Three Copper(II) Complexes of Thiophene-2,5 Acid with Dissimilar Ligands: Synthesis, IR and UV-Vis Spectra, Thermal Properties and Structural Characterizations

Abstract

Three thiophene-2,5-dicarboxylic acid (H<inf>2</inf>tdc) complexes of copper(II) with 2-aminomethylpyridine (ampy), {[Cu<inf>2</inf>(μ-tdc)<inf>2</inf>(ampy)<inf>2</inf>]·2DMF}<inf>n</inf> (1), ethylenediamine (en), trans-[Cu(H<inf>2</inf>O)<inf>2</inf>(en)<inf>2</inf>](tdc) (2) and 4-methylimidazole (4-meim), trans-[Cu(H<inf>2</inf>O)<inf>2</inf>(4-meim)<inf>4</inf>](tdc)·4H<inf>2</inf>O (3) have been synthesized and characterized by spectral (IR, UV-Vis), thermal analyses and X-ray diffraction techniques. In 1, thiophene-2,5-dicarboxylate acts as a bridging bis(bidentate) ligand through four carboxylate oxygen atoms forming a 1-D zigzag polymeric chain, whereas in 2 and 3 the tdc dianion behaves as a counter ion. In all cases, the Cu(II) centers have an octahedral coordination geometry. Three-dimensional frameworks are constructed though hydrogen bonding and/or C-H···π interactions in the three complexes. © 2009 Elsevier Ltd. All rights reserved.