Cobalt(II) complexes of 2-methanol-, 2,6-dimethanol- and 2-ethanolpyridines: syntheses, spectroscopic, thermal and structural characterizations of [Co-2(mu-Cl)(2)(mpy)(4)]Cl-2 center dot 2H(2)O, [Co(dmpy)(2)]Cl-2 and [Co(Cl)(4)](Hpyet)(2) (mpy=2-methanolpyridine; dmpy=2,6-dimethanolpyridine and Hpyet=2-ethanolpyridinium)

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)(2)(H2O)(4)](.)2H(2)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-2(mu-Cl)(2)(mpy)(4)]Cl(2)(.)2H(2)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)(2)]Cl-2, dmpy exhibits a tripodal chelating coordination mode through the N and two hydroxyl O atoms forming a CoN2O4 chromophore. The protonated 2-ethanolpyridinium cation Hpyet serves as a non-coordinating, but hydrogen bonded counter ion in [Co(Cl)(4)](Hpyet)(2). Based on the molecular structures, the electronic, IR spectra and thermal behavior of the complexes are discussed. 16 (C) 2003 Elsevier Ltd. All rights reserved.