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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

Molecular Networks Created by Charge-Assisted Hydrogen Bonds Between Bis(aminidinium) Cations and Carboxylates, Sulfonates, Phosphonates and Phosphates

Lie Chin Cheong, Sharon 06 1900 (has links)
L'objectif de cette étude est d'apprendre à créer de nouveaux matériaux moléculaires par design. À l'heure actuelle, il n'existe aucune méthode générale pour la prédiction des structures et des propriétés, mais des progrès importants ont été accomplis, en particulier dans la fabrication de matériaux moléculaires ordonnés tels que des cristaux. En ces matériaux, l'organisation peut être contrôlée efficacement par la stratégie de la tectonique moléculaire. Cette approche utilise des molécules appelées “tectons”, qui peuvent s’associer de manière dirigée par des interactions non covalentes prévisibles. De cette façon, la position de chaque molécule par rapport à ses voisins peut être programmée avec un degré élevé de fiabilité pour créer des cristaux et d'autres matériaux organisés avec des caractéristiques et des propriétés structurelles souhaitables. Le travail que nous allons décrire est axé sur l'utilisation de l'association des cations bis(aminidinium) avec des carboxylates, sulfonates, phosphonates et phosphates, afin de créer des réseaux moléculaires prévisibles. Ces réseaux promettent d'être particulièrement robuste, car ils sont maintenus ensemble par de multiples liaisons hydrogène assistées par des interactions électrostatiques. / The goal of this study is to learn how to create new molecular materials by design. At present, there is no general method for predicting structures and properties, but significant progress is being made, particularly in making ordered molecular materials such as crystals. In such materials, organization can be controlled effectively by the strategy of molecular tectonics. This approach uses molecules called “tectons”, which can associate in ways directed by predictable non-covalent interactions. In this way, the position of each molecule relative to its neighbors can be programmed with a high degree of reliability to create crystals and other ordered materials with desirable structural features and properties. The work that we will describe focuses on using the association of bis(aminidinium) cations with carboxylates, sulfonates, and phosphates to create predictable molecular networks. Such networks promise to be unusually robust because they are held together by multiple charge-assisted hydrogen bonds.
2

Molecular Networks Created by Charge-Assisted Hydrogen Bonds Between Bis(aminidinium) Cations and Carboxylates, Sulfonates, Phosphonates and Phosphates

Lie Chin Cheong, Sharon 06 1900 (has links)
L'objectif de cette étude est d'apprendre à créer de nouveaux matériaux moléculaires par design. À l'heure actuelle, il n'existe aucune méthode générale pour la prédiction des structures et des propriétés, mais des progrès importants ont été accomplis, en particulier dans la fabrication de matériaux moléculaires ordonnés tels que des cristaux. En ces matériaux, l'organisation peut être contrôlée efficacement par la stratégie de la tectonique moléculaire. Cette approche utilise des molécules appelées “tectons”, qui peuvent s’associer de manière dirigée par des interactions non covalentes prévisibles. De cette façon, la position de chaque molécule par rapport à ses voisins peut être programmée avec un degré élevé de fiabilité pour créer des cristaux et d'autres matériaux organisés avec des caractéristiques et des propriétés structurelles souhaitables. Le travail que nous allons décrire est axé sur l'utilisation de l'association des cations bis(aminidinium) avec des carboxylates, sulfonates, phosphonates et phosphates, afin de créer des réseaux moléculaires prévisibles. Ces réseaux promettent d'être particulièrement robuste, car ils sont maintenus ensemble par de multiples liaisons hydrogène assistées par des interactions électrostatiques. / The goal of this study is to learn how to create new molecular materials by design. At present, there is no general method for predicting structures and properties, but significant progress is being made, particularly in making ordered molecular materials such as crystals. In such materials, organization can be controlled effectively by the strategy of molecular tectonics. This approach uses molecules called “tectons”, which can associate in ways directed by predictable non-covalent interactions. In this way, the position of each molecule relative to its neighbors can be programmed with a high degree of reliability to create crystals and other ordered materials with desirable structural features and properties. The work that we will describe focuses on using the association of bis(aminidinium) cations with carboxylates, sulfonates, and phosphates to create predictable molecular networks. Such networks promise to be unusually robust because they are held together by multiple charge-assisted hydrogen bonds.
3

Linear und tetragonal strukturierte Tektone mit peripheren Aminosäure- und Peptidhaftgruppen

