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TY - THES AU - Schmid, Sören TI - Lumineszierende zweikernig dreisträngige Helicate CY - Aachen PB - Publikationsserver der RWTH Aachen University M1 - RWTH-CONV-121798 SP - 154 S. : Ill.,graph. Darst. PY - 2005 N1 - Aachen, Techn. Hochsch., Diss., 2005 AB - Luminescent triple-stranded dinuclear helicates The building of systems showing a special function or a property that makes them suitable for the preparation of functional materials will become more and more important in the next years. Based on the "bottom-up approach" supramolecular chemistry can play an important part on this field. This work deals with the building and examination of triple-stranded dinuclear helicates. By using special ligand systems and metals, it its possible to give these aggregates a special property. In the centre of the investigations is the use of lanthanoids. One of their properties is their luminescence, which makes them already suitable for the building of laser systems or colour displays. This luminescene should be enhanced by the coordination with special ligands. Also the energy transfer processes from the ligands to the metal centres will be investigated. Three different ligand systems will be prepared in this work. One of those is based on 8-hydroxyquinoline. By connecting two of these metal coordinating units, ligands will be received, which are used in the building of neutral triple-stranded dinuclear helicates. By reaction of those ligands with aluminium(III)- and gallium(III)-ions, materials can be obtained with a special luminescence property. Another ligand motif is based on ß-diketones. Connecting two ß-diketone moieties with a chiral spacer leads to a chiral ligand tetraketone ligands, which can be used in self-organizing processes with gallium(III)- and iron(III)-ions to build neutral triple stranded dinuclear helicates. The evidence, that only on enantiomer is present is given in solution by NMR-investigation and in the solid state via X-ray-analyses. Because of a cavity inside of the helicates it is possible to include in a heterogeneous reaction selectively lithium cations. This process can be seen by NMR-experiments. Based on these experiments several chiral ligands based on ß-diketones were synthesized and used in self-assembly processes with lanthanoids. Some of the resulting helicates were investigated for their luminescence. Especially the europium-, terbium- and holmium-helicates show a measurable luminescence. The different ligands showed different properties in the energy transfer from the ligands to the metal centres depending on the substituents on the ß-diketon-moyeties. It can be shown, that the presence of an aromatic system in the ligand enhances the energy transfer. Is there also a halogen at the aromatic substituent, the energy transfer will be more enhanced. In cooperation with the working group of Z. Pikramenou of the university of Birmingham, it was possible to synthesize a quadruple-stranded dinuclear helicate and to investigate this for the luminescence properties. In the last part mixed N/O-donor-systems based on picolinates are synthesized and characterized. These ligands should also be used in the formation of triple-stranded dinuclear helicates. LB - PUB:(DE-HGF)11 UR - https://publications.rwth-aachen.de/record/60068 ER -