of lignin model compounds plays an important role in both the elucidation of lignin's structure and in modelling the conditions required for the production of valuable feedstock molecules from lignin depolymerisation. The aim of the research presented in this thesis has been to provide an efficient route to multi-gram quantities of lignin model compounds which are more representative of lignin than the low molecular weight models typically employed in previously published work. The syntheses of several hexameric lignin models as well as an octamer, all of which contain three of the most common linkages in the native polymer have been carried out. The synthetic methodology used improves upon existing methods of preparing higher molecular weight lignin models in both overall yield and efficiency as well as practically on a multi-gram scale. Several of these compounds were then subjected to published procedures aimed at the transformation of lignin and model compounds into added value fine chemical intermediates. Extensive analysis of the major products was performed leading to some preliminary mechanistic insights into lignin oxidative and reductive depolymerisation chemistry.
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Nahi, Riyadh. "Synthesis and biophysical studies of nucleic acid-binding oligomers." Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/97207/.
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In general, this thesis describes the design, synthesis, oligomerization and biophysical studies of novel PNA monomers. Our initial aim was to develop an efficient and inexpensive route for the synthesis of a series of novel alkyne PNA monomers bearing thymine, cytosine, adenine and guanine nucleobases suitable for Fmoc solid phase PNA synthesis strategy. These novel monomers allow functionalising the PNA sequences with alkyne functions at their Nterminus during solid phase synthesis. These novel monomers can be exploited in the click reaction applications such as a click ligation of PNA and conjugation of PNA with different substrates such as nucleic acids and proteins. As an application for ligation PNA sequences, the alkyne thymine PNA monomer was incorporated successfully into the target PNA oligomers during oligomerization. Mimicking the click (CuAAC) reaction linkers of the ligation of PNA oligomers, three novel 1,2,3-triazole functionalised building blocks were designed and prepared suitable for the Fmoc solid phase PNA synthesis strategy. Furthermore, synthesis of these building blocks specifically that is bearing thymine base represents an attempt for modification the original PNA oligomers in order to improve their drawbacks such as poor water solubility and cellular uptake or to enhance their hybridization properties. Our approach to synthesise these monomers is the Click (CuAAC) reaction which is not analogous for the routes that are used for the synthesis of the modified or unmodified PNA monomers. To investigate their effect on the biophysical properties of PNA oligomers, a single monomeric unit of these monomers was incorporated successfully into a series of mixed purine-pyrimidine 8-mer PNA sequences following the standard Fmoc-solid phase PNA synthesis conditions. In general, The Tm experiments-UV spectroscopy showed that the modified PNA oligomers containing these modified monomers still have a binding affinity with complementary sequences of DNA and RNA. The Tm values indicated that the incorporation of the 1,2,3-triazole functionalised monomers maintained or slightly reduced the thermal stability of the PNA/DNA duplexes, whereas the PNA/RNA duplexes resulted in a significantly reduced thermal stability. All of them are compared to the corresponding unmodified PNA/DNA duplexes.
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Krippner, Lorely Vivienne. "Synthesis and chemistry of hematoporphyrin derived monomers and oligomers /." Title page, table of contents and abstract only, 1991. http://web4.library.adelaide.edu.au/theses/09PH/09phk9228.pdf.
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Chan, Kwok-wai Queenie, and 陳幗慧. "Synthesis and photophysical properties of oligo (arylene-ethynylene)s,osmium(II) diimine and platinum(II) calix[4] arene complexes and theirapplications as sensory materials." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40988107.
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Screen, Thomas E. O. "The synthesis and properties of conjugated porphyrin oligomers and polymers." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393463.
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Turner, David James. "Novel solid phase approaches towards the synthesis of heterocyclic oligomers." Thesis, University of Sheffield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401182.
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Johnson, Paul D. "Nylon-6.6 oligomers : synthesis, characterization & relevance to the polymer." Thesis, Sheffield Hallam University, 1995. http://shura.shu.ac.uk/19878/.
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The primary aim of this work is the investigation of potential routes for the synthesis of selected oligomers of nylon-6.6 and trial syntheses using these routes. Once a general synthetic route to pure oligomers is available it can be applied to the preparation of oligomers of increasing length, while maintaining purity for future characterization studies. It was soon found that the "nylon intermediates" are not readily amenable to the reaction conditions involved in more conventional syntheses due to solubility, lability etc. Because of this the project rapidly developed into a series of problem solving episodes. Although the project was intended only to deal with integer oligomers problems concerning the protecting groups arose. A new direction was temporarily taken involving the synthesis of non-integer oligomers. Here the need for selective deprotection was no longer a factor as chain-growth products would have identical end groups. With no satisfactory method for selective removal of the carbobenzoxy group, the doubling reactions on integer oligomers had to be carried out using unprotected andN-protected monomers. The presence of these two products in the synthesis of the dimer could obviously lead to over reaction. However in the mixed anhydride reaction the acid end group on the N-protected monomer is activated prior to the addition of the unprotected monomer thus eliminating, or certainly reducing, this potential problem. The scheme was successfully taken up to a D.O.P. of eight although the purity of the octamer was lower than would have been liked. IR, MS, NMR and GPC were used throughout the synthetic work to determine the purity and identity of each product.