Eißmann, Frank 10 October 2011 (has links) (PDF)
Im Rahmen der vorliegenden Arbeit gelang die Synthese einer Reihe von neuartigen linear oder tetragonal präorganisierten tektonischen Verbindungen mit peripheren Haftgruppen, bestehend aus den natürlich vorkommenden Aminosäuren Glycin und L-Alanin oder kurzen Peptiden. Neben der Synthese stand die strukturelle Charakterisierung der Zielsubstanzen und Vorstufen im Vordergrund, wobei die Aufklärung der Kristallstrukturen einer Zielverbindung und elf relevanter Vorstufen gelang, deren Packungsstrukturen überwiegend durch N–H•••O-Interaktionen determiniert sind. Ergänzend konnten Informationen bezüglich der von den Haftgruppen gebildeten Strukturmotive im Festkörper mittels FT-IR-Spektroskopie abgeleitet werden. Die Auswertung konformationssensitiver 1H- und 13C-NMR-Signale zeigt, dass Aminosäurereste innerhalb identischer Haftgruppen in Lösung jeweils in derselben Konformation vorliegen. Fluoreszenzspektroskopische Untersuchungen der hergestellten Zielverbindungen lassen interessante Anwendungen auf dem Gebiet der Sensorik erwarten.
4

Linear und tetragonal strukturierte Tektone mit peripheren Aminosäure- und Peptidhaftgruppen

Eißmann, Frank 02 September 2011 (has links)
Im Rahmen der vorliegenden Arbeit gelang die Synthese einer Reihe von neuartigen linear oder tetragonal präorganisierten tektonischen Verbindungen mit peripheren Haftgruppen, bestehend aus den natürlich vorkommenden Aminosäuren Glycin und L-Alanin oder kurzen Peptiden. Neben der Synthese stand die strukturelle Charakterisierung der Zielsubstanzen und Vorstufen im Vordergrund, wobei die Aufklärung der Kristallstrukturen einer Zielverbindung und elf relevanter Vorstufen gelang, deren Packungsstrukturen überwiegend durch N–H•••O-Interaktionen determiniert sind. Ergänzend konnten Informationen bezüglich der von den Haftgruppen gebildeten Strukturmotive im Festkörper mittels FT-IR-Spektroskopie abgeleitet werden. Die Auswertung konformationssensitiver 1H- und 13C-NMR-Signale zeigt, dass Aminosäurereste innerhalb identischer Haftgruppen in Lösung jeweils in derselben Konformation vorliegen. Fluoreszenzspektroskopische Untersuchungen der hergestellten Zielverbindungen lassen interessante Anwendungen auf dem Gebiet der Sensorik erwarten.
5

Síntese e cristaloquímica de complexos de Hg(II) e Ni(II) com o ligante 3-(2-fluorofenil)-1-(4-acetilfenil)triazenido e atividade biológica de triazenos livres / Synthesis and crystalchemistry of Hg(II) and Ni(II) complexes with 3-(2-fluorophenil)-1-(4-acetilphenil)triazenide ligand and biological activity of free triazenes

