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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.
171

Poly (squaramides): Synthesis, Anion Sensing, and Self-assembly

Rostami, Ali 31 August 2012 (has links)
The focus of the research presented in this thesis is the design, synthesis, and anion recognition properties of a structurally novel class of poly(amides) that incorporates the diaminocyclobutenedione (squaramide) group into the polymer backbone. In Chapter 1, a brief overview of different anion-responsive synthetic macromolecules is presented. Emphasis is placed on the wide structural diversity of the polymers, the mechanisms of their anion-induced responses, and features such as signal amplification, multivalency, and cooperative behavior that can be exploited productively in the context of anion recognition and sensing. Chapter 2 describes a new method for the regioselective preparation of squaramides, using Lewis acid-catalyzed condensations of diethyl squarate and different anilines. Zinc trifluoromethanesulfonate promotes efficient condensations of anilines with squarate esters, providing access to symmetrical and unsymmetrical squaramides in high yields from readily available starting materials. Colorimetric anion-sensing behavior and computational studies illustrating the enhanced hydrogen bond donor ability and acidity of squaramides in comparison to ureas are presented. In Chapter 3, the application of the synthetic method described above to the selective preparation of polysquaramides composed of 1,2-isomeric repeat units is described. The optical, thermal and aggregation properties of these materials are also discussed. Finally, Chapter 4 describes self-assembly properties as well as applications of these materials in the area of anion recognition and sensing. Incorporating an anion-binding squaramide group into a polymeric architecture results in drastic alterations in the selectivity and magnitude of its anion-induced response, resulting in a sensitive and discriminating turn-on fluorescence sensor for dihydrogenphosphate ions. This unusual behavior is the result of a cooperative, anion-triggered aggregation process that was further probed by dynamic light scattering (DLS), transmission electron microscopy (TEM) and laser confocal microscopy.
172

Metallocene receptors for neutral molecules

Westwood, Joanna January 2001 (has links)
No description available.
173

Platinum-ligand PI bonding interactions the ligand-to-ligand charge transfer transitions and supramolecular chemistry of platinum(II) acetylide and thiolate complexes /

Law, Yuen-chi. January 2006 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.
174

Experimental contributions to the theory and application of molecular recognition

Hughes, Andrew Dike, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.
175

Supramolecular block and random copolymers in multifunctional assemblies

Burd, Caroline Glenn January 2008 (has links)
Thesis (Ph.D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2009. / Committee Chair: Marcus Weck; Committee Member: Bunz, Uwe; Committee Member: Collard, David; Committee Member: Jones, Christopher; Committee Member: Payne, Christine
176

Synthesis and study of heteroatomic spirocyclic scaffolds

Hilmey, David George, January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 211-219).
177

Aromatic electron donor-acceptor interactions in novel supramolecular assemblies

Reczek, Joseph James, January 1900 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.
178

Design and analysis of self-assembling protein systems

Valkov, Eugene January 2007 (has links)
No description available.
179

Níquel (II) e moléculas orgânicas multidentadas como building blocks na construção de sólidos de coordenação porosos /

Fernandes, Ronaldo Júnior. January 2012 (has links)
Orientador: Regina Célia Galvão Frem / Banca: Rafael Sá de Freitas / Banca: Célia Machado Ronconi / Resumo: Este trabalho contempla a síntese e caracterização espectroscópica, estrutural, morfológica e térmica de novos polímeros de coordenação de níquel(II) contendo espaçadores nitrogenados lineares (4-aminopiridina, pirazina, trans-1,2- bis(4-piridil)etileno) e os ânions dicarboxílicos oxalato e malonato. A ideia consiste na preparação de sólidos de coordenação que apresentem simultaneamente porosidade e propriedades magnéticas. Em uma segunda etapa, o estudo foi estendido para outros centros metálicos bivalentes, paramagnéticos, e de geometria preferencialmente octaédrica (manganês, cobalto, cobre). A parte final do trabalho contemplou a investigação do comportamento magnético dos sólidos de níquel(II) obtidos e, também dos sistemas MT/mal/4-apy (MT = Mn, Co, Ni, Cu), através de medidas de susceptibilidade magnética a baixa temperatura, realizadas pelo grupo do Prof. Dr. Rafael Sá de Freitas do Instituto de Física da USP-SP / Abstract: This work describes the synthesis and spectroscopic, structural, morphological and thermal characterization of new coordination polymers of nickel (II) containing nitrogen linear spacers (4-aminopyridine, pyrazine, trans-1,2-bis (4-pyridyl) ethylene) and the dicarboxylic anions oxalate and malonate. The main goal consists in the preparation of coordination solids exhibiting both porosity and magnetic properties. In a second step, the study was extended to other divalent paramagnetic metal centers, with preferably octahedral geometries (manganese, cobalt, copper). The final part of the work included the investigation of the magnetic behavior of the obtained nickel(II) solids and also of the MT/mal/4-apy systems (TM = Mn, Co, Ni, Cu) through the magnetic susceptibility measurements low temperature, performed by the group of the Prof. Dr. Rafael Sá de Freitas of the Institute of Physics, USP-SP / Mestre
180

Halogen- and hydrogen-bonding cyclic and interlocked hosts for anion recognition and sensing

Gilday, Lydia C. January 2013 (has links)
This thesis describes the synthesis of macrocyclic and interlocked receptors which exploit halogen- and hydrogen-bonding intermolecular interactions for anion recognition. <strong>Chapter One</strong> introduces the field of supramolecular chemistry, with particular focus on applications of host–guest chemistry to anion coordination and anion templation in the construction of mechanically interlocked molecules. <strong>Chapter Two</strong> details the synthesis of a series of cyclic and cage-like porphyrin-based receptors which bind anions through halogen- and hydrogen-bonding interactions. The ability of these receptor systems to bind and sense anionic guest species is investigated and comparisons between hydrogen- and halogen-bonding are discussed. <strong>Chapter Three</strong> reports anion-templated pseudorotaxane assemblies stabilised by both halogen- and hydrogen-bonding. The related catenanes are also prepared and their affinity for anions is investigated. The first examples of interpenetrated and interlocked architectures constructed by a single charge-assisted halogen bond are also reported. <strong>Chapter Four</strong> describes the synthesis of a 1,3-dialkyl-1,2,3-triazolium-containing threading component, whose anion binding properties are studied and compared with other threading molecules. The ability of this novel thread to form pseudorotaxanes is investigated and the preparation of the related rotaxane species is outlined. <strong>Chapter Five</strong> discusses attempts to prepare rotaxanes with improved anion binding affinities through increasing the lipophilicity of the anion binding clefts. Several novel rotaxanes are described and their anion binding properties are probed. <strong>Chapter Six</strong> describes the experimental procedures used in this work and the characterisation of compounds presented in chapters two to five. <strong>Chapter Seven</strong> summarises the conclusions of this thesis.

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