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Dunson, Debra Lynn. "Synthesis and Characterization of Thermosetting Polyimide Oligomers for Microelectronics Packaging." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/27394.
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A series of reactive phenylethynyl endcapped imide oligomers has been prepared in either fully cyclized or amic acid precursor form. Soluble oligomers have been synthesized with controlled molecular weights ranging from 2- to 12 Kg/mol. Molecular weight characterization was performed using SEC (size exclusion chromatography) and 13C-NMR, revealing good agreement between the theoretical and experimental (Mn) values. Crosslinked polyimides were obtained by solution or melt processing the oligomers into films and gradually heating in a programmed temperature manner up to the appropriate reaction temperature for the phenylethynyl groups, which is approximately 350-400°C. Thermal analysis of the resulting films showed high glass transition temperatures (>300°C) and excellent thermal stability, comparable to those found for thermoplastic control polyimides. The crosslinked films also had exceptional solvent resistance as evidenced by a high gel fraction (greater than or equal to 95%) following extraction in common solvents for several days. This was in contrast to the amorphous thermoplastic controls, which quickly dissolved upon immersion in solvents.
The monomers used for synthesizing the polyimide oligomers were varied systematically within the series to study the influence of both molecular structure and molecular weight on the physical and film-forming properties. The incorporation of fluorinated monomers, such as 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), reduced water absorption and lowered the dielectric constant relative to non-fluorinated polyimides in the series. When flexible ether linkages were incorporated in the repeat unit by using 4,4'-oxydianiline (ODA), relatively more ductile solvent-cast films were obtained from oligomers having Mn values as low as 10 Kg/mol. Additionally, oligomer Mn and the relative rigidity/symmetry of the repeat unit structure greatly influenced the solubility of polyimides in NMP. For example, even 6FDA/p-phenylenediamine based oligomers with Mn values targeted below 10 Kg/mol precipitated from NMP at 180°C during solution imidization.
The relationship between solution viscosities of polyimide and poly(amic acid) thermosetting oligomers and wetting/spreading ability to form continuous films during spin casting was elucidated. Employing o-dimethoxybenzene (DMB) as a cosolvent with NMP improved the film-forming ability of the fully imidized 6FDA/ODA oligomer series. This was evidenced by a decrease in viscosity (via suppression of physical-type gel formation) and better overall coverage and clarity of the films. Humidity was found to have a detrimental effect, causing the polyimide oligomers to phase separate to form cloudy or porous films. When moisture was reduced, oligomers having Mn greater than or equal to 6 Kg/mol formed spin cast films of <20 micrometer thickness with good qualitative adhesion to several inorganic substrates.
Dielectric constants (epsilon) were estimated for several of the polyimides by measuring the refractive indices (n) of the films and using Maxwell's relationship (epsilon at optical frequencies is equal to n raised to the second power). The apparent dielectric constants were low, ranging from 2.47 to 2.75.
The novel combination of low dielectric constant, solvent resistance and isotropic physical properties inherent in the thermosetting polyimide oligomers makes these materials excellent candidates for use as thin film insulating layers in microelectronics packaging applications.Ph. D.
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Jurek, Michael J. "Synthesis and characterization of poly(arylene ethers) and functionalized oligomers." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/80289.
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Molecular weight control and endgroup functionalization in poly(arylene ether sulfones) has been achieved by two synthetic routes. The first utilizes DMSO/sodium hydroxide and aminophenol to introduce the amine functionality. This route, though synthetically useful, suffers from serious limitations, such as hydrolytic side reactions and oxidation of the end capping reagent. An alternative route utilized K₂CO₃/NMP as base and solvent respectively. This approach has been used with great success in the preparation of both high molecular weight polymers and functionalized oligomers. We have extended this method to include amine terminated oligomers through the use of a novel aminophenolic compound 2-p-aminophenyl-2-p-hydroxyphenylpropane or MBA. The use of MBA to introduce terminal amine functionality allowed a simpler, 1-step synthesis of controlled molecular weight oligomers to be realized. Our investigations focused on bisphenol-A based systems, but this technique may be also utilized with other bisphenols.
