Bis-(5,5 '-diethylbarbiturato) copper(II) and cadmium(II) complexes with ethylenediamine. Synthesis, crystal structures, spectroscopic and thermal characterization of cis-[Cu(barb)(2)(en)] and {[Cd(barb)(2)(mu-en)]center dot 2H(2)O}(n)

Abstract

Two new bis(5.5'-diethylbarbiturato) (barb) complexes ofcopper(II) and cadmium(II) with ethylenediamine (en) were synthesized and characterized by elemental analysis, FT-IR spectroscopy and thermal analysis. In addition. their solid-state structures were determined by single crystal X-ray diffraction studies. cis-[Cu(barb)(2)(en)] (1) crystallizes in the monoclinic space group of C2(1)/c and consists of neutral monomeric units, in which the copper(II) ion exhibit a highly distorted octahedral coordination by two barb anions and a neutral chelating en ligand. The individual molecules of I are held together by N-(HO)-O-... hydrogen bonds, forming a three-dimensional network. {[Cd(barb)(2)(mu-en)]center dot 2H(2)O}(n) (2) is a one-dimensional coordination polymer and also crystallizes in the monoclinic crystal system (P2(1)/c). In 2, [Cd(barb)(2)(en)] building blocks ire connected into a chain by bridging NH2 group of en, and the individual chains are further stacked by O (HO)-O-... and N-(HO)-O-... hydrogen bonds to form a three-dimensional supramolecular framework, The barb ligands in both complexes act as a bidentate ligands via the negatively charged imino N atom and one of the carbonyl O atoms adjacent to the imino N atom The M-O bond distances in both complexes are Much longer than M-N bond distances, indicating a weak interaction of the carbonyl group of barb.