Synthesis, structure and physical properties of tetrabutylammonium salts of nickel complexes with the new ligand dcbdt=4,5-dicyanobenzene-1,2-dithiolate, [Ni(dcbdt)(2)](z-) (z = 0.4, 1, 2)

The synthesis and characterization of the new aromatic ortho-dithiol, 4,5-d icyanobenzene-1,2-dithiol (3) is reported. This compound was used to prepar e tetrabutylammonium salts of novel nickel complexes; the nickel(II) salt ( nBu(4)N)(2)-[Ni(dcbdt)(2)] (4), the nickel(III) salt (nBu(4)N)(2)[Ni(debdt) (2)](2) (5), and the partially oxidized Ni-III/IV salt (nBu(4)N)(2)[Ni(dcbd t)(2)](5) (6). (dcbdt = 4,5-dicyanobenzene-1,2-dithiolate). The Ni-II compl ex presents a square-planar coordination geometry and is diamagnetic, while in the paramagnetic Ni-III complex the Ni(dcbdt)(2) units are strongly dim erized with the metal atom in a square-pyramidal coordination geometry and its magnetic susceptibility follows a singlet-triplet model with an antifer romagnetic coupling J = 897 K. The partially oxidized Ni-III/IV complex 6 p resents a weakly temperature-dependent paramagnetism of 5-6 . 10(-4) emu/mo l and a room-temperature electrical conductivity of 0.15 S/cm following a s emiconducting regime.