COMPLEXES OF N(4)-CYCLOHEXYLSEMICARBAZONES AND N(4)-CYCLOHEXYLTHIOSEMICARBAZONES DERIVED FROM 2-FORMYLPYRIDINE, 2-ACETYLPYRIDINE AND 2-BENZOYLPYRIDINE

2-Formyl-, 2-acetyl- and 2-benzoylpyridine N(4)-cyclohexylsemicarbazon e and N(4)- cyclohexylthiosemicarbazone complexes of cobalt(II, III), nickel(II) and copper(II) have been prepared and characterized by mola r conductivities, magnetic susceptibilities and spectroscopic techniqu es. For many of the complexes, coordination is by the neutral ligand, the main exceptions being the cobalt(III) complexes of the three thios emicarbazones and three of the benzoylpyridine derivatives. Thus, bond ing is via the pyridyl nitrogen, azomethine nitrogen and thione/thiola to sulfur. The five-coordinate copper(II) complex of 2-acetylpyridine N(4)-cyclohexylthiosemicarbazone, [Cu(HAc4CHex)Cl-2], approaches squar e pyramidal stereochemistry with the basal Cu-Cl bond significantly sh orter than the apical Cu-Cu bond.