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Zou, Yu. "Dendrimères et dendrons phosphorés : synthèse, propriétés et applications en nanomédecine." Electronic Thesis or Diss., Université de Toulouse (2023-....), 2024. http://www.theses.fr/2024TLSES093.
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L'objectif de ce travail de thèse a été de préparer de nouveaux dendrimères ou dendrons phosphorés, qu'ils soient neutres, cationiques ou anioniques, dans le but d'élargir le panel des applications dans le domaine de la nanomédecine en tant que molécules actives par elles-mêmes ou en association avec certains médicaments. Au chapitre 1, la synthèse d'un nouveau dendrimère phosphoré polycationique comportant en surface 5 groupements pyrrolidinium et une amine protonnée a été menée à bien. Ce dendrimère associé au microRNA-30d permet d'obtenir des polyplexes qui sont transférés dans les cellules cancéreuses. Il a également un bon effet thérapeutique sur les cellules cancéreuses du sein. Au Chapitre 2, l'objectif était de développer un système de délivrance de médicaments capables de pénétrer les lésions cérébrales pour proposer un traitement de la maladie de Parkinson. Pour cela, il a été mis au point la formation d'un nanocomplexe formé d'un dendrimère phosphoré porteur de groupements hydroxyl en surface, combiné avec la fibronectine, qui règle la prolifération et la différenciation et la motilité cellulaire. Sur un modèle murin de la maladie de Parkinson, il a été mis en évidence une pénétration efficace au niveau de la BBB (blood brain barrier) de l'assemblage dendrimère phosphoré AK-123 et fibronectine exerçant une activité anti-inflammatoire et antioxydante permettant de soulager efficacement les symptômes observés et démontrant le grand potentiel pour un traitement clinique de la maladie de Parkinson mais aussi ouvrant un espoir de viser d'autres maladies neurodégénératives. Au Chapitre 3, les résultats obtenus dans le domaine de la maladie de Parkinson lors de l'action conjuguée d'un dendrimère phosphoré de génération 2 comportant 48 groupements hydroxy en surface et de la fibronectine nous ont incités à diversifier la nature et la structure de ces dendrimères afin d'avoir des premières indications de leur activité en général et d'aborder éventuellement une étude SAR (relation structure activité). Pour cela nous avons pu préparer tout un ensemble de nouveaux dendrimères phosphorés neutres de générations 1 et 2, caractérisés par des structures internes différentes de celles des dendrimères utilisés dans le chapitre précèdent, et de longues chaines en surface comportant également des groupements hydroxyle. Ces dendrimères ont l'avantage de posséder des groupements amines protonées permettant une solubilité en milieu aqueux. Nous avons pu également préparer des dendrons phosphorés neutres et chargés. Des résultats préliminaires concernant leurs propriétés ont pu être mis en évidence. Au Chapitre 4, Le but de notre étude a porté tout d'abord sur la synthèse de dendrimères phosphorés anioniques originaux et à l'utilisation d'un de ces dendrimères en l'occurrence le dendrimère AK 137 qui présente une activité anti-inflammatoire optimale et une grande aptitude pour la délivrance de protéines. Des nanocomplexes stables formés par ce dendrimère et diverses protéines en solution aqueuse (bovine serum albumin (BSA), ribonucleaseA (RNaA), ovalbumine (OVA) et fibronectine (FN) ont été obtenus. Nous avons pu démontrer que l'association AK-137@FN NCs bloque l'activation de certaines voies de signalisation (NF-kB et P13K/Akt), induit la polarisation de macrophages vers des phénotypes M2, inhibe la sécrétion de cytokines pro-inflammatoires (TNF-alpha, IL-1beta et IL6) et augmente les propriétés antioxydante de FN in vitro. Les effets thérapeutiques de l'association AK-137@FN ont été démontrés sur des modèles de souris ALI (acute lung injury) et AGA (acute gout arthritis) sans observation de toxicité systémiqueThe objective of this thesis work was to prepare new phosphorous dendrimers or phosphorous dendrons, either neutral, cationic or anionic, with the aim of broadening the range of applications in the field of nanomedicine as molecules active by per se. or in combination with certain medications. In Chapter 1, the synthesis of a new polycationic phosphorus dendrimer comprising 5 pyrrolidinium groups on the surface and a protonated amine was successfully completed. This dendrimer associated with microRNA-30d makes it possible to obtain polyplexes which are transferred into cancer cells in an optimal N/P ratio of 10. These polyplexes are cytocompatible and transfer miR-30d to suppress glycolysis associated with SLC2A1. The inhibition of the migration and invasion of murine cancer cells in vitro and in vivo were thus demonstrated. This dendrimer can be considered as an important component for therapy based on the use of miR-30d. In Chapter 2, we develop a drug delivery system capable of penetrating BBB (blood brain barrier) to provide treatment for degenerative disorders. For this, the formation of a nanocomplex was developed consisting of a phosphorus dendrimer carrying hydroxyl groups on the surface, combined with fibronectin, which regulates proliferation and differentiation and cell motility. In a mouse model of Parkinson's disease, effective penetration at the level of the BBB of the phosphorous dendrimer assembly AK-123 and fibronectin was demonstrated, exerting an anti-inflammatory and antioxidant activity allowing to decrease effectively the symptoms observed and demonstrating the great potential for clinical treatment of Parkinson's disease but also hold great promise to be used to tackle other neurodegenerative disorders. In Chapter 3, the results obtained in the field of Parkinson's disease during the combined action of a generation 2 phosphorous dendrimer comprising 48 hydroxyl groups on the surface and fibronectin have encouraged us to diversify the nature and structure of these dendrimers in order to have first indications of their activity in general and to possibly approach a SAR (structure activity relationship) study. According to these, we prepared a whole set of new neutral phosphorus dendrimers of generations 1 and 2, characterized by internal structures different from those of the dendrimers used in the previous chapter, incorporating long chains on the surface and also comprising hydroxyl groups. These dendrimers have the advantage of having protonated amine groups allowing solubility in an aqueous medium. We were also able to prepare neutral and charged phosphorous dendrons. Preliminary results concerning their properties have been demonstrated. In Chapter 4, the aim of this study was focused on the synthesis of original anionic phosphorus dendrimers and the application of these dendrimers, and particularly of the dendrimer AK 137 which presents optimal anti-inflammatory activity and great efficiency for the delivery of proteins. We demonstrate that the AK-137@FN NCs association blocks the activation of certain signalling pathways (NF-kB and P13K/Akt), induces the polarization of macrophages towards M2 phenotypes, inhibits the secretion of pro-cytokines. (TNF-alpha, IL-1beta and IL6) and increases the antioxidant properties of FN in vitro. The therapeutic effects of the AK-137@FN combination have been demonstrated in ALI (acute lung injury) and AGA (acute gout arthritis) mouse models without observation of systemic toxicity
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Prévôté, Delphine. "Synthese et reactivite de dendrimeres phosphores." Toulouse 3, 1997. http://www.theses.fr/1997TOU30214.
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Les dendrimeres sont des macromolecules geantes hyperbranchees construites selon un processus arborescent a partir d'un coeur central plurifonctionnel et comportant un grand nombre de fonctions terminales. Le premier chapitre de cette these consiste en une mise au point bibliographique sur les dendrimeres. Le travail personnel est reparti sur six chapitres. Le second chapitre decrit une nouvelle methode de synthese de dendrimeres phosphores. Le troisieme chapitre detaille la synthese d'un dendrimere a coeur fonctionnalise pouvant permettre l'acces a des dendrimeres de types segment block et layer block peu decrits dans la bibliographie. Le quatrieme chapitre, divise en deux parties, decrit dans un premier temps la methode de synthese de dendrimeres la plus performante mise au point au laboratoire. Ce dendrimere construit jusqu'a la douzieme generation possedent deux types de fonctions terminales : fonctions aldehydes et phosphore-chlore. La deuxieme partie de ce chapitre est consacree a l'etude de la reactivite des liaisons p-c1 terminales de ces dendrimeres qui nous ont permis de greffer des macrocycles en surface. La reactivite des fonctions aldehydes est etudiee dans les cinquieme et sixieme chapitres. Le cinquieme chapitre concerne plus precisement le greffage de fonctions organiques et bio-organiques telles que des esters, amines, acides et aminoacides, tandis que le sixieme chapitre detaille le greffage de groupements phosphores tels que les phosphonates, les phosphates, les phosphites et les ylures. Le septieme et dernier chapitre regroupe les parties experimentales des chapitres 2 a 6.
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Coleshill, Anita. "Synthesis of polyester dendrimers." Thesis, University of Warwick, 1998. http://wrap.warwick.ac.uk/55728/.
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Dendrimers are a fairly new class of macromolecule. They have many potential uses including use in surface coatings and as host molecules. There are two main methods available for constructing dendrimers, the convergent approach and the divergent approach. In this thesis dendrimers were synthesised using the divergent approach. In chapter one our original aim was to synthesise dendrimers based on bicine, but there were complications involved in synthesis and storage of the monomer. However, it was possible to make a iminium salt using bicine as the starting material, which was reacted with various nucleophiles. With 2,2-bishydroxymethylpropionic acid it was possible to produce a generation one protected dendrimer, but deprotection could not be achieved. In the third chapter the syntheses of dendrimers based on 4,4-bis(4- hydroxyphenyl)valeric acid are described. Dendrimers were successfully synthesised up to and including generation two. These were made using various esterification methods. Chapter four describes the synthesis of functionalised dendrimers. Generation one deprotected dendrimers were reacted with a variety of reagents to produce pent-4-enoyl, urethane and lineoyl functionalised dendrimers. Chapter five describes the analysis of dendrimers using MALDI-MS. For every dendrimer synthesis molecular weights were obtained well within the boundaries of experimental error. It was also shown how preparation time and laser power can affect the spectra obtained.
