Structural, electronic and computational studies of heteroleptic Cu(I) complexes of 6,6¡ä-dimesityl-2,2¡ä-bipyridine with sulfur-substituted dipyridophenazine ligands

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• 作者：Michael G. Fraser ; Holly van der Salm ; Scott A. Cameron ; Jonathan E. Barnsley ; Keith C. Gordon ; ^{kgordon@chemistry.otago.ac.nz}
• 关键词：Copper(I) ; Heteroleptic ; Dipyridophenazine ; Crystal structure ; DFT ; Resonance Raman spectroscopy
• 刊名：Polyhedron
• 出版年：2013
• 出版时间：22 March, 2013
• 年：2013
• 卷：52
• 期：Complete
• 页码：623-633
• 全文大小：1132 K

文摘

A series of stable heteroleptic Cu(I) complexes of 6,6¡ä-dimesityl-2,2¡ä-bipyridine with three sulfur-substituted dipyridophenazine ligands, and unsubstituted dppz are synthesized and studied. The X-ray crystal structures of the complexes display coordinative flexibility of the Cu(I) metal ion and display strong intramolecular ¦Ð-¦Ð stacking interactions. The coordination geometries of the Cu(I) metal centers are characterized by the ¦Ó₄ parameter, and range from 0.626 for [Cu(bpy(Mes)₂)(dppz(Sdec)₂]BF₄ to 0.757 for [Cu(bpy(Mes)₂)(dppzS₂CS)]BF₄. Cyclic voltammetry reveals Cu(I)/Cu(II) oxidation potentials around 0.83 V for all the complexes studied, consistent with a similar coordination environment of the complexes in solution. The ligand-based reduction potentials are consistent with the electronic nature of the sulfur substituent. Resonance Raman spectroscopy and TD-DFT calculations reveal the presence of an MLCT ¡ú bipyridine transition with 488 and 514.5 nm excitation, and dppz-type chromophores ranging from UV (351 nm) to the visible (457 nm) excitation wavelengths. For [Cu(bpy(Mes)₂)(dppzS₂CS)]BF₄ and [Cu(bpy(Mes)₂)(dppz(Sdec)₂]BF₄ the most intense optical transition at 434 and 442 nm respectively are assigned as intraligand (IL)/MLCT transitions.