Mononuclear and polynuclear complexes of cobalt(II) carboxylates with pyridine and other heterocyclic bases

Abstract

Adducts of cobalt(II) carboxylates with pyridine and related ligands have been prepared, their electronic spectra assigned, and their magnetic properties investigated. The complex [Co(py)₂(O₂CPh)₂](py = pyridine) behaves as a six-co-ordinate species whose electronic spectrum shows retragonal splitting; [Co(2-Mepy)(O₂CPh)₂] has the properties of a trigonal-bipyramidal five-co-ordinate high-spin complex. The green complexes [Co₂(quin)₂-(O₂CR)₄](R = Ph or C₆H₄NO₂-2; quin = quinoline) are antiferromagnetic binuclear species with square-pyramidal five-co-ordination. A slate-blue form of [Co(quin)(O₂CC₆H₄NO₂-2)₂] behaves as a slightly antiferro-magnetic polymer. The complexes [Co₃(quin)₂(O₂CR)₆](R = Ph or C₆H₄NO₂-2) contain a linear array of two trigonal-bipyramidal and one octahedral cobalt atoms and are not appreciably antiferromagnetic.