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Nyström, Andreas. "Dendrimers and dendronized polymers : synthesis and characterization." Doctoral thesis, KTH, Fiber- och polymerteknik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3970.
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The goal of this work was to synthesize complex macromolecular architectures such as dendrimers and dendronized polymers, and evaluate the effect from the dendrons on the optical and material properties. The work presented in this doctoral thesis, Dendrimers and Dendronized Polymers - Synthesis and Characterization, is divided into one minor and one major part. The first part deals with the synthesis and characterization of two sets of dendritic porphyrins based on 2,2-bis(methylol)propionic acid (bis-MPA). The second part deals with the synthesis and characterization of dendronized poly(hydroxyl ethyl methacylate), dendronized poly(norbornene), and dendronized triblock copolymers, were the pendant dendrons are based on bis-MPA. Both free-base and zinc containing dendritic porphyrins was synthesized up to the fifth generation by employing iterative ester coupling utilizing the acetonide protected anhydride of bis-MPA as generic building block. First and second generation dendron bearing methacrylates based on 2-hydroxyethyl methacrylate were also synthesized by utilizing the acetonide protected anhydride of bis-MPA, and subsequently polymerized by atom transfer radical polymerization. By adopting a divergent “graft-to” approach starting from the first generation dendronized poly(hydroxyl ethyl methacrylate), well-defined dendronized polymers with acetonide, hydroxyl, acetate and hexadecyl surface functionality were obtained. By utilizing the same divergent iterative esterfication, first to fourth generation dendron functionalized norbornenes were synthesized. These monomers were polymerized by ring-opening metathesis polymerization, utilizing either Grubbs´ first or second generation catalyst. Acrylate functional first to fourth generation monomers were synthesized by the copper(I) catalyzed “click” coupling of azido functional dendrons and propargyl acrylate. The monomers were polymerized to dendronized triblock copolymers by reversible addition-fragmentation chain transfer polymerization, utilizing a difunctional poly(methyl methacrylate) as macro chain transfer agent. The bulk properties of the dendronized poly(hydroxyl ethyl methacrylate) and poly(norbornene) were investigated by dynamic rheological measurements and differential scanning calorimetry. It was found that all the acetonide functional bis-MPA based dendronized polymers had glass transitions temperatures in a similar range. The rheological behaviour showed that for the dendronized polymers having the same backbone length the complex viscosity as a function of functionality was independent of the surface functionality of the polymer. The generation number of the polymer had a profound influence on the complex viscosity, changing form a Newtonian behaviour to a shear thinning behaviour when the generation of the dendrons was increased from two to four. The dendronized poly(norbornene) had increasingly shorter backbone lengths for each generational increase, and for the materials set with comparably lower degree of polymerization, the G’ part of the complex modulus was mostly affected by attaching larger dendrons. In the case of the sample set of higher degree of polymerization, the second, third, and fourth generation samples had similar slopes of the G’ and G” curves, indicating a similar relaxation behaviour.QC 20100914
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Nyström, Andreas. "Dendrimers and dendronized polymers : synthesis and characterization /." Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3970.
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Stoddart, Alison. "Synthesis, characterisation and properties of novel dendrimers." Thesis, Durham University, 2002. http://etheses.dur.ac.uk/4153/.
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A new family of aliphatic, polyurethane dendritic macromolecules has been designed, synthesised and characterised. The convergent route to dendrimers and the reactions of the selective coupling agent, carbonyl diimidazole (GDI) were employed. The method was successful in the preparation of first, second and third generation dendrimers and dendrons of the first to fourth generations. The structure of the termini of these branched macromolecules was varied to consist of r-butyl, benzhydryl, cyclohexyl or 4-heptyl groups. The dendrons were also coupled to a trifunctional aromatic core unit to create another series of dendrimers with an innermost layer of ester functions. The compounds prepared were soluble in most common organic solvents and insoluble in water. The physical state of the materials ranged from sticky oils to hard, amorphous solids depending on the nature of the end groups and the molecular weight of the macromolecules. The synthesis of the second generation dendrimer with (-butyl end groups was adapted to make a series of six codendrimers with differing arrangements of concentric layers of urethane and carbonate functions as well as the polycarbonate analogue. These second-generation dendrimers varied in their physical state from oils of low viscosity to hard amorphous solids depending on the proportion of carbonate and urethane functions in the molecule. The hydrogen bonding interactions in solution of some of the dendritic compounds were investigated by (^1)H NMR and infrared spectroscopy. From the analysis it was concluded that the hydrogen bonding was intramolecular rather than intermolecular in nature and that the degree of hydrogen bonding was dependent on the generation and the terminal groups of the structures. In addition, the degree of hydrogen bonding of the urethane functions was observed to be dependent on the location of the urethane layers in the second generation poly(urethane-carbonate) codendrimers. The thermal properties of the dendrimers were investigated and the materials observed to have a single glass transition. The glass transition temperatures of the dendritic families with different termini were found to be dependent on the composition of the end group and the molecular weight of the molecule. The glass transition temperatures of the codendrimers were dependent on the proportion of urethane and carbonate links in the structure and also the relative location of the layers. In a preliminary study, it was shown that blends of two different dendrimers were characterised by only one glass transition.
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Mistry, Jinesh. "Synthesis and conformational analysis of polyarene dendrimers." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/synthesis-and-conformational-analysis-of-polyarene-dendrimers(650b10eb-6afd-471c-b688-5f86ee65f42c).html.
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Polyarene dendrimers with rigid aromatic regions are of interest due to their shape persistent nature. A novel series of G1 dendrimers containing a substituted 1,3-phenyl core are reported and were found to exhibit atropisomerism. This was investigated in the solid state (X ray), in solution (NMR), and via computational studies. The synthesis of fluorinated G1 dendrimers allowed for the analysis of interconversion between conformations via 19F-19F EXSY NMR (exchange spectroscopy). These were shown to exist as two distinct sets of three interconverting atropisomers. Each atropisomer was identified as well as their respective interconversion pathway. By increasing the size of the core of the G1 dendrimers resulted in physical separation of atropisomers by preparative HPLC. Results suggest certain conformers are energetically unfavourable reducing the total number of atropisomers observed.
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Nimmagadda, Alekhya. "Design, Synthesis, Applications of Polymers and Dendrimers." Scholar Commons, 2017. https://scholarcommons.usf.edu/etd/7430.
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WHO has reported that antibiotic resistance is the third major cause of human death all over the globe. Recent study, has focused on the development of new antibacterial resistance drugs. Herein, we tried to synthesis a series of polymers that can mimic the HDPs. HDPs can target the bacterial cell membrane and they have less chances to develop bacterial resistance. We synthesized the amphiphilic polycarbonates that are highly selective to Gram-positive bacteria, including multidrug resistant pathogens. The membrane disruption activity of these polymers was proved by fluorescence and TEM studies and the drug resistance study showed that the polymers don’t develop bacterial resistance. In order to further design the molecules that can target a broad spectrum of bacteria, we have designed a series of lipidated dendrimers that can target the Gram-positive and Gram-negative bacteria. These dendrimers mimic the HDPs and target the bacterial cell membrane. Dendrimers are reported to inhibit the formation of bacterial biofilm which makes them promising for their future development of antibiotic agents.
Apart from the synthesis of polymers and dendrimers as antibacterial agents, we have designed a series of small molecular antibacterial agents that are based on the acylated reduced amide scaffold and small dimeric cyclic guanidine derivatives. These molecules display good potency against a panel of multidrug-resistant Gram-positive and Gram-negative bacterial strains. Meanwhile, they also effectively inhibit the biofilm formation. Mechanistic studies suggest that these compounds kill bacteria by compromising bacterial membranes, a mechanism analogous to that of host-defense peptides (HDPs). Lastly, we also demonstrate that these molecules have excellent in vivo activity against MRSA in a rat model. This class of compounds could lead to an appealing class of antibiotic agents combating drug-resistant bacterial strains.
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Dotson, Michael Edward. "Improvements in Pamam Dendrimer Synthesis." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin998323664.
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Soomro, Shahid A. "Design, synthesis and photochemical studies of stilbenoid dendrimers." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975958569.
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Acosta, Otero Erick J. "Synthesis and application of dendrimers on solid supports." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/1576.
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The synthesis, characterization and application of dendrimers on solid supports are described. Melamine-based dendrimers are incorporated on clay minerals and silica gel. The hybrid materials are characterized using a variety of analytical techniques including thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and mass spectrometry (MS). The first chapter gives an overview of the two main methods, convergent and divergent, for the synthesis of dendrimers. It also describes the synthesis of melamine-based dendrimers and their advantages over conventional dendrimers. Synthetic strategies and applications of dendrimers at surfaces are discussed. The preparation of organoclay materials containing dendritic surfactants is presented in the second chapter. The morphology of these organoclays is studied by X-ray powder diffraction (XPD). A new type of morphology is observed when large dendritic surfactants are incorporated onto the clay. This new morphology is described as frustrated intercalation. The ability of the dendritic organoclay composites to recognize small organic molecules in water is presented in the third chapter. Atrazine, a commonly used herbicide, is used as a model compound. Structure-activity relationship studies were conducted in order to gain some insight on the recognition and sequestration mechanisms. In the fourth chapter, reactive resins are evaluated for the covalent sequestration of monochlorotriazines from organic and aqueous solutions. The sequestration is monitored spectrophotometrically and using liquid chromatography coupled to a mass spectrometer (LC-MS). 1H NMR spectroscopy and MS are used to identify the covalent adducts formed between the monochlorotriazines and the resins. The efficiency of the resin is compared to several types of charcoal using aqueous solutions of atrazine. The final chapter describes the attachment of melamine-based dendrimers onto silica gels. Dendrimers are incorporated to the silica gel surface using two synthetic strategies, the stepwise growth strategy (SGS) and the "attach-to" strategy (ATS). These composites are also evaluated for their ability to remove atrazine from aqueous solutions.
