Chances and Limits of the Coordination Chemistry with Bis(benzene-l,2-dithiolato) Ligands

The incorporation of benzene-l,2-dithiolato building blocks into supramolecular coordination assemblies is the main objective of the investigations described here. Special interest is directed towards dinuclear complexes with bis(benzene-l,2-dithiolato) ligands, which might be able to form helical structures. Bis(benzene-l,2-dithiolato) ligands are accessible by ortho-functionalization and subsequent linkage of two benzene-l,2-dithiol units. The preparation of well defined complexes of titanium, cobalt and nickel with bis(benzene-l,2-dithiolato) ligands requires strictly thermodynamic equilibration conditions. In that case the size and shape of the ligand backbone determine if dinuclear double-stranded or mononuclear chelate complexes are obtained. The dinuclear double-stranded complexes with Ni(II) and Ni(III) are characterized by a coplanar non-helical arrangement of the square-planar bis(benzene-l,2-dithiolato)nickelate moieties. The complete structural characterization of the series [M(C6H4S2-1,2)3]n- (n = 0, 1, 2) for molybdenum and tungsten indicates an interesting coordination chemistry of dinuclear triple-stranded complexes.