Synthesis and structural studies of novel Co(III) ternary complexes containing N(4)-substituted thiosemicarbazones of 2-hydroxyacetophenone and heterocyclic bases

An interesting series of eight neutral ternary Co(III) complexes of 2-hydroxyacetophenone N(4)-substituted thiosemicarbazones (H2L), bidentate heterocyclic bases 2,2′-bipyridine (bipy)/1,10-phenanthroline (phen) and azide with a general formula [MLB(N3)] were prepared. The complexes were characterized by means of spectroscopic methods. The coordination geometry around Co(III) in all the complexes is distorted octahedral with one dibasic tridentate ligand L2−, one bidentate heterocyclic base and one terminally coordinated azide group. Crystal structure of the compound CoL4bipyN3 was completely solved. All the electronic transitions were assigned. All complexes were diamagnetic indicating cobalt in a d6 strong field. [Copyright &y& Elsevier]