Synthesis and structural elucidation of new complexes of 2,4- and 3,5-dimethyl diphenyldithiophosphates with cobalt(II).

A new series of donor-stabilized addition complexes of cobalt(II) with disubstituted diphenyldithiophosphates [{(ArO)2PS2}2CoL2] {Ar = 2,4-(CH3)2C6H3 [(1)-(3)] and 3,5-(CH3)2C6H3 [(4)-(6)]; L = C5H5N [(1), (4)], 3,4-(CH3)2C5H3N [(2), (5)] and 4-(C2H5)C5H4N [(3), (6)]} were successfully isolated and characterized by elemental analyses, magnetic moment measurements, IR and single-crystal X-ray analysis. Complexes (3), (4) and (5) crystallize in the monoclinic space groups P2(1)/n, P2(1)/n and P2(1)/c, respectively, whereas complex (6) crystallizes in the triclinic space group P1¯. X-ray diffraction analysis of complexes (3)-(6) reveals a six-coordinated distorted octahedral geometry for the CoS4N2 chromophore defined by two chelating diphenyldithiophosphate anions as well as two N-donor ligands. Two diphenyldithiophosphate ligands are coordinated to the cobalt ion as a bidentate ligand chelating via the two thiolate S atoms. Each of them forms a four-membered chelate ring in the equatorial plane. The N atoms from two donor ligands are axially coordinated to the Co atom in a mutually trans position.