Mercury (II) benzisothiazolinate (bit) complexes with diamine or phosphine co-ligands, and subsequent conversion to 2-mercaptobenzamide complexes. Crystal structures of [Hg(bit)2(L2)], L2 = bipyridine or phenanthroline

Abstract

Reaction of mercury(II) acetate [Hg(Ac)2] or mercury(II) chloride [HgCl2] with two moles equivalent of Na[bit] (bit = benzisothiozolinate) afforded [Hg(bit)2] as white solid in 96 and 70% yield respectively. Treatment of [Hg(bit)2] with the bidentate ligands; 2,2-bipyridine (bipy), 1, 10-phenanthroline (phen) or ethylene diamine (en) in absolute ethanol afforded the complexes; [Hg(bit)2(bipy)], [Hg(bit)2(phen)] or [Hg(bit)2(en)] as white solids in 82–88% yields. The crystal structures of [Hg(bit)2(bipy)] and [Hg(bit)2(phen)] were determined, each showing a distorted tetrahedral geometry around mercury with the two benzisothiazolinate (bit) ligands being coordinated via nitrogen atom and lying almost perpendicular to each other. Reactions of [Hg(bit)2] with two moles equivalent of Ph3P in absolute EtOH at room temperature or one mole equivalent of 1,3-is(diphenylphosphino)propane (dppp) in boiling CHCl3, afford [Hg(bit)2(Ph3P)2] and a (2:1) mixture of [Hg(bit)2(κ2-dppp)] and [Hg(bit)2(μ2-dppp)]n. Treatment of [Hg(bit)2] with bis(diphenylphosphino)methane (dppm), afford [Hg(mbm)2] (Hmbm = 2-mercaptobenzamide), while treatment with bis(diphenylphosphino)butane afford [Hg(mbm)2(dppb)]. A sulfur-nitrogen bond breaking within the heterocyclic ring of the bit ligand took place followed by protonation of the nitrogen atom to afford the final product.