Banglin Chen, K. Mok, S. Ng
Mar 12, 1999
Citations
0
Influential Citations
42
Citations
Journal
Polyhedron
Abstract
Five copper(II) complexes with thiophene-2,5-dicarboxylic acid (H 2 Tda): Cu(Tda)(H 2 O)⋅(H 2 O) 2 ( 1 ), Cu(Tda)(im) 2 ⋅(H 2 O) ( 2 ), Cu(Tda)(im) 4 ( 3 ), [Cu(Tda)(py) 2 ] n ( 4 ) and [Cu(Tda)(bipy)(H 2 O)] n ⋅ n [Cu(Tda)(bipy)(H 2 O) 2 ]⋅2 n H 2 O ( 5 ) (im=imidazole, py=pyridine and bipy=2,2′-bipyridine) have been synthesised and their spectroscopic and thermal properties investigated. Three of them ( 3 , 4 and 5 ) are structurally characterised and the Cu atom is in five coordinate, distorted square pyramidal environments. The thiophene-2,5-dicarboxylate molecule is monodentate in 3 in which the molecular structure is stabilised by intermolecular hydrogen bonding involving two of the four non-coordinated nitrogen atoms of the imidazole ligands and carboxylate groups from adjacent Tda 2− . In 4 the thiophene-2,5-dicarboxylate ion is bridging tridentate and bonded to three copper atoms to form a chain polymer with alternating 16-membered ring bridged by two Tda 2− and an 8-membered ring bridged by two carboxylates. Complex 5 comprises discrete [Cu(Tda)(bipy)(H 2 O) 2 ] ( 5a ), one dimensional zig–zag chain of [Cu(Tda)(bipy)(H 2 O)] n ( 5b ) and water molecules of crystallization. The thiophene-2,5-dicarboxylate molecule is monodentate in 5a and involved in intermolecular stacking interactions with 2,2'-bipyridine rings, and bidentate in 5b to bridge [Cu(bipy)(H 2 O)] to form a one dimensional zig–zag chain.