Synthesis and spectroscopic studies of cobalt(II) complexes of thiosemicarbazone and heterocyclic bases

Co(II) complexes containing salicylaldeilyde N(4)cyclohexylthiosemicarbazon e and hererocyclic bases have been synthesised and characterized by element al anal! ses and electronic, TR and EPR spectral measurements. EPR studies of low-spin Co(II) complexes indicate the presence of an unpaired electron in the d(z)(2) orbital. It is found that the thiosemicarbazone is coordinat ed to Co(II) ions as an O-N-S tridentate ligand and the fourth(anti fifth) coordination site(s) is tare) occupied by N atom(s) of the heterocyclic bas e The magnetic and spectroscopic data indicate a square-planar structure fo r the four-coordinate and a square-pyramidal structure for the five-coordin ate complexes.