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)<inf>3</inf>][Co(mea)(meaH)<inf>2</inf>](SCN)<inf>3</inf>, was synthesized and characterized by single crystal X-ray diffractometry, UV-Vis and IR spectroscopy. The complex consists of [Co(meaH)<inf>3</inf>]2+ and [Co(mea)(meaH)<inf>2</inf>]+, 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)<inf>2</inf>]+ 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)<inf>3</inf>]2+⋯[Co(mea) (meaH)<inf>2</inf>]+. The hydrogen bonding O⋯O distances are significantly short at ca. 2.41(4) Å. 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. © 2002 Elsevier Science B.V. All rights reserved.