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Hourani, Rami. "Design and synthesis of dendrimers for multipurpose tasks." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86681.
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Monodisperse macromolecules with tailored architecture constitute the key to designing efficient and smart nanomaterials. They offer real potential to achieve this goal, and one of the earlier challenges faced by this novel class of macromolecules has been addressed by the evolutions in their synthetic methodologies. In this thesis, i) inorganic, organometallic, and organic synthetic routes are employed to construct mono- and bi-functional dendrimers; and ii) a detailed study including an evaluation of their structure-property relationships using a combination of experiment with theoretical calculations, and their applications in molecular encapsulations and drug delivery, are reported. Geometric characterization of 3,5-dihydroxybenzyl alcohol (DHBA)-based dendrimers, using aminosilanes as linkers was achieved using molecular mechanics MM+ method and the PM3 semi-empirical molecular orbital theory. Optimization of DHBA-based dendrimer generations 1-5 (DG1-5) suggested that DG1-3 have a relatively open structure with no internal spaces of any particular size or shape, while DG4 and 5 assume a more globular structure with well-defined internal cavities. Encapsulation of disperse red 1 (DR1) into the cavities of these dimethylsilyl linked DHBA-based dendrimers led to a blue shift in the λmax of DR1, and transmission electron microscopy (TEM) showed a rectangular shape of dendritic aggregates containing DR1. Catalytic activity of (COD)RhCl(PPh2(CH2)3OH) encapsulated in dendritic aggregates of generations 1-4, indicated a significant decrease in catalytic conversion of 1-decene to decane in dendrimer generation 4 upon going from a concentration below critical aggregation concentration (cac) to above cac. Subsequently, a simple divergent methodology to synthesize 1,3,5-triethynylbenzene (TEB)-based dendrimers, using amino stannanes as linkers, was developed. A theoretical evaluation of their structure suggested that they evolve into a turbine shape with benzene ringsLes macromolecules monodisperses possédant une architecture modulée constituent la clé au design de nanomatériaux efficaces et intelligents. Elles offrent un réel potentiel pour atteindre ce but, et un des défis précédemment rencontrés par cette nouvelle classe de macromolécules a été adressé par l'évolution de leurs méthodologies synthétiques. Dans cette thèse, i) des routes synthétiques inorganiques, organométalliques et organiques sont employées pour construire des dendrimères mono et bi-fonctionnels; et ii) une étude détaillée incluant une évaluation de leurs relations structure-propriété, utilisant une combinaison d'expériences incluant des calculs théoriques, ainsi que leurs applications en encapsulation moléculaire et en libération de médicaments, sont rapportées. La caractérisation géométrique de dendrimères composés d'unités d'alcool 3,5-dihydroxybenzyle (DHBA), pontées par des aminosilanes a été accomplie utilisant la méthode de mécanique moléculaire MM+ ainsi que la théorie des orbitales moléculaires semi-empirique PM3. L'optimisation des dendrimères DHBA de génération 1-5 (DG1-5) a suggéré que DG1-3 possèdent une structure relativement ouverte sans espaces internes de grandeur ou de forme particulière, tandis que DG4 et 5 possèdent une structure plus globulaire caractérisée par des cavités internes bien définies. L'encapsulation de disperse red 1 (DR1) dans les cavités des dendrimères composés d'unités DHBA pontés par des diméthylsilyles a mené à un déplacement vers le bleu du λmax de DR1, et la microscopie électronique en transmission (TEM) a démontré une forme rectangulaire pour les agrégats dendritiques comprenant DR1. L'activité catalytique de (COD)RhCl(PPh2(CH2)3OH encapsulé dans les agrégats dendritiques des generations 1-4, a indiqué une diminution significative dans la conversion catalytique de 1-decene à décane pour le dendrimère de génération 4. Subséquemment,
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Zhou, Mingjun. "Elastin-Like Peptide Dendrimers: Design, Synthesis, and Applications." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/101661.
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Elastin like peptides (ELPs)—derived from the protein elastin—are widely used as thermoresponsive components in biomaterials due to their LCST (lower critical solution temperature) behavior at a characteristic transition temperature (Tt). While linear ELPs have been well investigated, few reports focused on branched ELPs. Using lysine (Lys, with an additional side-chain amine) as branching units, ELP dendrimers were synthesized by solid-phase peptide synthesis (SPPS) with up to 155 amino acid residues. A secondary structure change with decreasing ratio of random coil and increasing ratio of β-turn upon heating, which is typical of linear ELPs, was confirmed by circular dichroism spectroscopy for all peptides. Conformational change did not show evident dependence on topology, while a higher Tt was observed for dendritic peptides than for their linear control peptides with the same number of GLPGL repeats. Variable-temperature small-angle X-ray scattering (SAXS) measurements showed a size increase and fractal dimension upon heating, even below the Tt. These results were further confirmed by cryogenic transmission electron microscopy (cryo-TEM), and micro differential scanning calorimetry (micro-DSC), revealing the presence of aggregates below the Tt. These results indicated the presence of a pre-coacervation step in the LCST phase transition of the ELP dendrimers.
We further prepared hydrogels by crosslinking hyaluronic acid (HA) with ELP dendrimers. We invesigated their physical properties with scanning electron microscopy (SEM), swelling tests, SAXS, and model drug loading/release experiments. Most of the HA_denELP hydrogels retained transparent upon gelation, but after lyophilization and reswelling remained opaque for days. This reswelling process was carefully investigated with time-course SAXS studies, and was attributed to forming pre-coacervates in the gelation step, which slowly reswelled during rehydration. We then prepared hydrogels with H2S-releasing aroylthiooxime (SATO) groups and showed human neutrophil elastase-responsive H2S-releasing properties with potential applications in treating chronic diseases with recurring inflammation.
Furthermore, we prepared a series of wedge-shaped triblock polyethylene glycol (PEG)-ELP dendrimer-C16 (palmitic acid) conjugate amphiphiles with adjustable Tts. Various techniques were used to investigate their hierarchical structures. The triblock PEG-peptide-C16 conjugate amphiphiles were thermoresponsive and showed a morphology change from small micelles to large aggregates. However, the hydrophilic shell and strong tendency for micelle formation limited the thermoresponsive assembly, leading to slow turbidity change in the LCST transition. The secondary structure was twisted from conventional β-sheet, and the thermoresponsive trend observed in typical ELP systems was not observed, either. Variable temperature NMR showed evidence for coherent dehydration of the PEG and ELP segments, probably due to the relatively short blocks. Utilizing the micelles with hydrophobic cavity, we were able to encapsulate hydrophobic drugs, with promising applications for localized drug release in hyperthermia.Doctor of Philosophy
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Gobouri, Adil Abdullah H. "Synthesis and characterization of novel BINOL-based symmetrical and asymmetrical axially chiral dendrimers." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/synthesis-and-characterization-of-novel-binolbased-symmetrical-and-asymmetrical-axially-chiral-dendrimers(27e9cb60-7ef9-4178-9ed1-44fcfd216a65).html.
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Synthesis of optically active dendrimers based on 1,1'-bi-2-naphthol enantiomers and their derivatives as core units is growing rapidly due to the unique behavior and properties of the new compounds and their various valuable applications in several fields such as asymmetric catalysts, enantioselective fluorescent sensors and in chiral molecular recognition. To the best of our knowledge, the synthesis of binaphthyl-based symmetrical and asymmetrical axially chiral dendrimers via 1,3-cycloaddition reactions ["Click" chemistry] using Fréchet-type dendrons and their azido-analogues has not been studied yet. The principal aim of this project was the synthesis and characterization of a novel series of binaphthyl-based symmetrical and asymmetrical axially chiral dendrimers via "Click" and etherification reactions, and then determination of the specific and molar rotation of the new dendrimers to investigate the influence of linkage nature between the dendritic wedges and the core units on the optical properties in presence of the triazole ring by comparing of the properties of the new dendrimers with the dendrimers reported in literature, in addition to study the influences of different chemical groups near the dendritic wedges on the optical properties of the novel synthesized dendrimers. In conclusion, several families of novel BINOL-based symmetrical and asymmetrical axially chiral dendrimers have been synthesized by the reaction of well-known BINOL derivatives as core units with Fréchet-type dendrons and their azido-analogues via "Click" and etherfication reactions for the first time. All new dendrimers were obtained in very good yields which confirm the effectiveness of "Click" reaction in this type of synthesis. The new dendrimers were fully characterized by 1H, 13C and HMQC NMR spectroscopy, mass spectrometry, IR spectroscopy and UV-Vis spectrometry. All new dendrimers show moderate optical activity. Changes in the specific and molar rotation are characterized by a general decrease in the specific rotation and a general increase in the molar rotation with the increase in the dendritic wedges generation in each series of the synthesized dendrimers. By our current knowledge, the increase in the specific rotation as generation increases of (S)-358, (S)-359 and (S)-360 observed in this research is the first such observation. The presence of the triazole ring in the linkage between the core unit and the dendritic wedges plays an important role in reducing of the steric repulsion between the two naphthyl units and in reducing of the effect of the dendritic wedges generation on the torsional angle by making the wedges far away from the attachment point of the two naphthyl units.
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Nilsson, Camilla. "Dendrimers : Synthesis, Characterization and Use in Thiol-Ene Networks." Doctoral thesis, KTH, Fiber- och polymerteknik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9763.
