A hydrogen-bonded dimer of a novel Co(II) complex of monoethanolamine with thiocyanate: synthesis, spectra, thermal behaviour and crystal structure

Abstract

A strongly hydrogen-bonded dimer of the Co(II) complex of monoethanolamine, [Co(meaH)(3)][Co(mea)(meaH)(2)](SCN)(3), was synthesized and characterized by single crystal X-ray diffractometry, UV-Vis and IR spectroscopy. The complex consists of [Co(meaH)(3)](2+) and [Co(mea)(meaH)(2)](+), and three SCN- anions. In each cation, the Co(II) ion is coordinated by a distorted octahedral arrangement of three monoethanolamine ligands in a bidentate manner. One of the monoethanolamine ligands in the [Co(mea)(meaH)(2)](+) cation is in the deprotonated form by losing its hydroxyl hydrogen. The complex cation units are held together by three strong O-H...O bonds formed between three ethanolic oxygens forming a hydrogen-bonded dimer of [Co(meaH)(3)](2+)...[Co(mea)(meaH)(2)](+). The hydrogen bonding O...O distances are significantly short at ca. 2.41(4) Angstrom. The SCN- anions are involved in hydrogen bonding connecting the dimeric units to give a three dimensional infinite network. During the thermal decomposition process, the complex loses the monoethanolamine ligands in the first stage, followed by the decomposition of the SCN- anions at higher temperatures to give metallic cobalt as the end product. (C) 2002 Elsevier Science B.V. All rights reserved.