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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.
1

Photo-active anthracene receptors for s-block and d-block metals

McSkimming, Gordon January 2001 (has links)
No description available.
2

Synthesis and preliminary study of a cryptand designed to allow potassium ion displacement of a fluorescence quencher

Yao, Min January 1988 (has links)
A new cryptand, 1,18-bis[(phenylmethoxy)methyl]-3,16,20,23,26,29,32,35-octaoxatetracyclo-[16.9.9,05,10 09,14]hexatriaconta-5,7,9,11,13-pentaene was synthesized from cis-9,19-bis(benzyloxymethyl)-1,4,7,11,14,17-hexaoxacycloeicosane-9,l9-diyldimethanol and l,5-bis(bromomethyl)naphthlene in the presence of t-butoxide base. The overall syntheses involved five steps. The new cryptand compound has a melting point at 164-1650 C, and the yield was 18.5%. The NMR spectra and the crystal structure determination proved the synthesized cryptand the same as that desinged.Fluorescent measurements were performed with this cryptand. The fluorescence was found to be quenched by cesium ion, and the quenching increased with the increasing of cesium ion concentration. The average quenching of the fully complexed (with Cs +) cryptand was estimated as 20 + 2% by a computerized data fitting program. The complexation constant was determined to be 16 ± 5 M-1. A possible explanation for these observations is presented. / Department of Chemistry
3

I. Functionalization and Investigation of Highly Efficient Hosts for Use in Macromolecular Self-Assemblies and II. The Design and Synthesis of ROMP Imidazolium Systems for Use as Mechanical Actuators

Price, Terry Leon Jr. 09 June 2016 (has links)
Recent advancements in supramolecular chemistry have given a wealth of strongly binding host-guest combinations. However, the deployment of these systems into meaningful constructs has been hindered due to difficulty of synthesis or to the lack of functionality in one or both components. Systems caught in this trap were the pyridyl cryptands of dibenzo-30-crown-10 and bis(m-phenylene)-32-crown-10 paired with paraquat. Exceptionally high association constants in the range of 105 to 106 have been observed for these systems, but their applications have been hindered. Easing the implementation of pyridyl cryptands based on dibenzo-30-crown-10 was made a priority. An efficient method for the synthesis of pyridyl cryptands based on dibenzo-30-crown-10 and bis(m-phenylene)-32-crown-10 made use of the salt pyridinium bis(trifluoromethane)sulfonamide (TFSI) as a template. Optimization of the pyridinium TFSI template allowed for cyclization yields as high as 89%, as well as without the use of a syringe pump. Addressing the concern of functionality, for pyridyl cryptands, chelidamic acid was targeted as a way to build in functionality. Using a chelidamic isopropyl ester, 20 new chelidamic precursors of varying functionality were synthesized. The chelidamic derivatives fell into six groups: potential covalent monomers, initiators, chain terminators, leaving groups, aryl halides and host-guest monomers. In an attempt to boost the association constants of pyridyl cryptands based on dibenzo-30-crown-10 with paraquat, alterations to the paraquat guest were explored. It was found that the association constants could be increased by nearly an order of magnitude. Tweaks to the paraquat included changing the counterion to TFSI, methyl groups to benzyl and allowing for access to more nonpolar solvents that were previously inaccessible, such as solvent change from DCM to acetone. Two new biscryptands and two new bisparaquat TFSI monomers were synthesized. Using these monomers supramolecular polymers were synthesized and characterized. Fibers of these polymers drawn from concentrated solutions were found to be flexible and one such polymer solution was found to have an upper log / log specific viscosity–concentration slope of 3.55, which is the theoretical maximum. Additionally, a biscryptand was used to produce a chain extended polymer. Using a fundamental understanding of host-guest chemistry, work was conducted on the synthesis of norbornene monomers and polymers with pendant imidazolium tethered by ethyleneoxy linkages to aid in the stabilization of the imidazolium cation. Through the use of ethyleneoxy linkages, the free anion content and conductivity was increased. Imidazolium monomer and polymer conductivities ranged up to nearly 10-4 S/cm. Furthermore, it was determined that as long as the ethyleneoxy spacer between the norbornene and imidazolium was two units or greater, similar properties were obtained for both the monomer and corresponding polymer. Expanding the work further, the imidazolium monomers were incorporated as a soft segment into a triblock copolymer to produce a single direction mechanical actuator. / Ph. D.
4

Synthesis and host-guest interaction of cage-annulated podands, crown ethers, cryptands, cavitands and non-cage-annulated cryptands.