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Dendrimers are perfectly branched, well-defined macromolecules with a layered structure and a large amount of peripheral end groups. The high functionality in combination with the possibility of dendrimers to adopt a globular shape at high molecular weights, gives them very unique properties.In this work dendrimers up to fifth generation based on 2,2-bis(methylol)propionic acid (bis-MPA) were synthesized with different core structures. The core moieties were chosen in aspects of functionality and flexibility and the impact of the core on the physical and rheological properties was studied. By using the divergent growth approach dendrimers with acetonide, hydroxyl, allyl ether and methacrylate end groups were obtained.The bulk properties of the acetonide- and hydroxyl- terminated dendrimers were investigated with a rheometer. Temperature sweep tests were performed on the acetonide protected dendrimers in a temperature range of -50 up to 120°C at a constant frequency of 1 Hz. It was observed that the glass transition temperature (Tg) increased with increasing generation and that the modulus dropped without a trace of rubbery plateau for lower generations. This lack of rubbery plateau is due to the absence of entanglements between dendrimers. Interestingly, a small rubbery plateau was visible for generation five which implies enhanced interactions between the dendrimers. This behaviour suggests to be strongly influenced by the structural collapse at higher generations. Further, frequency sweep tests were performed on hydroxyl functional dendrimers at different temperatures. The results revealed Newtonian properties for lower generations and shear-thinning behaviour for higher generations at high frequency.Furthermore, this research involves the creation of well-defined thiol-ene networks by incorporation of allyl ether or methacrylate functional dendrimers in thermosets. This was accomplished by using two trithiols of different molecular weights and react them with the enes under UV irradiation. The thiol-methacrylate crosslinking reaction resulted in inhomogeneous films with and residual unsaturations. The thiol-ene films based on allyl ether dendrimers, on the contrary, resulted in homogeneous films with intermolecular couplings between the ene and the thiol being the dominant mode of polymerization.Dendrimerer är perfekt grenade, väldefinierade molekyler med en struktur indelad i lager och med ett stort antal ändgrupper. Dendrimerer har, på grund av sina många funktionella grupper och sin förmåga att vid höga molekylvikter anta en mer sfärisk struktur, väldigt speciella egenskaper. Dendrimerer upp till femte generation, baserade på 2,2-dimetylolpropan syra (bis-MPA), har syntetiserats med olika typer av kärnstrukturer. Kärnorna valdes med avseende på funktionalitet och flexibilitet, och strukturens påverkan på dendrimerernas fysikaliska och reologiska egenskaper undersöktes. Dendrimerer med acetonid-, hydroxyl-, allyleter- samt metakrylatändgrupper syntetiserades genom att använda en divergent syntesmetod. De hydroxyl- och acetonidfunktionella dendrimerernas reologiska egenskaper i bulk karakteriserades med en reometer. De acetonidskyddade dendrimererna karakteriserades med temperatursvep i ett intervall mellan -50 °C och 120°C och med en konstant frekvens på 1 Hz. Analyserna visade att glastransitionstemperaturen (Tg) ökade med ökande generation och att dendrimerer av lägre generation inte uppvisade någon gummiplatå. Anledningen till detta är att det inte förekommer några kedjeintrasslingar mellan dendrimerer. Dock uppvisar femte generationens dendrimerer liten gummiplatå vilket pekar på ökade interaktioner mellan dem. Detta beteende påverkas av att dendrimerna kollapsar vid höga generationer och att förändringen i strukturen tydligt påverkar interaktionerna. Hydroxylfunktionella dendrimererna karaktäriserades med frekvessvep vid olika temperaturer. Det visade sig att lägre generationer uppvisar Newtonskt beteende medan högre generationer visar sig vara skjuvförtunnande vid höga frekvenser. Som en ytterligare del i detta projekt skapades väldefinierade tiol-en nätverk genom att reagera allyleter och metakrylat-funktionella dendrimerer med två trifunktionella tioler av olika molekylvikt. Reaktionerna initierades med UV-ljus. Tiol-metakrylat filmerna visade på en hög andel homopolymerisation vilket resulterade i inhomogent tvärbundna nätverk med ett stort antal oreagerade grupper. Tiol-allyleter filmerna visade uppvisade däremot homogena nätverk med en liten andel homopolymerisation.
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Hooper, Richard. "Synthesis, characterization and group modification of carbosilane based dendrimers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ34267.pdf.
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Dembowa, Aneta. "Synthesis and Characterization of Amphiphilic Iron-Sulfur Core Dendrimers." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-01022005-192535/.
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Synthesis of water soluble carboxylate-terminated Fe4S4-core was carried out. Convergent method was chosen to build three generations of dendrons. Several synthetic schemes were explored. The syntheses were conducted with 4,4-bis(hydroxyphenyl)penthanol as a repeat unit and N,N-dimethyl thiocarbamate and methyl ester or methoxy-methyl as protecting groups. The conditions for deprotection and ligand exchange have been proposed. 1H, 13C and MALDI-MS were used to characterize synthesized molecules.
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Rendell, Jacob Thomas. "Synthesis and Study of Chiral Dendrimers and Pincer Ligands." Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498982.
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Thatti, Ravtej Singh. "The synthesis and properties of phenyl-cored thiophene dendrimers." Thesis, Kingston University, 2016. http://eprints.kingston.ac.uk/37349/.
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Dendrimers are globular macromolecules that have a range of applications. These nonnally exploit the individual prope1ties of the functional groups that make up the overall dendrimer. The polyvalent properties of dendrimers are widely used in biomedical scaffolds and catalysis. The internal cavities with the structure can also be harnessed for encapsulation. This application has evoked interest especially within the bio-medical field, using dendrimers as host molecules to increase the solubility of drug molecules. In this research, a set of dendrimers were prepared to test the potential of encapsulation and manipulation of the host structure. The dendrimer products contained thiophene spacer groups and a thiophene outer shell, with alkylated terminal groups. The hetcro aromatic rings were held around a phenyl core and internal generations to create the cavity space. After the phenyl-cored thiophene dendrimers were fully characterised, iodoform was used as a guest molecule and incorporated into the dendrimer structure to fonn an encapsulation complex. At this point it was seen that the second dendrimer had the potential to encapsulate and hold iodoform within its internal structure. UV-visible spectroscopy was used to verify how the presence and the overall amount of encapsulated iodofonn. Following these results a microgravimetric study was carried out, and it confinned the ratio of dendrimer to iodof01m (I :2.76). A minimised (MM3) molecular model of each of the dendrimers indicated that there was a possible van der Waals interaction between the thiophene moieties of the dendrimer and iodoform and confirmed that the second dendrimer was more likely to be efficient in encapsulating the guest molecule. Fmther molecular modelling showed that a four branched dendron was likely to increase the encapsulation potential. The dendrimers were exposed to iodine vapour to study the effect of doping. This was followed by UV-visible spectrometry, but data were mainly collected and compared by electrical conductivity measurements. It was shown that the dendrimer which contained a larger number of conjugated thiophene rings was much more conductive. The calculated charge carrier mobilities and conductivities were relatively low compared to those of large thiophene oligomers or polythiophene. This was expected as the charge had to hop frequently between dendrimer molecules compared to a single polymer. It was predicted that after encapsulation, the oxidised dendrimer complex would be affected by some torsion of the bond between the thiophene rings. Cyclic voltammetry for the second dendrimer displayed peaks for both n- and p-type doping. From this, the electrochemical band gap was calculated and compared to the optical band gap obtained from the UV-visible spectrum. The values were 2.6 ±0.1 eV.
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Sahota, Hardeep. "Synthesis and applications of polyester dendrimers and hyperbranched polymers." Thesis, University of Warwick, 1996. http://wrap.warwick.ac.uk/106909/.
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Dendrimers are an important new class of macromolecule which have many potential applications from drug delivery to metal extraction. A number of methods have been developed for the synthesis of dendrimers and related hyperbranched polymers. We chose the divergent initiator core method to synthesise three series of dendrimers with phloroglucinol, hydroquinone and naphthalene-2,6-diol as the core moieties, using DCC in the presence of DPTS as the esterification agent. The fluorescence of the naphthalene core was used to investigate the microenvironment of the core. Early investigations indicate there is a marked change in the core’s environment between generations two and four. MALD1-MS was tested as a method for the analysis of dendrimers and hyperbranched polymers. Molecular masses of dendrimers were obtained within 2 Da in every case, although low mass ions are sometimes observed. The origin of the low mass species is not yet entirely clear although there are indications that these arise from both the MALDI-MS process and during synthesis. 'lhe synthesis of poly(3,5-dihydroxybenzoic acid), again using the DCC- DPTS esterification agent was investigated. This method was found to give hyperbranched polymers which were difficult to handle. Studies by MALDI-MS indicate the difficult handling properties are a result of DCC being bound to the hyperbranched polymer. Thus, a modification of Fréchet’s method was used to prepare poly(3,5-dihydroxybenzoic acid). It was demonstrated that the hydroxyl terminated dendrimers and hyperbranched polymers could be functionalized at the branch termini with units such as acetyl, pent-4-enoyl, oleoyl and lineoyl. Epoxy terminated dendrimers and hyperbranched polymers were also prepared. The epoxy terminated dendrimers were analysed as potential crosslinking agents for polyester powder coatings. Initial results indicate that the epoxy groups prefer to react with one another rather than with the resin and thus little curing of the resin was observed.
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Alminderej, Fahad Mohammad. "SYNTHESIS AND CHARACTERIZATION OF POLYURETHANE DENDRIMERS SUBSEQUENT CLICK REACTION." Miami University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami1469447068.
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Berezhnaia, Veronika. "Synthesis and characterization of helicenes, dendrimers and molecular asterisks." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0341.
