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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Synthesis of Polycatenanes Through Molecular Design

Wu, Qiong 08 February 2017 (has links)
No description available.
12

Efficient Syntheses of Strong Binding Cryptands and their Derivatives for Supramolecular Polymer Synthesis

Pederson, Adam Micheal-Paul 07 March 2009 (has links)
Production of efficiently synthesizable, strongly associating crown ether-based cryptands is desired for pseudorotaxane complexation of bipyridinium guests to produce suprapolymers and supramolecularly-linked block copolymers. Cryptands based on bis(meta-phenylene)-32-crown-10 (BMP32C10) were synthesized. The functionality of phenylenemethanol-BMP32C10 cryptand III-3 (Ka = 2.0 x 104 M-1) did not negatively affect binding strength, although the strength of complexation is marginal to achieve the desired suprapolymers. The cryptand dimethylpyridyl-BMP32C10 IV-2 was synthesized in an attempt to improve over the binding ability of the pyridyl-BMP32C10 cryptand IV-1; instead, interesting host design insights were discovered as binding strengths were reduced over 1000-fold. The crystal structure of IV-2 shows acyl-aryl conjugation which limits the host's ability to accept guests. Synthesis of larger cis-di(carbomethoxybenzo)-3n-crown-n crown ethers was explored using the high concentration, template technique previously reported for cDB24C8 diester. cDB30C10 diester (V-1c) was produced in 93% yield; the desired pyridyl-cDB30C10 cryptand V-12 binds paraquat strongly (Ka = 1-2x105 M-1) and diquat stronger than any other host (Ka = 1.9x106 M-1), both in 1:1 fashions; association constants were measured by ITC. X-ray crystallography of the complexes shows the cryptand's para arm is too far away to interact with paraquat and the host has numerous bifurcated interactions with diquat, explaining the difference in binding strengths. Syntheses of the regioisomers of cDB27C9 diester was also explored; the cyclization yields (cDB27C9S, VI-2: 59% and cDB27C9L, VI-3: 44%) are lower, likely due to poor attack angles due to mismatched arm length in cyclization, than the equivalent length ethyleneoxy-armed cDB24C8 and cDB30C10. Modeling of the cryptand isomers, pyridyl-cDB27C9S and pyridyl-cDB27C9L, showed that the former should improve para arm interaction with paraquat, but should be sterically hindered for diquat and the latter should have a highly flexible, poorly preorganized interaction with either type of guest. ITC, MS, and crystallography data supported the predictions. Derivatization of the pyridyl-cDB30C10 cryptand V-12 was explored using chelidamic acid (VII-1). Schemes yielding alcohol, alkyl halide, alkyne, and TEMPO functionality were followed, but failed. Currently, functionalized cryptand derivatives have not been achieved, future directions are proposed. / Ph. D.
13

Příprava a studium vlastností polymerů na bázi bis(terpyridyl)fluorenů / Preparation and characterization of bis(terpyridyl)fluorene based polymers

Hrma, Martin January 2016 (has links)
The diploma thesis presents the preparation of ,-bisterpyridinylfluorenes (unimers) containing fluorene unit in the central block either directly attached to terpyridine (tpy) end groups or via 1,4-phenylene or thiophene-2,5-diyl linker. Synthesized unimers were subsequently used for the preparation of metallo-supramolecular polymers with Zn2+ and Fe2+ ions. The prepared unimers were characterized by NMR, IR and HR-MS, their optical properties were investigated using absorption and emission spectroscopy and cyclic voltammetry. Molecular weight distribution for the prepared Fe-polymers was determined by GPC. The number-average degree of polymerization equal to 7 for an equimolar ratio between unimer and Fe2+ in a diluted solution was determined for polymers composed of unimer with thiophene-2,5- diyl linker. By using the viscometric measurements the ongoing constitutional dynamics in solutions of metallo-supramolecular polymers was proven. The overstoichiometric amount of metal ions in solution resulted in equilibrium shortening of the polymer chains together with end-capping of terminal tpy ligands by Mt2+ ions. Unimer with thiophene-2,5-diyl linker exhibited unique properties involving significantly red-shifted absorption and emission maxima, as well as the different behavior during assembling...
14

Synthesis and self-assembly of triarylamines modified with nucleobases / Synthèse et auto-assemblage de triarylamines modifiées par des nucléobases