Chen, Zhibing 05 1900 (has links)
Symmetrical cage-annulated podands were synthesized via highly efficient synthetic strategies. Mechanisms to account for the key reaction steps in the syntheses are proposed; the proposed mechanisms receive support from the intermediates that have been isolated and characterized. An unusual complexation-promoted elimination reaction was studied, and a mechanism is proposed to account for the course of this reaction. This unusual elimination may generalized to other rigid systems and thus may extend our understanding of the role played by the host molecules in "cation-capture, anion-activation" via complexation with guest molecules. Thus, host-guest interaction serves not only to activate the anion but also may activate the leaving groups that participate in the complexation. Complexation-promoted elimination provides a convenient method to desymmetrize the cage while avoiding protection/deprotection steps. In addition, it offers a convenient method to prepare a chiral cage spacer by introducing 10 chiral centers into the host system in a single synthetic step. Cage-annulated monocyclic hosts that contain a cage-butylenoxy spacer were synthesized. Comparison of their metal ion complexation behavior as revealed by the results of electrospray ionization mass spectrometry (ESI-MS), alkali metal picrate extraction, and pseudohydroxide extraction with those displayed by the corresponding hosts that contain cage-ethylenoxy or cage-propylenoxy spacers reveals the effect of the length of the cage spacer upon the host-guest behavior. A series of cage-annulated cryptands, cavitands and the corresponding non-cage-annulated model compounds have been synthesized. These host molecules display unusual behavior when examined by using ESI-MS techniques, i.e., they bind selectively to smaller alkali metal ions (i.e., Li+ and Na+), a result that deviates significantly from expectations based solely upon consideration of the size-fit principle. It seems likely that this behavior results from the effect of the host topology on host-guest behavior. A series of non-cage-annulated cryptands also have been synthesized. These compounds can serve as starting materials for cavitand construction.
5

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.
6

The Chemistry of Fullerenes, Polymers, and Host/Guest Interactions

Schoonover, Daniel Vernon 03 March 2015 (has links)
The exploitation of the relationship between the chemical and physical properties of materials is the hallmark of advancing science throughout the world. The basic understanding of how and why molecules react and interact with each other in different environments allows for the discovery and implementation of new materials and devices that not only advance the state of human life but continually change the planet. The work described in this dissertation generally falls under three diverse categories: functionalization of fullerenes, investigation of host/guest interactions in solution, and the synthesis and characterization of ion containing polymers. The separation and functionalization of fullerenes is a recent and exciting area of research. The separation methods outlined are intended to increase the availability of endohedral metallofullerenes by decreasing their cost of production. Functionalized fullerene species were achieved through Bingel and Prato reactions to provide materials with novel functional groups. These materials may be further utilized in photovoltaic or other organic electronic devices. The characterization of noncovalent interactions between different molecules in solution is the focus of supramolecular chemistry. Isothermal Titration Calorimetry stands out as one of the best, among the many methods used to elucidate the characteristics of these systems. The binding of bis- imidazolium and paraquat guests with macrocyclic host molecules has been explored in this work. The measurements of the association constants for these systems will aid in the ongoing synthesis of new host/guest systems. Ion containing polymers were synthesized and characterized for their use in electroactive devices. Imidazolium containing polymers with bulky anions were synthesized on low glass transition polymer chains. These materials had enhanced ion conductivity and may eventually be used in electronic actuator materials. / Ph. D.
7