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Projet de thèse consiste de plusieurs parties:-synthèse de nanographène chirale, caractérisation de ses propriétés photo-physiques (publication en JACS acceptée);-synthèse des astérisques moléculaires, qui combinent les propriétés luminescences du noyau benzène persulfuré et des solubilité aqueuse et biocompatibilité des dendrons avec des branches de PEG; une application de ces dendrons pour couvrir les nanoparticules de silice ;-synthèse des astérisques moléculaires avec noyau de benzène persulfuré et branches des heterocycles, pour explorer leurs auto-assemblage et propriétés chelatantes vers métauxThe synthesis of molecular asterisks as "smart sensors" with a persulfurated benzene core and various ligands was explored. Asterisks with heteroaromatic ligands were synthesized for exploring their metal ions complexing ability. PEG dendrons were tested for increasing the water solubility of the asterisks, and to verify if PEG asterisks could encapsulate some hydrophobic molecules. The PEG dendrons were synthesized for making smart asterisks sensors, and for another purpose: the coating of silica nanoparticles to prevent their fast degradation in water. Unfortunately, this protection from degradation was ineffective, but we could make PEG asterisks to encapsulate molecules (Nile Red) toward new drug nanocarriers.The synthesis of chiral nanographenes embedding [5]- or [7]helicenes is reported. Usually [5]helicenes are configurationally labile, while higher helicene homologs are stable. We synthesized a stable chiral nanographene with six embedded [5]helicene units (a [5]helicene trimer). We found a strong distortion of benzene rings, especially in the triphenylene core. The enantiomers were separated and the chiroptical properties were measured.The synthesis of [7]helicene trimer was also performed with a great enantio- and diastereoselectivity. When a Ni(0)- mediated cyclotrimerization is achieved with an enantiopure [7]helicene substrate, only one enantiomer of the trimer is obtained, while keeping intact the configuration of the substrate. On a racemic substrate, three diastereomers were obtained. One of them demonstrated the highest values of a benzene ring distortion reported to date (mean puckering angle and twisting angle)
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Berezhnaia, Veronika. "Synthesis and characterization of helicenes, dendrimers and molecular asterisks." Electronic Thesis or Diss., Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0341.
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Projet de thèse consiste de plusieurs parties:-synthèse de nanographène chirale, caractérisation de ses propriétés photo-physiques (publication en JACS acceptée);-synthèse des astérisques moléculaires, qui combinent les propriétés luminescences du noyau benzène persulfuré et des solubilité aqueuse et biocompatibilité des dendrons avec des branches de PEG; une application de ces dendrons pour couvrir les nanoparticules de silice ;-synthèse des astérisques moléculaires avec noyau de benzène persulfuré et branches des heterocycles, pour explorer leurs auto-assemblage et propriétés chelatantes vers métauxThe synthesis of molecular asterisks as "smart sensors" with a persulfurated benzene core and various ligands was explored. Asterisks with heteroaromatic ligands were synthesized for exploring their metal ions complexing ability. PEG dendrons were tested for increasing the water solubility of the asterisks, and to verify if PEG asterisks could encapsulate some hydrophobic molecules. The PEG dendrons were synthesized for making smart asterisks sensors, and for another purpose: the coating of silica nanoparticles to prevent their fast degradation in water. Unfortunately, this protection from degradation was ineffective, but we could make PEG asterisks to encapsulate molecules (Nile Red) toward new drug nanocarriers.The synthesis of chiral nanographenes embedding [5]- or [7]helicenes is reported. Usually [5]helicenes are configurationally labile, while higher helicene homologs are stable. We synthesized a stable chiral nanographene with six embedded [5]helicene units (a [5]helicene trimer). We found a strong distortion of benzene rings, especially in the triphenylene core. The enantiomers were separated and the chiroptical properties were measured.The synthesis of [7]helicene trimer was also performed with a great enantio- and diastereoselectivity. When a Ni(0)- mediated cyclotrimerization is achieved with an enantiopure [7]helicene substrate, only one enantiomer of the trimer is obtained, while keeping intact the configuration of the substrate. On a racemic substrate, three diastereomers were obtained. One of them demonstrated the highest values of a benzene ring distortion reported to date (mean puckering angle and twisting angle)
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Sims, Michael Keith. "Design and synthesis of dendrimers for studying two-photon absorption characteristics." Thesis, Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/sims/SimsM0507.pdf.
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Thomas, Stephen Patrick. "Phosphorus mediated asymmetric cyclopropane synthesis." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613118.
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Nissen, Shannon Rae. "The synthesis of disaccharides for the functionalization of pamam dendrimers." Thesis, Montana State University, 2011. http://etd.lib.montana.edu/etd/2011/nissen/NissenS1211.pdf.
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An increase in the number of incidences of fungal disease among immuno-compromised patients has developed in recent years. While a patient with an intact immune system would be able to fight the pathogen, an immunocompromised patient is not able to do so. The mortality rate of disseminated candidiasis can be as high as 30-40%. Although there have been great advances in the understanding of how the immune system detects pathogens, there is still much to be learned. PAMAM (poly(amidoamine)) dendrimers have been chosen as scaffolds on which to display disaccharides that are found on the surface of Candida albicans. Preliminary results from immunostimulation assays using a(1,2)-dimannose functionalized PAMAM dendrimers showed that disaccharide functionalized dendrimers can stimulate cytokine production. In light of these results, several disaccharides - phenyl 2-O-benzyl-4,6-O-benzylidene-3-O-(2,3,4,6-tetra-O-acetyl-a-D-mannopyranosyl)-1-thio-a-D-mannopyranoside, 1-O-2-(2-azidoethoxy)ethyl-3-O-benzyl-4,6-O-benzylidene-2-O-(2,3-di-O-benzyl-4,6-O-benzylidene-B-D-mannopyranosyl)-a-D-mannopyranoside, 1-O-2-(2-azidoethoxy)ethyl-3-O-benzyl-4,6-O-benzylidene-2-O-(2,3-di-O-benzyl-4,6-O-benzylidene-B-D-glucopyranosyl)-B-D-glucopyranoside, 1-O-2-(2-azidoethoxy)ethyl-2-O-benzyl-4,6-O-benzylidene-3-O-(2,3-di-O-benzyl-4,6-O-benzylidene-B-D-glucopyranosyl)-B-D-glucopyranoside - have been synthesized for the functionalization of G(3.5) PAMAM dendrimers.
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Jenkins, Alan Charles. "Synthesis and functionalisation of PAMAM dendrimers as histone replacement molecules." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/173861/.
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The primary objective of this work was to synthesise and structurally modify a series of PAMAM dendrimers with a view to investigating and controlling their complexation with, and compaction of, DNA. The Introduction gives an overview to the origins of polymer and dendrimer science, and describes the synthetic approaches and resulting properties of dendrimers together with their impact on biological systems. The preparation of poly(amidoamine) (PAMAM) dendrimers utilising a number of different core materials are reported and characterised in Chapter 2. The conformational motion of the dendritic branches has been studied using 1H spin-lattice relaxation time experiments, and the results have been compared for the differently cored materials. Chapter 3 examines the modification of the dendrimer surfaces with acetyl, poly(ethylene glycol) and fluorescent groups and reports the results of a study of how the degree of DNA condensation affects gene expression by analysing dendrimer-DNA compaction using linear dichroism, dynamic light scattering and competitive binding of ethidium. Experiments designed to investigate modified dendrimer-lipid interactions are also discussed and the results of these are compared to molecular dynamic simulations. The synthesis of novel small molecules based around L-histidine and photo-responsive azobenzene, and the use of these to modify the surface of 4th and 5th generation PAMAM dendrimers is reported in Chapters 4 and 5 respectively. There follows a final chapter containing detailed descriptions of the synthetic procedures and characterisation for each of the compounds studied and the experimental methods used for exploring their behaviour
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Hearshaw, Meredith Ann. "The synthesis, structure and chemistry of some novel organometallic dendrimers." Doctoral thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/9756.
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Includes bibliographical references.The synthesis and chemistry of several series of novel organometallic dendritic wedges and small dendrimers containing iron, ruthenium, cobalt and tungsten have been investigated. The compounds have been synthesised using the convergent methodology of Hawker and Fréchet. Haloalkyl complexes such as Cp*Fe(CO)₂(CH₂)₃Br and CpRu(CO)₂(CH₂)₃Br were used for the synthesis of the dendrimers. In this approach, the metal and ligand system remain on the periphery of the dendrimer. The synthesis proceeds via successive coupling and activation steps. Many of the dendritic wedges decomposed during the activation procedure. All the dendritic wedges and first generation dendrimers were soluble in common organic solvents and were characterised by IR, ¹H and ¹³C NMR spectroscopy, mass spectrometry and microanalysis where possible. The organoruthenium dendrimers are significantly more stable at room temperature and in solution than all the iron analogues. The steric hindrance imparted by the cobaloxime ligand allowed only the zero-generation dendrimer to be synthesised. Several heterobimetallic dendritic wedges were synthesised as well as a hybrid block copolymer. The surface functionalisation of bromobenzyl-terminated dendrimers was attempted. The data are discussed and some properties and reactions of the compounds are described. The x-ray crystal structures of a dendritic precursor, [CpFe(CO)₂(CH₂)₃Br] (space group P2₁/c) and first generation ruthenium dendritic wedge (space group Cc) have been determined at low temperature. Calculated molecular structures were generated with the HYPERCHEM(TM) program; the dendritic wedges are fairly open structures while the first generation dendrimer adopts a more spherical shape. Cyclic voltammetry studies were carried out on several of the iron and ruthenium dendrimers. The cyclic voltammograms of all the complexes showed a single irreversible oxidation peak; this suggests that there is no interaction or communication between the metals. The thermal behaviour of some of the organoiron dendrimers was also investigated by thermogravimetric analysis and differential scanning calorimetry. The latter traces generally showed one endothermic peak which could be assigned to melting. The chemical reactivity of a first generation ruthenium dendrimer was investigated; this dendrimer was found to react more slowly than the mononuclear complexes. This first generation dendrimer, supported on silica, was tested as a catalyst in the Fischer-Tropsch synthesis. This mono-atomic ruthenium dendrimer was found not to have sufficient catalytic activity for this purpose. The chemical and physical properties of these dendrimers are discussed.