Cao, Qing 18 January 2017 (has links)
Les triarylamines sont de petites molécules largement utilisées comme porteurs de charges dans le domaine de l'électronique organique, car elles présentent des mobilités de transport de trous élevées. En 2010, notre groupe a démontré pour la première fois que les molécules de triarylamine décorées avec des groupements amide subissent une polymérisation supramoléculaire. D'autre part, les propriétés de reconnaissance des résidus de nucléobases ont été largement utilisées au cours des 25 dernières années pour déclencher des processus d'auto-assemblage de polymères ou de petites molécules en polymères supramoléculaires bien définis. Dans cette thèse, une série de molécules triarylamine décorées avec des amides sur leurs chaînes latérales avec différentes nucléobases comme la guanine, la thymine et la cytosine ont été synthétisées. Nous avons démontré que les monomères de triarylamine conservent leurs propriétés d'auto-assemblage dans les solvants chlorés lors de l'irradiation lumineuse, à condition que le résidu de la nucléobase n'affecte pas les interactions non covalentes nécessaires pour l'auto-assemblage du cœur de triarylamine. En outre, nous avons démontré que la présence d'amines primaires sur le résidu de la nucléobase interdit la formation de structures auto-assemblées dès qu'elles ne sont pas incorporées dans des réseaux de liaisons hydrogène. Dans un deuxième chapitre, nous avons ensuite étudié les auto-assemblages de nos molécules triarylamine-nucléobase dans des solvants organiques en utilisant des ions ou de petites molécules comme matrice. Tout d'abord, la polymérisation supramoléculaire de la triarylamine-monothymine à l'aide de mélamine dans divers solvants a été étudiée. Par ailleurs, l'influence sélective des ions de mercure sur les propriétés sensibles légères de triarylamine-monothymine a été soigneusement analysé. Enfin, les polymères supramoléculaires hybrides de triarylamine-monoguanine conjugué en absence et en présence d'ions potassium ont été obtenus. En particulier, nous avons décrit le premier exemple de polymères supramoléculaires construits à partir de mélamine dans des solvants organiques. Dans l'ensemble, l'impact de ce travail est triple: a) il conduit à une meilleure compréhension du comportement d'auto-assemblage des conjugués de triarylamine, b) il influence la conception des structures de triarylamine auto-assemblées et c) il offre de nouvelles approches pour l'auto-assemblage des molécules de triarylamine. / Triarylamines are small molecules widely used as charge carriers in the field of organic electronics as they display high hole-transport mobilities. In 2010, our group demonstrated for the first time that chemically-tailored triarylamine amide molecules undergo supramolecular polymerization. On the other hand, the recognition properties of nucleobase residues have been widely used in the last 25 years to trigger self-assembling processes of polymers or small molecules into well-defined supramolecular polymers.In this thesis, a series of triarylamine amide molecules decorated on their side chains with various nucleobases such as guanine, thymine and cytosine have been synthesized. We have demonstrated that the triarylamine monomers retain their self-assembling properties in chlorinated solvent upon light irradiation, provided that the nucleobase residue does not affect the non-covalent interactions necessary for the self-assembly of the triarylamine core. In addition, we have demonstrated that the presence of primary amines on the nucleobase residue prohibit the formation of self-assembled structures, as soon as they are not embedded in hydrogen bonding arrays. In a second chapter, the templated self-assemblies of our triarylamine-nucleobase molecules in organic solvents were studied. Firstly, templated supramolecular polymerization of triarylamine-monothymine using melamine in various solvents was investigated. Besides, selective influence of mercury ion on the light responsive properties of triarylamine-monothymine was analyzed carefully. At last, hybrid supramolecular polymers of triarylamine-monoguanine conjugate in absence and in presence of potassium ion were obtained. In particular, we have described the first example of supramolecular polymers build from melamine in organic solvents. Overall, the impact of this work is three-fold: a) it leads to a better understanding of the self-assembly behavior of triarylamine conjugates, b) it influences the design of self-assembling triarylamine structures and c) it offers new approaches for the self-assembly of triarylamine molecules.
15

DYNAMICS OF POLYMER SELF-ASSEMBLY BY COMPUTER SIMULATION

LI, ZHENLONG 21 March 2011 (has links)
No description available.
16

Multifunctional Metallo-Supramolecular Matrials and Sensors

Burnworth, Mark Gross 14 March 2011 (has links)
No description available.
17

Host-Guest Systems Based on Crown Ether, Cryptand, and Pseudocryptand Hosts with Paraquat, Diquat, Secondary Ammonium, and Monopyridinium Salt Guests