Synthesis and studies of new optimised chelating agents for targeting chemokine receptor CXCR4 / Synthèse et étude de nouveaux agents chélatants optimisés ciblant le récepteur de chimiokine CXCR4

Désogère, Pauline 22 November 2012 (has links)
L’objectif de ce travail de thèse était de développer des outils pour détecter et traiter le cancer àun stade précoce. Nous avons donc entrepris la synthèse de nouveaux radiopharmaceutiques ciblantspécifiquement le récepteur CXCR4, en utilisant le savoir-faire et l'expertise de notre groupe dans lasynthèse et la fonctionnalisation des polyazacycloalcanes. Nous avons travaillé simultanément surdeux aspects : l’agent chélatant et la molécule vectrice.Dans un premier temps, les travaux ont concerné la conception, la synthèse et la caractérisationde nouveaux macrocycles à fort potentiel pour la chélation du cuivre et du gallium. Nous avons toutd’abord développé une nouvelle voie de synthèse permettant d’accéder à des dérivés homocyclènesC-functionnalisés. Nous nous sommes ensuite intéressés aux dérivés du 1,4,7-triazacyclononane(TACN). En optimisant une voie de synthèse déjà développée au laboratoire, nous avons facilitél’accès à des dérivés TACN N- et C-fonctionnalisés. Nous avons ainsi préparé une série denouveaux agents chélatants bifonctionnels adaptés pour la complexation du cuivre ou du gallium, envariant la nature de la fonction de greffage et des bras coordinants. Nous avons également réalisé lasynthèse de nouveaux cryptands en série cyclène et nous avons étudié leur propriété decomplexation vis à vis du cuivre.Dans un second temps, nous avons développé une nouvelle famille d’agents imageants duCXCR4 en modifiant la structure des AMD3100 et AMD3465. Ce travail a tout d’abord nécessité lamise au point de nouvelles méthodes de fonctionnalisation de ces structures. Nous avons ainsi pupréparer de nouveaux synthons porteur d’une fonction de greffage dans les deux séries. Nous avonsensuite introduit différentes sondes imageantes, telles que des chélates adaptés pour la complexationdu cuivre, gallium et indium ainsi que des sondes fluorescentes de type bodipy / The objective of this thesis work was to develop CXCR4-targeted tools to localize and treat cancer at an early stage. In this line, we investigated the synthesis of new target-specific radiopharmaceuticals. The work focused on two main axes, i.e. the chelating agent and the carrier, by using the know-how and the expertise of our group in polyazacycloalkanes synthesis and functionalization. In the first part, we were interested in developing new macrocyclic scaffolds of high potential for copper and gallium chelation. We first focused on the development of a new powerful route towards selectively functionalized constrained homocyclens. The second part was based on C-functionalized 1,4,7-triazacyclononane (TACN) and its derivatives. From a synthetic route previously developed in our group, we were able to facilitate and optimize the synthesis of selectively N- and C-functionalized TACN. By varying the grafting functions and the pendant coordinating arms, we prepared several really promising bifunctional chelating agents for copper and gallium chelation. We also investigated the synthesis of new cryptands based on cyclen and we studied their properties towards copper complexation. In the second part of this thesis work, we were interested in generating a new family of imaging agents based on well-known CXCR4 antagonists, i.e. AMD3100 and AMD3465. The access towards these agents first required the preparation of original building blocks by modification of the AMD3100 and AMD3465 cores. The conjugation of such platforms onto the appropriate probe enabled the synthesis of various systems for optical and nuclear imaging. Thus, we were able to introduce a bodipy dye and several chelators adapted for gallium, copper and indium chelation
8

Nouvelles architectures fonctionnelles pour la reconnaissance moléculaire, systèmes conjugués à faible Gap et matériaux pour électrode avancés