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Steffensen, Mackay Bagley. "Methods for the syntheses of compositionally diverse dendrimers." Texas A&M University, 2004. http://hdl.handle.net/1969.1/2724.
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Dendrimers are a unique class of macromolecules that present perfect branching on a molecular scale. The pattern of branching at the atomic scale is compared to the branching of trees, from whence dendrimers get their name. Dendrimers have been attractive synthetic targets for the past twenty years. The methods and building blocks used in the synthesis of dendrimers vary, but molecules of this class of polymeric materials all possess symmetrical branching emanating from the core. At each branch point the number of groups increases exponentially. Efforts directed toward the synthesis of dendrimers presenting multiple functional groups at the surface and within the dendrimer structure are described.
Methods are described which provide access to dendrimers in a one-pot per generation fashion, with triazines as the common moiety. Chemoselective routes utilize the temperature dependant substitution of cyanuric chloride to construct dendrimers, obviating the use of protected monomers or the need to manipulate functional groups during the synthesis. These methods are atom economical, as the only by-products are HCl and a base to scavenge it. The methods are efficient, with typical isolated yields of product in the middle to high ninety percent range, often on a multi-gram scale. Methods are described for conducting three separate reactions in a single pot. Specific emphasis is placed on structural control of the interior and surface groups of the dendrimers.
The synthesis of a G3 dendrimer of layered composition is described. The use of a different difunctional linkage group for each generation of dendrimer growth produced a G3 dendrimer with layered composition without the use of protecting groups or functional group interconversions.
A G3 dendrimer was synthesized presenting five different functionalities at the periphery on a 10 gram scale, resulting in approximately 70% overall yield. The peripheral groups are composed of orthogonal functionality, which can be independently and selectively unmasked or manipulated in the presence of the other functionality.
The syntheses of dendrimers incorporating the short linker hydrazine produce materials with interesting physical properties as well as a low ratio of carbon to nitrogen. The use of dendrimers in the construction of novel macromolecular constructs is also described.
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Kotta, Kishore Kumar. "Design, Synthesis, and Characterization of [1 → 3]; [1 → (2 + 1 Me)]; [1 → (2 + 1)] C-Branched Dendrons and Dendritic Architectures." Akron, OH : University of Akron, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1137081672.
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Thesis (Ph. D.)--University of Akron, Dept. of Chemistry, 2006."May, 2006." Title from electronic dissertation title page (viewed 09/17/2006). Advisor, George R. Newkome; Committee members, Michael J. Taschner, David A. Modarelli, Chrys Wesdemiotis, Robert R. Mallik; Department Chair, Michael J. Taschner; Dean of the College, Ronald F. Levant; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
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Crampton, Hannah Louise. "Synthesis and characterization of melamine-based dendrimers with potential biological applications." Thesis, [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2673.
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KIM, NAMJIN. "Synthesis and Characterization of Amphiphilic Fe4S4-Core Dendrimers as Protein Models." NCSU, 2006. http://www.lib.ncsu.edu/theses/available/etd-07052006-133137/.
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The ultimate goal of this research is to clarify the structural effects on the rate and driving force for electron transfer in amphiphilic iron-sulfur core dendrimers, which can eventually be used as protein models. These dendrimers were synthesized by ligand exchange reactions, including the synthesis of dendrons via a modular synthesis approach. Their structure-property relationships were then investigated using electrochemical methods. Three different routes were used to synthesize thiol dendrons with both cationic and anionic peripheral units. The first utilized the disulfide linkage as a focal and protecting group. However, due to difficulties associated with generating free thiol from the disulfide, only partially-substituted dendrimers were prepared in ligand exchange reaction. Similar problems were encountered with the next two methods, which used thiocarbamate and trityl protecting groups, respectively. First generation dendrimers were successfully prepared and characterized using the thiocarbamate group; however, low thiol concentration resulted in only partially substituted dendrimers for the second generation. All synthetic attempts using the trityl focal group resulted in only partial substitution. Because the concentration of free thiol was the factor limiting the synthesis of these amphiphilic iron-sulfur core dendrimers, a protocol was established to measure the thiol concentration using Ellman?s reagent test. However, this proved to be inaccurate due to oxygen dissolved in solution and then re-oxidized thiols during the course of the test. The electrochemical properties of these cationic and anionic dendrimers were measured and compared to G1-flexible dendrimer previously studied by the Gorman Group. G1-cationic dendrimer exhibited more effective attenuation of the electron transfer rate than G1-flexible dendrimer. This was attributed to the difference of molecular weight in both dendrimers. The redox potential in the cationic dendrimer was shifted more positively by about 100 mV due to polar microenvironment around the iron-sulfur core. Cyclic voltammogram of G1-anionic dendrimer exhibited an unexpected peak so other electrochemical properties could not be measured. Only an approximate redox potential was obtained and exhibited a positive shift by about 60 mV compared to G1-flexible dendrimer.
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Alsehli, Mosa Halal. "Synthesis and photophysical properties of novel porphyrin dendrimers containing organoiron complexes." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/36938.
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Dendritic porphyrins and metalloporphyrins are of great interest for their applications
in many fields such as light-energy conversion, photodynamic therapy (PDT), third-order nonlinear
optical materials, organic light-emitting diode (OLED) devices, fluorescence switches,
and molecular wires. The synthesis and preliminary photophysical properties of novel
porphyrin and metalloporphyrin dendrimers containing cationic η⁶-chloroarene-η⁵-
cyclopentadienyliron(II) complexes functionalized with naphthalene and capped with
ferrocene are described. The incorporation of cationic η⁶-chloroarene-η⁵-cyclopentadienyliron
moieties can enhance solubility and facilitate nucleophilic aromatic substitution and addition
reactions due to the intense electron-withdrawing ability of the iron center.
Divergent approaches were employed to give highly symmetrical branched materials.
The preparation of these dendrimers was achieved via metal-mediated nucleophilic aromatic
substitutions and Steglich esterifications. These dendrimers and their precursors were
characterized through nuclear magnetic resonance spectroscopy, infrared spectroscopy, and
ultraviolet-visible and fluorescence spectroscopy.
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Vassilieff, Tatiana. "Dumbbell shaped dendrimers: synthesis, characterization and application in assemblilng silver nanoparticles." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19290.
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Synthesis and detailed characterization of dendrimers that evolve symmetrically from a linear bifunctional core (2-butyne-1,4-diol) with 3,5-dihydroxybenzyl alcohol based dendron wedges, are reported. The divergent, layer-by-layer build-up of the dumbbell shaped dendrimers, is based on simple acid-base hydrolytic chemistry of bis(dimethylamino)dimethylsilane with OH terminated molecules. Evaluation of some of the structure-property relationships in these dendrimers was carried out to obtain a better understanding of their potential applications. The self-assembly of these dendrimers in THF and water is significantly influenced by their generation number, the backbone structure and the solvent. Generations 1-3 dendrimers form aggregates at a higher critical aggregation concentration (cac) compared to generation 4 in THF. This behavior is related to the open structure in the lower generations with a linear core becoming important in their self-assembly, while in generation 4, more globular architecture with more prominent hydrogen bonding sites, facilitates self-assembly at lower concentrations. In water and in generations 1 and 2 dendrimers, the inability of more polar solvent to interact with their backbones, leads to aggregates that are formed by minimizing the repulsive forces. In generations 3 and 4, the major interaction of the solvent with the dendrimer is at the periphery which has a higher concentration of polar OH groups, and it does not interfere significantly with their ability to self-associate. Using these dendrimers as templates, a simple methodology in which silver nanoparticles are synthesized in one pot reaction, has been developed. The dendrimer structure provides reactive peripheral hydroxyl groups as wellCe master présente la synthèse et la caractérisation détaillée de dendrimères symétriques constitués d'un noyau bifonctionnel linéaire (2-butyne-1,4-diol) et de dendrons formés à partir de l'alcool 3,5-dihydroxybenzylique. La construction divergente, couche-par-couche de ces dendrimères en forme d'haltères est basée sur une simple hydrolyse acido-basique entre l'aminosilane Me2Si(NMe2)2 et les molecules possédant des groupements hydroxyles terminaux. Certaines propriétés physiques de ces dendrimères ont été explorées afin de mieux comprendre leurs applications potentielles. Notamment, nous avons démontré que l'auto- assemblage de ces dendrimères en agrégats dépend du nombre de génération, de leur structure et du solvant. En effet, les dendrimères de générations 1 à 3 forment des agrégats à une concentration critique d'agrégation plus élevée que celle des dendrimères de génération 4 dans le THF. Ce phénomène est dû à la structure plutôt ouverte des dendrimères de basse génération qui possèdent un noyau linéaire devenant prédominant dans le phénomène d'auto-assemblage. Par contre, les dendrimères de génération 4 adoptent une architecture plus globulaire qui favorisent les liaisons hydrogène et facilitent leur auto assemblage à basses concentrations. Dans l'eau, les dendrimères générations 1 et 2 forment des agrégats en minimisant leurs forces répulsives, ce solvant plus polaire ne pouvant que très peu interagir avec les noyaux aromatiques constituant les dendrons. Dans le cas des dendrimères de générations 3 et 4, le solvant interagit principalement avec les groupes hydroxyles terminaux présents à plus haute concentration, et ceci n'influence pas de manière sig
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Morley, Timothy Andrew. "A novel approach for the synthesis of dendrimers with defined surfaces." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406044.