Huang, Feihe 25 March 2005 (has links)
Supramolecular host-guest chemistry is a topic of great current interest. However, the further development of host-guest chemistry is still limited by the number of available host-guest recognition motifs. This makes it necessary and valuable to find new host-guest recognition motifs and apply known host-guest recognition motifs in the preparation of novel supramolecular systems. By comparing the crystal structures of the host and its taco complex, we proved that folding is a necessary step during the formation of taco complexes. Based on the known bis(m-phenylene)-32-crown-10/paraquat recognition motif, the first solid-state supramolecular poly(taco complex) was prepared. We demonstrate not only that bis(m-phenylene)-32-crown-10-based cryptands are powerful hosts for paraquat derivatives compared with the simple crown ether, but also that cooperative complexation can be obtained with the cryptand structure. It was shown that the significant improvement in complexation was the result of the combination of the preorganization of the cryptand hosts and the introduction of additional and optimized binding sites. Furthermore, it was demonstrated that improved complexation of bis(secondary ammonium) and bisparaquat salts could also be achieved by the formation of the pseudocryptand structure. We also prepared two dimers of inclusion cryptand/paraquat complexes driven by dipole-dipole and face-to-face p-stacking interactions. An interesting complex based on dibenzo-24-crown-10 and diquat was prepared. In its crystal structure the diquat guest lies in the concave cavity provided by two dibenzo-24-crown-8 hosts. Monopyridinium-based [2]- and [3]-pseudorotaxanes were prepared based on the newly discovered bis(m-phenylene)-32-crown-10/monopyridinium salt and cryptand/monopyridinium salt recognition motifs. Inspired by the formation of solid-state taco complexes between bis(m-phenylene)-32-crown-10 and paraquat derivatives, we designed and synthesized the first cylindrical bis(crown ether) host for paraquat derivatives and studied its complexation with paraquat. We prepared three slow-exchange C3-symmetric inclusion complexes based on a newly discovered cryptand/trispyridinium recognition motif, in which 1,3,5-trispyridiniumbenzene salts act as guests. Finally the application of several new and known recognition motifs in the preparation of a supramolecular poly[3]pseudrotaxane, and the first pseudorotaxane-type supramolecular star-shaped polymer, and the first supramolecular hyperbranched polymer was discussed. / Ph. D.
18

Příprava a vlastnosti stavebních bloků speciálních polymerů / Preparation and properties of building blocks of specialty polymers

Šichová, Kristýna January 2014 (has links)
This Diploma Thesis presents results obtained by solution of two partial projects: a) Preparation of monomers from renewable sources using metathesis and tandem hydrogenation catalyzed with ruthenium compounds - project solved during my Erasmus stay at the Université de Rennes 1 in France; b) Preparation and properties of ,-bis(tpy)quarterthiophene oligomers carrying ionic side groups as oligomonomers for polyelectrolyte conjugated dynamers - project solved at the Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague. Project a): Self-metathesis of 1,2-epoxyhex-5-ene (but-3-enyloxirane) and its cross-metathesis with methyl acrylate and acrylonitrile catalyzed with ruthenium compounds as well as tandem design of these metatheses and consecutive hydrogenation of their products by gaseous hydrogen have been optimized. The following influences have been studied and tuned: (i) type of the catalyst (Grubbs, Hoveyda, Zhan) and its concentration and method of dosing, (ii) concentration of reactants and additives, (iii) type of solvent, and (iv) reaction temperature. Reactions were monitored by the GC, GC and MS methods and the products were characterized by the NMR method. Methyl 6,7-epoxyheptanoate (methyl 5-oxiranylpentanoate) obtained by the tandem...
19

Platinum complexes and their luminescent assemblies / Complexes de platine et leurs assemblages luminescents

Aliprandi, Alessandro 30 October 2015 (has links)
Cette thèse porte sur la synthèse et la caractérisation photophysique d'une série de composés neutres luminescents de platine (II) contenant un ligand tridentate dianionique chromophore N-donneur et un ligand auxiliaire monodentate. Les composés montrent un changement notable des propriétés de photoluminescence selon l'auto-assemblage en raison de la formation d'interactions intermoléculaires non covalentes faibles telles que metal-metal et π-π. Nous avons démontré comment les complexes de Pt (II) peuvent être auto-assemblés d'une manière contrôlée et précise en jouant sur les facteurs cinétiques et thermodynamiques, ainsi que la morphologie des différents ensembles étudiés. Ces approches ont conduit à des matériaux avec des propriétés améliorées et uniques tels que le mécano-chromisme, ainsi que l'absorption et l'émission de la lumière polarisée. Les composés étudiés et leurs assemblages sont utiles non seulement pour le développement de nouveaux matériaux fonctionnels supramoléculaires en équilibre et hors- équilibre, mais aussi pour des applications en bio-imagerie. / This thesis focuses on the synthesis and the photophysical characterization of a series of luminescent neutral Pt(II) compounds containing a tridentate dianionic N-donor chromophoric ligand and a monodentate ancillary moiety. The compounds exhibited notable change of the photoluminescence properties upon self-assembly due to the establishment of weak non-covalent intermolecular interactions – metal-metal and π-π. We demonstrated how Pt(II) complexes can be self-assembled in a controlled and precise manner by playing with kinetic and thermodynamic factors and the morphology of the different assemblies investigated. Such approaches led to materials with enhanced and unique properties such as mechanochromism and polarized light absorption and emission. The investigated compounds and their assemblies were useful for the development of novel functional supramolecular materials in and out of the equilibrium as well as for bioimaging application.
20

