Mixed-ligand Complexes of Cobalt(III) with Dimethylglyoxime

Department ot Chemistry, lnorganic Chemistry Section, Jadavpur University, Calcutta-700 032 Manuscript received 9 February 1993, revised 17 June 1993, accepted 23 June 1993 Mixed-ligand complexes of cobalt(III) of the types [Co(SBx)(DMGH)] and [Co(SBy)(DMGH)], where SBx = dianion of tetradentate Schiff base; SBy = monoanion of bidentate Schiff base; DMGH = monoanion of dimethylglyoxime, were isolated from the reaction of alcoholic suspension of cobalt(III) dimethylglyoximate dihydrate with Schiff bases in 1 : 1 and 1 : 2 molar ratios for SBx and SHy respectively. Further mixed-ligand complexes of the types [Co(SBy)2(Lig)] and [Co(SBy)(Lig)2], where Lig = monoanion ofacetylacetone or monoanion ofsalicylaldehyde, were also obtained when preoxidised solution of cobalt(m) acetylacetonate dihydrate and cobalt(III) salicylaldehyde dihydrate were treated with bidentate Schiff bases in 1 : 2 molar ratios. Non-planar arrangement of the Schiff bases and the bidentate ligand anions occupying cis-positions around cobalt(III) ion have been suggested