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Wang, Qi. "Synthesis of multi-functional dendrimers for targeted delivery of nucleic acids." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4068/document.
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Nous avons démontré que structurellement flexibles poly(amidoamine) (PAMAM) dendrimères sont efficaces système de livraison de siRNA in vitro et in vivo récemment. Nous voulons mener une enquête plus approfondie sur la livraison de siRNA ciblés en utilisant des dendrimères conjugués avec des ligands spécifiques ou d'anticorps, qui peuvent reconnaître les récepteurs correspondants ou des protéines exprimées à la surface des cellules. De cette façon, le siRNA peuvent être livrés spécifiquement aux cellules d'intérêt, conduisant à une délivrance ciblée, ce qui peut améliorer l'efficacité livraison et de réduire la toxicité en évitant les interactions non spécifiques et à des doses plus faibles. À cette fin, nous avons développé des dendrimères portant une chaîne PEG long et un dendron individu polyvalent. La chaîne PEG est de libérer l'encombrement stérique entre dendrimère et ligand / anticorps, tandis que le dendron multivalent fournit une plate-forme d'une conjugaison contrôlable de ligands. Par ailleurs, nous avons également conçu et synthétisé une autre dendrimères PEGylées portant un groupe thiol libre pour la préparation des anticorps / dendrimère conjuguésWe have demonstrated that structurally flexible poly(amido)amine (PAMAM) dendrimers are efficient siRNA delivery system in vitro and in vivo recently. We would like to undertake further investigation on targeted siRNA delivery using dendrimers conjugated with specific ligands or antibodies, which can recognize the corresponding receptors or proteins expressed on the cell surface. In this way, siRNA can be delivered specifically to the cells of interest, leading to targeted delivery, which can further improve the delivery efficiency and reduce the toxicity by avoiding non-specific interactions and at lower doses. To this end, we have developed dendrimers bearing a long PEG chain and an individual multivalent dendron. The PEG chain is to release the steric congestion between dendrimer and ligand/antibody, whereas the multivalent dendron provides a platform of a controllable conjugation for ligands. Besides, we also designed and synthesized another PEGylated dendrimers bearing a free thiol group for the preparation of antibody/dendrimer conjugates
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Wang, Qi. "Synthesis of multi-functional dendrimers for targeted delivery of nucleic acids." Electronic Thesis or Diss., Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4068.
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Nous avons démontré que structurellement flexibles poly(amidoamine) (PAMAM) dendrimères sont efficaces système de livraison de siRNA in vitro et in vivo récemment. Nous voulons mener une enquête plus approfondie sur la livraison de siRNA ciblés en utilisant des dendrimères conjugués avec des ligands spécifiques ou d'anticorps, qui peuvent reconnaître les récepteurs correspondants ou des protéines exprimées à la surface des cellules. De cette façon, le siRNA peuvent être livrés spécifiquement aux cellules d'intérêt, conduisant à une délivrance ciblée, ce qui peut améliorer l'efficacité livraison et de réduire la toxicité en évitant les interactions non spécifiques et à des doses plus faibles. À cette fin, nous avons développé des dendrimères portant une chaîne PEG long et un dendron individu polyvalent. La chaîne PEG est de libérer l'encombrement stérique entre dendrimère et ligand / anticorps, tandis que le dendron multivalent fournit une plate-forme d'une conjugaison contrôlable de ligands. Par ailleurs, nous avons également conçu et synthétisé une autre dendrimères PEGylées portant un groupe thiol libre pour la préparation des anticorps / dendrimère conjuguésWe have demonstrated that structurally flexible poly(amido)amine (PAMAM) dendrimers are efficient siRNA delivery system in vitro and in vivo recently. We would like to undertake further investigation on targeted siRNA delivery using dendrimers conjugated with specific ligands or antibodies, which can recognize the corresponding receptors or proteins expressed on the cell surface. In this way, siRNA can be delivered specifically to the cells of interest, leading to targeted delivery, which can further improve the delivery efficiency and reduce the toxicity by avoiding non-specific interactions and at lower doses. To this end, we have developed dendrimers bearing a long PEG chain and an individual multivalent dendron. The PEG chain is to release the steric congestion between dendrimer and ligand/antibody, whereas the multivalent dendron provides a platform of a controllable conjugation for ligands. Besides, we also designed and synthesized another PEGylated dendrimers bearing a free thiol group for the preparation of antibody/dendrimer conjugates
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Williams, Gareth Rhys. "The synthesis and applications of new organo-phosphorus and organofluorine-phosphorus compounds." Thesis, University of Manchester, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.528265.
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Morgan, Joel Ryan. "The synthesis of glycodendrimers and their applications in carbohydrate-protein interactions and catalysis." Diss., Montana State University, 2006. http://etd.lib.montana.edu/etd/2006/morgan/MorganJ0806.pdf.
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Winchester, Richard. "Synthesis of Elemental Phosphorus and Arsenic Nanostructures." Thesis, Imperial College London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525231.
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Cossairt, Brandi M. (Brandi Michelle). "Niobium-mediated synthesis of phosphorus-rich molecules." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/57702.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2010.Vita. Page 224 blank. Cataloged from PDF version of thesis.
Includes bibliographical references.
The use of a sterically demanding enolate ligand -OC[2Ad]Mes supported by niobium has allowed for the synthesis of (Mes[2Ad]CO) 3Nb=PP7Nb(OC [2Ad]Mes)3 through P4 coupling by a low-valent niobium intermediate. This asymmetric phosphorus-rich cluster harbors a niobium phosphinidene unit bound to a niobium-supported P7 cluster. The phosphinidene terminus was found to react with a range of ketones to give phosphaalkene complexes R2C=PP7Nb(OC[2Ad]Mes) 3. These phosphaalkenes are unstable towards intramolecular rearrangement to give R2CP8Nb(OC[ 2Ad]Mes)3 in which the carbene unit has been internalized into the P8 cage. This rearrangement was studied through both Eyring and Hammett analyses. Structrually the new R2CPsNb(OC[2Ad]Mes)3 are viewed as coordinated-diphosphenes and it was found that the diphosphene unit could be liberated and trapped by reaction with pyridine-N-oxide in the presence of excess 1,3-cyclohexadiene, generating niobium oxo and R2CP8(C 6H8). Searching for new platforms to investigate niobium-phosphorus chemistry led to the synthesis of [Na(THF) 3][P3Nb(ODipp) 3], an anionic cyclo-P3 complex that is accessible in two steps from commercially available reagents. It was discovered that [Na(THF) 3] [P3Nb(ODipp) 3] could function as a source of P3 3-, which has allowed for the synthesis of the tetraatomic molecule AsP 3 as a pure substance for the first time. AsP 3 has been studied by gas-phase electron diffraction, photoelectron spectroscopy, solid-state NMR spectroscopy, raman spectroscopy, as well as high resolution mass spectrometry, and a variety of quantum chemical calculations. Further, a wide array of AsP3 reaction chemistry has been probed including the synthesis and structural characterization of two metal complexes with a coordinated, intact AsP3 ligand. Motivated to explore the chemistry of [Na(THF)3][P3Nb(ODipp) 3] further, a series of investigations were carried out to generate substituted triphosphirene ligands complexed to niobium. In particular Ph3SnP3Nb(ODipp) 3 was prepared and was found to react cleanly and efficiently with pyridine-N-oxide in the presence of an excess of 1,3-cyclohexadiene to generate the niobium oxo complex and Ph3SnP3(C6H8), the product of a Diels-Alder reaction between the liberated triphosphirene and 1,3-cyclohexadiene. This unusual phosphorus-rich molecule was exploited in a number of transformations. One reaction of particular interest was the synthesis of P3Rh(PPh 3)3 from Ph3SnP3(C6Hg) and Wilkinson's catalyst (ClRh(PPh3)3) with loss of 1,3-cyclohexadiene and ClSnPh3- This transformation is an illustrative example of the ability of Ph3SnP 3(C6H8) to act as a P3 transfer agent.
Brandi M. Cossairt.
Ph.D.
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Almeida, Juan Echenique. "Synthesis of polyurethane dendrimers using carbon dioxide as an alternative to phosgene." Thesis, University of Warwick, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247357.
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Lebreton, Sylvian Michel. "Immobilised dendrimers as high-loading solid-phase supports for synthesis and screening." Thesis, University of Southampton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250000.
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Atzori, Simone. "Synthesis of novel calix[4]arene based dendrimers and their biological applications." Thesis, University of East Anglia, 2013. https://ueaeprints.uea.ac.uk/48084/.
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This thesis describes the development and synthesis of multicalixarenes and their application in gene and drug delivery. Chapter 1 provides an introduction to gene therapy and calixarenes. The synthesis of two families of amino functionalised multicalixarenes are described. Evaluation of their toxicity and transfection studies are reported and a number of candidates for development identified. Chapter 2 describes the development of calixarene glycoconjugates using a wide range of approaches. The synthesis of calixarene glycoconjugates through click chemistry is reported and the development of the first multicalixarene glycoconjugate is discussed. Chapter 3 reviews the development of large multicalixarenes assemblies. The synthesis of large (9 and 21 member) click based multicalixarenes is described.
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Nagy, Zsuzsanna tamara. "Synthesis of self-organized dendrimers and dendronized nanohybrids and their physical properties." Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAE020/document.