Macroscopic amplification of nanoscopic motions induced by molecular machines / Amplification macroscopique de mouvements nanométriques induits par des machines moléculaires

Goujon, Antoine 20 September 2016 (has links)
Ces vingt dernières années, le domaine du design et de la synthèse de machines moléculaires complexes a fait d’énormes progrès,souvent inspiré par la beauté de la machinerie présente dans les systèmes vivants. Cependant, l’amplification des mouvements d’un grand nombre de machines moléculaires à des échelles de tailles largement supérieures à leurs dimensions restent un défi théorique et expérimental ambitieux et ardu. Ce travail décrit comment l’organisation de machines et moteurs moléculaires dans des réseaux polymères supramoléculaires ou covalents permet de synthétiser des matériaux dans lesquels leurs mouvements individuels nanométriques sont amplifiés jusqu’à l’échelle macroscopique. Les trois premiers chapitres décrivent l’utilisation d’une architecture de type [c2]daisy chains, une molécule capable d’effectuer des contraction/extensions similaires aux mouvements des sarcomères présents dans les muscles, dans des réseaux polymères supramoléculaires et covalents. Leur introduction dans des polymères supramoléculaires à liaisons hydrogène basées sur le motif de reconnaissance uracil:2,6-diacetylaminopyridine associé à des interactions latérales tel que les interactions π résulta en la formation de fibre supramoléculaires contractiles dont la taille et la morphologie a pu être commuté entre deux états étendus et contractés. L’incorporation de motifs uréidopyrimidinone comme connecteur supramoléculaire en revanche donna accès à des gels supramoléculaires, évoluant vers un état liquide lors de la contraction des chaines polymères. Finalement, l’inclusion de daisy chains dans un réseau polymère 3D a donné accès à un gel chimique. Ce matériau a pu être contracté et étendu à l’échelle macroscopique grâce à l’action combinée des machines moléculaires le constituant.Le quatrième chapitre est dédié à l’amélioration d’un gel contractile basé sur l’utilisation de moteurs moléculaires rotatif comme noeud de réticulation d’un réseau polymère. Une unité modulatrice, capable d’être commuté entre un état “ouvert” et “fermé”, a été introduite dans le réseau aux côtés du moteur. Le modulateur dans son état “fermé” permet aux moteurs moléculaires de contracter efficacement le réseau, tandis que dans son état ouvert il permet aux chaines de se dérouler alors que le moteur ne tourne pas, ce qui provoque l’extension du réseau qui retourne à sa taille initiale. En résumé, le travail décrit dans ce manuscrit illustre que des machines moléculaires soigneusement conçue peuvent être introduites dans des réseaux polymères, fournissant des matériaux dont les propriétés macroscopiques sont affectées par les mouvements nanoscopiques de ses constituants. Ces résultats fournissent des pistes et une base fondamentale pour l’élaboration d’une nouvelle classe de matériaux contractiles basés sur des machines moléculaires. / The last twenty years have seen tremendous progresses in the design and synthesis of complex molecular machines, often inspired by the beauty of the machinery found in biological systems. However, amplification of the molecular machines motion over several orders of magnitude above their typical length scale is still an ambitious challenge. This work describes how self-organization of molecular machines or motors allows for the synthesis of materials translating the motions of their components into a macroscopic response. The three first chapters describe the use of a [c2]daisy chains architecture, a molecule able to perform contraction/extension motions similarly to the sarcomere units of muscles, into systems such as supramolecular polymers and covalent networks. Their inclusion into hydrogen bonding supramolecular polymers based on the uracil:2,6-diacetylaminopyridine recognition motifs combined with lateral interactions such as π-stacking provided micrometric muscle-like fibers contracting and extending upon deprotonation and protonation.The incorporation of ureidopyrimidone moieties as supramolecular connectors yielded highly organized gels, which evolved to a liquidstate upon contraction of the polymer chains. Finally, covalent poly[c2]daisy chains were synthesized and investigated, notably the formation of a 3D network swelling into a gel. This material could contract and extend at the macroscopic scale upon contraction and extension of the molecular machines used as monomers. Finally, a fourth chapter is dedicated to the improvement of contractile chemical gels made by using a molecular motor as reticulating nodes. A modulating unit, able to be switched between a “closed” and an “opened” state, was introduced into the polymer network along with the motor. The locked structure in the “closed” state allowed contraction of the gel upon rotation of the molecular motors, while the “opened” state allowed unwinding of the entangled polymer chains and extension of the gel when the motor is off. Overall, the work presented in this manuscript demonstrates that carefully designed molecular machines can be incorporated into large supramolecular or covalent assemblies, providing materials which collective motions alter their macroscopic properties. These results provide valuable insights for the elaboration of a new class of muscle-like materials based on molecular machines.

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