Pop-Piron,, Flavia-Florina 08 December 2009 (has links) (PDF)
La thèse intitulée " New Functional Architectures for Molecular Recognition, Low Band Gap Conjugated Systems and Advanced Electrode Material " est structurée en quatre chapitres traitant de a) structures supramoléculaires tels que cryptands et bis-macrocycles; b) tetrahalo-1,3-diènes chiraux stériquement encombrées; c) blocs pour la synthèse de polymères faible gap conjugués d) architectures 3D conjugués à base de bithiophènes portant des EDOTs terminaux. Dans le premier chapitre, on présente deux nouvelles séries de précurseurs macrocycliques tripodaux possédant une symétrie C3 construites à partir de 1,3,5-triazine avec des groupes fonctionnels réactifs aux extrémités des bras. Les structures supramoléculaires obtenues par des réactions de couplage acétylénique catalysées par Cu sont également présentées. Les cryptands ont été fermés par dimérisation intermoléculaire et les bis-macrocycles ont été formés par des couplages intramoléculaires suivis par dimérisation intermoléculaire. Le deuxième chapitre présente l'étude de nouveaux atropisomères à base d'EE-tetrahalo-1,3- butadiène y compris la séparation des énantiomères, la détermination des barrières de rotation et des configurations absolues. Le troisième chapitre a été consacré à la synthèse des blocs à base de benzo [2,1-b:3,4-b']- dithiophène-4,5-dione utilisés pour obtenir des polymères conjugués à faible gap pouvant fonctionner comme matériau actif dans des cellules solaires organiques. Dans le dernier chapitre on décrie la synthèse et les propriétés électroniques de différents types de nouvelles architectures 3D conjuguées à base de bithiophène comportant des unités EDOTs terminales, en vue de la génération électrochimique de réseaux microporeux électroactifs conjugués. Il est montré que la taille, la surface active et les propriétés électroniques dépendent de la nature des blocs utilisés pour la construction des bras latéraux.
9

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.
10

Synthèse et étude de nouveaux agents chélatants optimisés ciblant le récepteur de chimiokine CXCR4

Désogère, Pauline 22 November 2012 (has links) (PDF)
L'objectif de ce travail de thèse était de développer des outils pour détecter et traiter le cancer àun stade précoce. Nous avons donc entrepris la synthèse de nouveaux radiopharmaceutiques ciblantspécifiquement le récepteur CXCR4, en utilisant le savoir-faire et l'expertise de notre groupe dans lasynthèse et la fonctionnalisation des polyazacycloalcanes. Nous avons travaillé simultanément surdeux aspects : l'agent chélatant et la molécule vectrice.Dans un premier temps, les travaux ont concerné la conception, la synthèse et la caractérisationde nouveaux macrocycles à fort potentiel pour la chélation du cuivre et du gallium. Nous avons toutd'abord développé une nouvelle voie de synthèse permettant d'accéder à des dérivés homocyclènesC-functionnalisés. Nous nous sommes ensuite intéressés aux dérivés du 1,4,7-triazacyclononane(TACN). En optimisant une voie de synthèse déjà développée au laboratoire, nous avons facilitél'accès à des dérivés TACN N- et C-fonctionnalisés. Nous avons ainsi préparé une série denouveaux agents chélatants bifonctionnels adaptés pour la complexation du cuivre ou du gallium, envariant la nature de la fonction de greffage et des bras coordinants. Nous avons également réalisé lasynthèse de nouveaux cryptands en série cyclène et nous avons étudié leur propriété decomplexation vis à vis du cuivre.Dans un second temps, nous avons développé une nouvelle famille d'agents imageants duCXCR4 en modifiant la structure des AMD3100 et AMD3465. Ce travail a tout d'abord nécessité lamise au point de nouvelles méthodes de fonctionnalisation de ces structures. Nous avons ainsi pupréparer de nouveaux synthons porteur d'une fonction de greffage dans les deux séries. Nous avonsensuite introduit différentes sondes imageantes, telles que des chélates adaptés pour la complexationdu cuivre, gallium et indium ainsi que des sondes fluorescentes de type bodipy.

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