Giglio, Vinícius Feltrin 26 July 2006 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this dissertation were synthesized six compounds, of the which four are free triazene ligands and two are triazenido complex of Hg(II) and Ni(II). The compouns were characterized by melting point, infrared an UV/VIS spectroscopy, ray-X diffraction in single crystals. They were also made analyses of biological activity of the free ligands, where the potential bacteriostatic and bactericidal and of DNA cleavage plasmidial was tested. The compound 1 crystallizes in the triclinic crystal system, space group P(-1), with cell parameters a = 8,033(4) Å, b = 8,039(5) Å, c = 10,022(6) Å, α = 93,77(2)°, β = 96,86(2)°, γ = 97,98(2)°; Z=2; The final crystal structure refinement converged to the indices of disagreement R1 = 0,0741, wR2 = 0,2547. In the solid state compond 1 reveals one-dimensional infinite chains with the base vector [100] as result of intermolecular N−H···O classic hydrogen bonds. The compound 5 crystallizes in the monoclinic crystal system, space group C2/c, with cell parameters a = 21,455(5) Å, b = 5,538(10) Å, c = 23,228(10) Å, α =γ = 90°, β = 116,301(10)°; Z=4; The final crystal structure refinement converged to the indices of disagreement R1 = 0,0220, wR2 = 0,0799. The crystal structure of 5 reveals one-dimensional infinite chains along the [010] direction through Hg−η2, η2−arene π−interactions. These one-dimensional chains can be extended to the bi-dimensional (2D) through no-classic hydrogen interactions C - H···O along the crystallographic vector [100]. The compound 6 crystallizes in the ortorrombic crystal system, space group Pbcn. with cell parameters a = 16,3394(11) Å, b = 11,9953(8) Å, c = 17,6042(12) Å, α=β=γ=90°; Z=4; The final crystal structure refinement converged to the indices of disagreement R1 = 0,0466, wR2 = 0,0948. The mononuclear complex with Ni(II) showing a rhombic distorted coordination geometry. In the solid state complex 6 reveals one-dimensional infinite chains with the base vector [010] as result of intermolecular C−H···O no classic hydrogen bonds. The biological activity results show that for compound 3 a bacteriostatic action for the Micrococcus spp, Rhodococcus spp e Staphylococcus saprophyticus in the concentration 128 μg/mL. The compound 4 show bacteriostatic action only for the cell lines ATCC Staphylococcus aureus in the concentration 128 μg/mL. The compounds 2 e 4 didn't show effectiveness for cleavage of the plasmid of DNA. / Sintetizou-se o ligante 1-(2-fluorfenil)-3-(4-acetilfenil)triazeno (1) e a partir deste os complexos [HgII(C14H11N3OF)2] (5) e cis-NiII(C14H11N3OF)2(py)2 (6), com o propósito de observar a geometria de coordenação, interações intermoleculares e o arranjo cristalino destes compostos. Sintetizou-se também os ligantes 1-(fenil)-3-(4-acetilfenil)triazeno (2), bis-1,3(4- acetilfenil)triazeno (3) e bis-1,3(4-acetiloxima)triazeno (4) a fim de se investigar o potencial bacteriostático e de clivagem do DNA palsmidial pUC18. Os compostos 1, 2, 3 e 4 foram sintetizados a partir de uma reação de diazotação via nitrito de sódio de uma amina com posterior acoplamento da mesma ou de outra amina diferente gerando compostos triazenos simétricos e assimétricos, respectivamente. O composto 5 foi sintetizado a partir da reação entre o composto 1 desprotonado e acetato de mercúrio(II) em solução de tetraidrofurano na proporção de 2:1. O composto 6 foi sintetizado a partir da reação entre o composto 1 desprotonado e cloreto de níquel(II) hexahidratado em solução metanólica na proporção 2:1. Os compostos foram caracterizados por ponto de fusão, espectroscopia na região do ultravioleta-visível e inframermelho. Somente os compostos 1, 5, e 6 foram caracterizados por difração de raios-X em monocristal. O composto 1 cristaliza no sistema cristalino triclínico, grupo espacial P(-1). O refinamento da estrutura inclui os parâmetros principais: 2684 reflexões totais; 1885 reflexões independentes; a = 8,033(4) Å, b = 8,039(5) Å, c = 10,022(6) Å, α = 93,77(2)°, β = 96,86(2)°, γ = 97,98(2)°; Z=2; refinamento com matriz completa para F2 e parâmetros térmicos anisotrópicos para átomos não hidrogenóides, obtendo-se índices finais R1 = 0,0741, wR2 = 0,2547. As moléculas do composto 1 associam-se através de ligações de hidrogênio clássicas entre N H ··· O, formando um arranjo supramolecular unidimensional na direção cristalográfica [100]. O composto 5 cristaliza no sistema cristalino monoclínico, grupo espacial C2/c. O refinamento da estrutura inclui os parâmetros principais: 11325 reflexões totais; 2311 8 reflexões independentes; a = 21,455(5) Å, b = 5,538(10) Å, c = 23,228(10) Å, α =γ = 90°, β = 116,301(10)°; Z=4; refinamento com matriz completa para F2 e parâmetros térmicos anisotrópicos para átomos não hidrogenóides, obtendo-se índices finais R1 = 0,0220, wR2 = 0,0799. As moléculas do composto 5 associam-se através de interações Hg-areno-η2,η2 π entre o íon Hg(II) e os átomos de carbono dos anéis periféricos dos dois complexos vizinhos, formando um arranjo supramolecular unidimensional na direção cristalográfica [010]. As redes unidimencionais do [HgII(RPhNNNPhR´)2]n [R = CH3C(O), R´= F] podem ser estendidas à bidimencionais (2D) através de ligações de hidrogênio não-clássicas entre C H···O ao longo da direção cristalográfica [100]. O composto 6 cristaliza no sistema cristalino ortorrômbico, grupo espacial Pbcn. O refinamento da estrutura inclui os parâmetros principais: 16030 reflexões totais; 3214 reflexões independentes; a = 16,3394(11) Å, b = 11,9953(8) Å, c = 17,6042(12) Å, α=β=γ=90°; Z=4; refinamento com matriz completa para F2 e parâmetros térmicos anisotrópicos para átomos não hidrogenóides, obtendo-se índices finais R1 = 0,0466, wR2 = 0,0948. A geometria de coordenação do composto 6 é octaédrica com distorção rômbica ao centro metálico. As moléculas do composto 6 apresenta também ligações de hidrogênio nãoclássica entre C H···O, formando um arranjo supramolecular unidimensional na direção cristalográfica [010]. Os resultados da atividade biológica mostram que o composto 3 apresenta para as bactérias Micrococcus spp, Rhodococcus spp e Staphylococcus saprophyticus ação bacteriostática para a concentração de 128 μg/mL. O composto 4 apresentou atividade bacteriostática somente para a cepa ATCC Staphylococcus aureuS na concentração de 128 μg/mL. Os compostos 2 e 4 não mostraram eficácia para clivagem do DNA plasmidial.

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