Synthesis, structural, magnetic and thermal studies of copper(II) 5,5-diethylbarbiturate complexes with nicotinamide, 2,2'-bipyridine and triethanolamine

Abstract

Three new copper(II) 5,5-diethylbarbiturate (barb) complexes of nicotinamide (nia), 2,2'-bipyridine (bpy) and triethanolamine (tea), trans-[Cu(barb)(2)(nia)(2)]center dot 2H(2)O (1), cis-[Cu(barb)2(bpy)]center dot 3H(2)O (2) and [Cu-2(barb)(2)(tea)(2)]center dot 2H(2)O (3), were synthesized and characterized by elemental analysis, spectroscopic (UV-Vis and FTIR) and magnetic moment measurements. Single crystal X-ray crystallographic measurements showed that 1 and 2 are mononuclear, while 3 is binuclear, in which two copper centers were bridged by deproto-nated ethanol groups of two tea ligands. The barb ligand in these complexes is a bidentate N, O-donor. Thermal analysis (TG/DTA) studies in air indicated that the complexes first dehydrated and then the decomposition of nia, bpy or tea ligands occurred. The last exothermic stage was associated with degradation of the barb moiety to yield CuO as the end product.