Tetrahedral Zinc Complexes with Liquid Crystalline and Luminescent Properties: Interplay Between Nonconventional Molecular Shapes and Supramolecular Mesomorphic Order

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• 作者：Emma Cavero ; Santiago Uriel ; Pilar Romero ; José ; Luis Serrano ; Raquel Gimé ; nez
• 刊名：Journal of the American Chemical Society
• 出版年：2007
• 出版时间：September 19, 2007
• 年：2007
• 卷：129
• 期：37
• 页码：11608 - 11618
• 全文大小：745K
• 年卷期：v.129,no.37(September 19, 2007)
• ISSN：1520-5126

文摘

Novel metallomesogens with luminescent properties and liquid crystalline behavior at roomtemperature have been achieved by the preparation of zinc complexes with polycatenar pyrazole and bis(pyrazolyl)methane ligands. Their molecular structures do not have a conventional shape in that they arefar from the typical rod-like and flat disc-like geometries of common liquid crystals. They consist of anonplanar nucleus due to the methylene spacer and/or the coordination to the tetrahedral center, asconfirmed by single crystal analysis of the cores. The different numbers and positions of side chains in thepyrazole ligand enabled us to access lamellar and columnar mesophases and, of particular interest, toobtain columnar arrangements at room temperature. Supramolecular models for the organization of themolecules in the mesophases are proposed on the basis of the small-angle XRD diffractograms. The zinccomplexes display luminescence in the near UV-blue region with large Stokes shifts. An interplay betweennon-conventional molecular shapes (due to the tetrahedral core) and the supramolecular mesomorphicorder (due to the ligand design) led to materials that interestingly embody two rather opposite properties,a columnar self-organizational ability and luminescence with weak intermolecular interactions.