Cobalt(II) Complexes of 2-Methanol 2,6-Dimethanol and 2-Ethanolpyridines

Abstract

Cobalt(II) complexes of 2-methanol-, 2,6-dimethanol- and 2-ethanolpyridines have been prepared by the reaction of the corresponding protonated substituted pyridines with [Co(sac)<inf>2</inf>(H<inf>2</inf>O) <inf>4</inf>]·2H<inf>2</inf>O, where sac is saccharinate, and characterised by elemental analyses, IR, UV-Vis, magnetic measurements and single crystal X-ray diffraction. The corresponding 2-methanolpyridine (mpy) complex [Co<inf>2</inf>(μ-Cl)<inf>2</inf>(mpy)<inf>4</inf>]Cl <inf>2</inf>·2H<inf>2</inf>O is dimeric with chloro bridges and each cobalt(II) ion has an octahedral coordination with two chloro and two bidentate (N,O) ligands. In the 2,6-dimethanolpyridine (dmpy) complex [Co(dmpy) <inf>2</inf>]Cl<inf>2</inf>, dmpy exhibits a tripodal chelating coordination mode through the N and two hydroxyl O atoms forming a CoN<inf>2</inf>O <inf>4</inf> chromophore. The protonated 2-ethanolpyridinium cation Hpyet serves as a non-coordinating, but hydrogen bonded counter ion in [Co(Cl) <inf>4</inf>](Hpyet)<inf>2</inf>. Based on the molecular structures, the electronic, IR spectra and thermal behavior of the complexes are discussed. © 2003 Elsevier Ltd. All rights reserved.