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Pour ce travail de thèse, nous nous sommes intéressés dans une première partie à la conception et à la synthèse de nouveaux matériaux multifonctionnels (LC, photosensible, systèmes moléculaires dendritiques) capables d'être élaborés en films minces anisotropes et doués de propriétés photo-induites. Nous avons réalisé l'étude complète des propriétés mésomorphes de ces nouveaux matériaux et de dérivés structuraux (en fonction de la connectivité dendritique intrinsèque) par la diffraction des rayons X aux petits angles; l’étude de leurs propriétés optiques a également été effectuée. Dans une seconde partie, nous avons fonctionnalisé des nanoparticules d'or avec des ligands dendritiques mésogènes afin d'organiser ces particules dans des structures mésomorphes. Les objectifs principaux de cette partie sont tout d’abord la synthèse d'une "bibliothèque" de nanoparticules mésomorphes dendronisées, et ensuite la caractérisation de réseaux simples formée par l’auto-assemblage des particules précédentesThe need to expand further the range of mesomorphic organization, develop original materials where different functionalities can be added (i.e. multifunctional), and to design “multitask materials” with tunable properties are particularly interesting and crucial challenges for potential uses in future technologies. On the one hand, we focused on the design and synthesis of multifunctional materials (liquid crystalline, dendritic, photoresponisve) which are suitable for making thin films where photoinduced optical anisotropy and surface relief gratings can be generated. The mesomorphic behaviour of these dendrimers was investigated and also their optical properties. On the other hand, we grafted structurally related protodendritic mesogenic ligands to monodisperse gold nanoparticles to elaborate liquid crystalline hybrids in order to self-organize NPs in periodic arrays. A set of dendronized gold nanohybrids was synthesized to carry out this study
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Khanye, Setshaba David. "Synthesis and Antimalarial evaluation of Gold Thiosemicarbazone Complexes and Polyamine-Thiosemicarbazone Dendrimers." Doctoral thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/6317.
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Malaria still remains one of the most dangerous widespread parasitic diseases in developing nations. Reported alarming figures of malaria infections annually highlight the âgapâ that remains to be filled to rid endemic of malaria. As cases of increasing spread of malaria and the emergence of resistance continue to exert pressure on health systems in most affected areas, novel antimalarial compounds are endlessly needed to overcome the problem of malaria infections. This thesis presents research investigating a series of thiosemicarbazones (TSCs) and their novel gold complexes and dendrimers as potential antimalarial agents. A series of TSCs were synthesised in one step using Schiff base chemistry. On the other hand pyrazoline analogues were obtained in two steps using both Mannich and Schiff base chemistries. A range of gold(I) TSC complexes were achieved by reacting TSCs with the starting gold(I) materials, [AuI(PEt3P)Cl] (4.2), [AuI(THT)Cl] (4.3), [AuI(Ph3P)Cl] (4.5), [AuI(PTA)Cl] (4.24), and C6F5AuI(THT) (4.34). Further reaction of TSCs with starting gold(III) complex 2.15 yielded the corresponding series of gold(III) TSC complexes. All the compounds were characterised by multinuclear NMR and FT-IR spectroscopies, mass spectrometry and elemental analysis. Gold(I) complexes 4.15 and 4.16 were further characterised by single X-ray crystallography. The synthesised ligands and complexes were tested for their antiplasmodial activity against chloroquine-sensitive (D10, 3D7) and chloroquine-resistant (W2, K1) strains of the malaria parasite Plasmodium falciparum. These compounds were also evaluated for inhibitory activity against the malarial cysteine protease (falcipain-2). In most cases gold complexes showed enhanced antiplasmodial activities relative to their corresponding ligands. However, no correlation was found between antiplasmodial activities and the inhibition of falcipain-2 in respect of studied compounds. Reaction of TSC thioesters 6.23 with branched dendritic polyamines (PAs) led to two series of polyamine-TSC dendrimers 6.24 and 6.25 whose chemical structures were elucidated using a range of techniques. Similarly, these dendritic TSCs were also tested for their antiplasmodial activity against the W2 strain. Generally, this class of compounds displayed improved antiplasmodial activities in the mid to low micromolar range. The most active compounds were 6.24c (IC50 = 0.79 ïM) and 6.24d (IC50 = 0.67 ïM), respectively.
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Cohen, Terry Suzanne. "Synthesis and photophysics of 3, 4, 9, 10 perylene tetracarboxylic diimide dendrimers /." Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p3004240.
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Tomcik, Dennis John. "Part 1: Synthesis and Study of Helical Conformation in Chiral, Internally Hydrogen-Bonded Dendrons. Part 2: Synthesis and Study of Liquid Crystalline Dendrimers." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1048787071.
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Qiu, Jieru. "Dendrons phosphorés fluorescents amphiphiles : synthèse, caractérisation, applications en oncologie." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30274.
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Les nanotechnologies ont le grand potentiel de révolutionner des technologies classiques variées, dû au développement de nombreux nanodispositifs et ont été intensément étudiées durant la dernière décade. Parmi les nanoparticules utilisées, les dendrimères et dendrons appartiennent à ce "nano-monde" en vertu de leur taille nanométrique, qui peut être modifiée à volonté, ainsi que par exemple leur multivalence et leurs charges. A l'intérieur de l'espace dendrimère, les dendrimères phosphorés apparaissent comme étant parmi les systèmes dendritiques les plus utiles, grâce à l'extraordinaire réactivité et adaptabilité de la chimie du phosphore. Dans ce mémoire nous décrivons la synthèse de plusieurs familles de dendrons phosphorés fluorescent amphiphiles potentiellement intéressants dans les domaines des nanomatériaux et de la nanomédecine. L'hexachlorocyclotriphosphazene utilisé comme cœur a été substitué par cinq groupements hydroxybenzaldehyde et un monomère tel que le pyrene ou un dérivé maleimide comme entité fluorescente ou l'azabisdimethylphosphonate comme groupement non fluorescent. Ces dendrons ont été préparés jusqu'à la génération 2 selon une voie divergente. La dernière étape a consisté en un greffage d'aminopyrrolidine ou aminopipéridine, suivi par protonation par HCl des groupements amines cycliques terminaux conduisant à la formation de dendrons phosphorés amphiphiles. La caractérisation physico-chimique a été réalisée par tout un ensemble de techniques : RMN, UV, CMC, diffusion dynamique de la lumière, potentiel zéta, microscopie électronique à transmission, fluorescence, dichroïsme circulaire, thermogravimétrie. L'étape suivante a consisté en l'étude des propriétés biologiques. Leur cytotoxicité a été déterminée en utilisant des tests MTT et Alamar Blue, effectués sur onze lignées cancéreuses ou saines (HL-60, HCT-116, A549, MCF7, PC3, U87, K562, K562R, MCR5, MDA-MB231 and HT-29). Des tests d'hémolyse ont été effectués pour tester l'effet des dendrons sur la membrane des cellules. Leur habilité à s'associer à du matériel génétique tels que les petits ARN interférents (siRNA siBCL-xL) a été mise en évidence par des expériences notamment d'électrophorèse sur gel. L'internalisation de ces associations (dendriplexes) dans les cellules tumorales a été suivie par cytométrie en flux. Dans le but de moduler les propriétés anticancéreuses des dendrons fluorescents amphiphiles, des quantum dots de carbone (CQDs) ont été associés avec les dendrons pyrene en présence d'un agent cytotoxique comme la doxorubicine encapsulée dans les micelles formées par les dendron pyrene et les CQDs. [...]Nanotechnologies have the high potential to revolutionize various other classical technologies in many fields, due to the development of numerous nanodevice types, and have been intensively studied over the last decade. Among these nanoparticles, dendrimers and dendrons pertain to the "nano-world" by virtue of their size. Their nanometric sizes can be tailored as well, for instance, their multivalency and charges. Within the dendrimer space, phosphorus dendrimers and dendrons appear to be among the most useful dendritic systems due to the extraordinary reactivity and versatility of the phosphorus chemistry. In this thesis, we designed several families of original amphiphilic fluorescent phosphorus dendrons with interesting potential in the fields of nanomaterials and nanomedicine. Hexachlorocyclotriphosphazene used as a core was linked with five 4-hydroxybenzaldehyde and one monomer (pyrene and maleimide derivatives as fluorescent monomers and azabisdimethylphosphonate derivatives as non-fluorescent monomer). The dendrons were prepared up to generation 2 by a divergent method. The last step is the grafting of amino pyrrolidine or amino piperidine following by protonation with HCl to get the expected cationic amphiphilic fluorescent phosphorus dendrons. Their physical characterization were evaluated through numerous technics: NMR, UV, critical micelle concentration (CMC), dynamic light scattering (DLS), zeta potential, transmission electron microscopy (TEM), fluorescent spectra, circular dichroism and thermogravimetry. In a next step, the biological properties of the dendrons have been examined. The cytotoxicity of dendrons was determined using MTT test and Alamar Blue assay performed on eleven cells lines including both cancer cells and healthy cells (HL-60, HCT-116, A549, MCF7, PC3, U87, K562, K562R, MCR5, MDA-MB231 and HT-29 cells line). Hemolysis assays were used to test the effect of dendrons on the cell membrane. Their ability to bind genetic material was studied by gel electrophoresis using fluorescein-labeled small interference RNA siBCL-xL. Flow cytometry method was used to study the internalization of dendriplexes into tumor cells. In order to modulate the anticancer properties of the fluorescent dendrons, carbon quantum dots (CQDs) were chosen to conjugate with the pyrene dendrons in the presence of a cytotoxic agent like doxorubicin (DOX), physically loaded into 'micelles'. [...]
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Goyal, Poorva. "Development of dendritic and polymeric scaffolds for biological and catalysis applications." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24826.
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Thesis (Ph.D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2008.Committee Chair: Weck, Marcus; Committee Member: Bunz, Uwe H. F.; Committee Member: Dickson, Robert M; Committee Member: Fahrni, Christoph J; Committee Member: Jones, Christopher W; Committee Member: Murthy, Niren.