The synthesis and characterization of a wide variety of derivatives of these functionally terminated oligomers was demonstrated. A number of potential post reactions involving these oligomeric diamines were investigated and synthetic techniques to prepare novel block and segmented copolymers were defined. As the molecular weight of the sulfone oligomer was varied, the percent sulfone character in a given polymeric material could be systematically changed. The effect was studied in block copolymers with poly(arnide sulfones) and in novel modified epoxy and bismaleimide thermosetting systems.Ph. D.
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Feng, Xinjiang. "Synthesis and characterization of functional [pi]-conjugated oligomers for multi-photon absorption." HKBU Institutional Repository, 2009. http://repository.hkbu.edu.hk/etd_ra/1097.
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Shotwell, Sandra Leigh. "Synthesis and Characterization of ortho-Phenyleneethynylenes and Diphenylamine Polymers." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10449.
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In the first part of this thesis, the synthesis, characterization and investigation of ortho-phenyleneethynylenes containing heterocycles, are presented. These compounds display changes in absorption and emission spectra varying with their functionalization and size. These compounds also have the ability to coordinate with metals. The synthesis of coordination compounds and their crystallographic data are reported. The synthesis and characterization of tetraethynyl thiophene compounds containing pyridines are also presented. These compounds exhibit differences in absorption and emission spectra upon exposure to various metal salts. The final topic to be discussed is the synthesis and characterization of diphenyl amine polymers. These polymers could in principle be used in NLO applications or light emitting devices.
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Zhang, Ting, and 张婷. "Amphiphilic peptides containing alternating α-aminoxy acids and α-amino acids to mimic the α-helix of bak BH3 domain and disulfide bondas covalent linkage for stabilizing 7/8 helix." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47869409.
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The binding between the survival protein Bcl-xL and the death-promoting region of
the Bcl-2-related protein Bak is one of the key protein-protein interactions in the
regulation of programmed cell death (apoptosis). Since it is well recognized that the
BH3 domain of Bak adopts an amphipathic α-helix to interact with Bcl-xL through
hydrophobic and electrostatic effects, conformational studies and possible
applications of the α-aminoxy acid-containing peptides as mimics of the α-helix of
Bak BH3 domain have been carried out. The main results are summarized below.
Four short peptides ZT1?ZT4 containing alternating α-aminoxy acids/α-amino acids
as the mimics of the α-helix of Bak protein were designed and synthesized. However,
none of these four peptides, at the concentration of 25 μM, exhibited a significant
inhibitory effect on the Bcl-xL inhibition test. Circular dichroism spectroscopic
studies on ZT1?ZT4 as well as short model peptides N-minus, N-plus, C-minus and
C-plus suggest that the proposed secondary structure, the 7/8 helix, is not stable in
aqueous solutions.
1H NMR, 2D NMR and circular dichroism spectroscopic studies on the disulfide
bond-constrained short peptides 4.7?4.9 with alternating α-aminoxy acids and
α-amino acids suggest that a disulfide linker with three methylene units between
adjacent α-amino acid residues could dramatically increase the stability of the 7/8
helix even in a mixed buffer/methanol solution.
1H NMR, 2D NMR and circular dichroism spectroscopic studies have also revealed
that the hybrid soluble peptides C-free, N-free and Both-free containing α-amino
acids and β-2,2-cyclopropyl-amino acids adopted a stable 8/8 helix in aqueous
solution.published_or_final_version
Chemistry
Doctoral
Doctor of Philosophy
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Lim, Christina Go. "Synthesis and characterization of poly(oxazoline) rotaxanes and literature review on separation, detection and identification of cyclic oligomers in poly(ethylene terephthalate) and poly(c̋aprolactam) /." This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-01202010-020257/.
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Jagtap, Subodh Prakash. "Design and synthesis of and π-stacked conjugated oligomers and polymers." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/47574.
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Interchain interactions between π-systems have a strong effect on the properties of conjugated organic materials that find application in devices such as light emitting diodes (OLEDs), organic photovoltaics (OPVs), and field effect transistors (FETs). We have prepared covalently-stacked oligo(1,4-phenylene ethynylene)s and oligo(1,4-phenylene vinylene)s to study the influence of chain-chain interactions on the electronic structure of closely packed conjugated units. These serve as models for segments of conjugated materials in thin film devices. Extension of this concept has allowed us to prepare multi-tiered systems that display the influence of pi-stacking. The stacked architectures were prepared by multi-step synthesis of the scaffolds, followed by metal-catalyzed cross coupling reactions (Sonogashira, Heck, Suzuki couplings) to incorporate the conjugated oligomers. The optical and electrochemical properties of these stacked compounds and polymers were compared to their unstacked linear counterparts. These studies provide a platform for the exploration of the nature of charge carriers and excitons in a broad class of materials that have significant potential in addressing challenges in power generation, lighting and electronics.
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O'Dell, Richard. "The synthesis of polymers via the linkage of functionally terminated oligomers." Thesis, Lancaster University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306046.
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