Variation of cis/trans configuration of 3,8-dithiophen and 3,8-di-3-methylthiophen-substituted 1,10-phenanthroline in their cadmium(II) nitrate complexes originating from substituent and anionic effects
作者:Bin Hu、Qian-Qian Liu、Tao Tao、Kun Zhang、Jiao Geng、Wei Huang
DOI:10.1016/j.ica.2012.09.029
日期:2013.1
A pair of 3,8-dithiophen (dtphen) and 3,8-di-3-methylthiophen (dmtphen) substituted 1,10-phenanthroline cadmium(II) nitrates, formulated as [Cd(dmtphen)(2)(NO3)(2)] (1) and [Cd(dtphen)(2)(NO3)(2)] (2), exhibit cis and trans configuration in the whole complexes because of the substituent effects of methyl group in the dmtphen ligand. In 1 and 2, both ligands possess similar cis/trans configuration but different dihedral angles from 19.0(1)degrees to 45.5(1)degrees in 1 and 2.6(1)degrees to 5.9(1)degrees in 2 due to the spatial crowding effects of methyl group. Additionally, anionic effects of NO3 , Cl , and Br have been studied where two cis Cd(II) complexes formulated as [CdBr2(dmtphen)(2)] (3) and [CdCl2(dtphen)] (4) are obtained and the side thiophene and methyl-thiophene rings in each ligand adopt the cis/trans and trans/trans configuration relative to the central phen unit. (C) 2012 Elsevier B. V. All rights reserved.