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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

Ruthenium-containing linear helicates and mesocates with tuneable p53 selective cytotoxicity in colorectal cancer cells

Allison, S.J., Cooke, D., Davidson, F.S., Elliott, P.I.P., Faulkner, R.A., Griffiths, H.B.S., Harper, O.J., Hussain, O., Owen-Lynch, P.J., Phillips, Roger M., Rice, C.R., Shepherd, S.L., Wheelhouse, Richard T. 04 June 2018 (has links)
Yes / The ligands L1 and L2 both form separable dinuclear double‐stranded helicate and mesocate complexes with RuII. In contrast to clinically approved platinates, the helicate isomer of [Ru2(L1)2]4+ was preferentially cytotoxic to isogenic cells (HCT116 p53−/−), which lack the critical tumour suppressor gene. The mesocate isomer shows the reverse selectivity, with the achiral isomer being preferentially cytotoxic towards HCT116 p53+/+. Other structurally similar RuII‐containing dinuclear complexes showed very little cytotoxic activity. This study demonstrates that alterations in ligand or isomer can have profound effects on cytotoxicity towards cancer cells of different p53 status and suggests that selectivity can be “tuned” to either genotype. In the search for compounds that can target difficult‐to‐treat tumours that lack the p53 tumour suppressor gene, [Ru2(L1)2]4+ is a promising compound for further development.
2

Hierarchische Selbstorganisation von Helicaten mit substituierten 8-Hydroxychinolinliganden

Fliege, Marcel January 2009 (has links)
Zugl.: Aachen, Techn. Hochsch., Diss., 2009
3

Homo- and heterodinuclear luminescent helicates

Osetska, Olga January 2008 (has links)
Zugl.: Aachen, Techn. Hochsch., Diss., 2008
4

Selbstorganisation von Helicaten und molekularen Tetraedern

Janser, Ingo. Unknown Date (has links) (PDF)
Techn. Hochsch., Diss., 2005--Aachen.
5

Generation of coordination architectures from dynamic covalent ligand libraries / Génération d'architectures de coordination à partir de ligands dynamiques covalents

Holub, Jan 28 September 2016 (has links)
La Chimie Dynamique Combinatoire basée sur les liaisions imines (-C=N-), avec l’aide de la chimie de coordination, donne accès à différentes types d’architectures metallosupramoléculaires et de réseaux dynamiques fonctionnels. Le travail effectué au cours de cette thèse traite de ces deux aspects. Dans un premier temps des structures de types grilles moléculaire et de type hélicate ont été synthétisés, à l’aide de métaux donnant une coordination octahédrale ou tétraédrale, et leurs propriétés dans un environnement dynamique ont été étudiées. Dans un deuxième temps des réseaux dynamiques, présentant des relations agoniste/antagoniste à travers l’échange des constituants aldéhydes et amines/hydrazines réseau, ont été étudiés. Ces systèmes permettent, à travers l’amplification d’un ou plusieurs constituants, une rééquilibration du réseau permettant l’implémentation de fonction tel que l’apprentissage et la prise de décision pour ces systèmes chimiques adaptifs. Un nouveau système, est présenté et étudié ici, permettant une redistribution stable même après le retrait du stimuli métallique (ajout/retrait d’un métal), permettant à ce système de réaliser un processing d’information : apprentissage, stockage, rappel et effacement. / Dynamic Combinatorial Chemistry of imine-based dynamic covalent bonds (-C=N-), under the governance of coordination chemistry, can lead to different metallosupramolecular architectures and responsive functional systems. In this work these two aspects have been approached. Grids and helicates architectures based on aldehydes and amines/hydrazines backbones have been synthesised, in order to probe their behaviour in a dynamic network environment, using both octahedral and tetrahedral coordinating metal cations. Dynamic systems can be also represented by dynamic networks that define agonistic and antagonistic relationships between different constituents linked through component exchange. These networks can be switched through amplification of the best fittest constituent(s) in a dynamic set, allowing to access higher level functions such as training, learning, and decision making for adaptive chemical systems. A novel multi responsive system, able to be trained for information storage, has been studied, exhibiting a stable distribution even after removal of the metal stimuli, making this system able to perform information processing operations: training, storage, recall, and erase.
6

Molecular tectonics : functionalized dipyrrins for the construction of metallo-­organic architectures / Tectonique moléculaire : ligands dipyrrines fonctionnalisés pour l'élaboration de réseaux de coordination hétérométalliques

Zhang, Fan 05 October 2017 (has links)
L’objectif de ce travail a été de développer de nouvelles approches pour la fonctionnalisation des dérivés pyrroliques mono- et bis-dipyrrines en positions 1, 5, 9, qui peuvent être utilisés comme tectons pour l’auto-assemblage avec des centres métalliques menant à la construction d’entités discrètes et / ou de réseaux moléculaires périodiques infinis. Dans une première partie, une série de nouveaux dérivés dipyrrines fonctionnalisés par des groupes de coordinants dans les positions 1 et 9 via une réaction de Knoevenagel ainsi que par une autre unité coordinante ou de solubilisation en position 5 a été préparée. La coordination de ces ligands aux cations B(III) et Zn(II) mène à la formation de dérivés luminescents du type BODIPY et de complexes homoleptiques, qui ont été utilisés comme métallatectons pour la construction de polymères de coordination hétérométalliques émissifs à l’état cristallin. Dans une deuxième partie, une stratégie de synthèse de nouvelles espèces via une post-fonctionnalisation de dérivés de 2,2'-bisdipyrrine grâce à un groupement réactif à leur périphérie, telle qu'une fonction aldéhyde, amine ou acide carboxylique, a été mise au point. D'une part, un ligand tétrapyrrolique à chaîne ouverte portant des motifs benzaldéhyde en positions méso a été utilisé pour la formation d'un hélicate fermé par des liaisons imines. D'autre part, l'introduction d'un acide p-benzoïque sur l'un ou les deux côtés du squelette 2,2'-bisdipyrrine a été utilisée pour la formation de nouveaux dérivés symétriques et dissymétriques. L'assemblage de ces nouveaux ligands avec les cations Zn(II) et Ni(II) a été particulièrement exploré. / The aim of this work was to develop new approaches for the functionalization of mono- and bis-dipyrrin derivatives at positions 1, 5, 9, which can be used as tectons for self-assembly with various metal centers for the construction of discrete entities and/or infinite periodic molecular networks. In the first part, a series of new 1,9-divinyldipyrrin derivatives functionalized by coordinating groups in positions 1 and 9 via a Knoevenagel reaction and bearing another coordinating or solubilizing unit in position 5 has been explored. The assembly of these ligands with B(III) or Zn(II) centers provide luminescent complexes, which can be used as metallatectons for the construction of heterometallic coordination polymers emissive in the solid state. In the second part, the synthetic strategy for novel species via a post-functionalization of 2,2’-bisdipyrrin derivatives featuring reactive groups at their periphery such as an aldehyde, amine or carboxylic acid moiety has been explored. On one hand, a tetrapyrrolic open-chain ligand bearing benzaldehyde units at the meso position was exploited for the preparation of a strapped helicate based on imine bond formation. On the other hand, the introduction of a p-benzoic acid on one/both side of the 2,2’-bisdipyrrin backbone has been employed for the formation of novel symmetric and dissymmetric amide-bearing derivatives. The assembly of these novel ligands with Zn(II) and Ni(II) cations has been particularly explored.
7

C<sub>2</sub>-Symmetric Pyrazole-Bridged Ligands and Their Application in Asymmetric Transition-Metal Catalysis

Böhnisch, Torben 23 July 2015 (has links)
No description available.
8

Studies in Metallosupramolecular Chemistry

Cottam, Justine Ruth Amy January 2008 (has links)
Metallosupramolecular chemistry involves the construction of nanoscale molecular assemblies by reacting metal atoms with bridging organic ligands. The metal atoms act as a type of molecular ‘glue’ binding together the organic ligands in specific orientations. Thus, appropriate combinations of metal ions and ligands lead to the controlled self-assembly of interesting one-, two- and three-dimensional molecular aggregates. This thesis details the preparation of a range of novel flexible bridging heterocyclic ligands using conventional organic synthesis, and then explores their reactions with a variety of transition metal precursors. By varying the nature of the organic ligand and the transition metal precursor, new and exciting supramolecular topologies and architectures can be formed. A total of forty-eight ligands were synthesised in this work, forty-seven of which are new compounds. The majority of the ligands synthesised were based around commercially available bisphenol cores. All forty-eight of the ligands had nitrogen heterocyclic groups as coordinating units. The ligands discussed in this thesis can be divided into three main sections. The first involves the synthesis and coordination chemistry of two-armed ligands based around the Bisphenol A, Bisphenol Z and Bisphenol AP cores. The second section describes the synthesis and coordination chemistry of the larger Bisphenol P and Bisphenol M based two-armed bridging ligands. The third section describes the synthesis and coordination chemistry of various multi-substituted ligands, including tripodal ligands based around a trisphenol core, four-armed ligands and six-armed ligands. The two-armed bisphenol based ligands proved very successful as synthons in metallosupramolecular chemistry and produced many products with a variety of different metal atoms. The complexes characterised included discrete dimeric products, coordination polymers and a number of helicates, including a dinuclear quadruply-stranded helicate. Multi-armed ligands are topical, because they have multiple coordination sites that are capable of binding and bridging multiple metal atoms. Such coordination can lead to the construction of cage-like species and complicated networks. A series of three-armed ligands based around a trisphenol core were synthesised with the intention to use these to form such species on coordination with appropriate metal salts. Indeed, one of the products of self-assembly was an interesting M₃L₂ cage. Various other multi-armed ligands were also investigated. The ligands and complexes in this thesis were characterised by a variety of structural techniques, such as ¹H NMR, ¹³C NMR, mass spectrometry, elemental analysis and X-ray crystallography when crystals were obtained. The crystal structures of twenty-seven ligands and forty-three complexes are described.

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