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-dicyanobenzene-1,2-dithiol (3) is reported. This compound was used to prepare tetrabutylammonium salts of novel nickel complexes; the nickel(II) salt (nBu4N)2[Ni(dcbdt)2] (4), the nickel(III) salt (nBu4N)2[Ni(dcbdt)2]2 (5), and the partially oxidized NiIII/IV salt (nBu4N)2[Ni(dcbdt)2]5 (6). (dcbdt = 4,5-dicyanobenzene-1,2-dithiolate). The NiII complex presents a square-planar coordination geometry and is diamagnetic, while in the paramagnetic NiIII complex the Ni(dcbdt)2 units are strongly dimerized with the metal atom in a square-pyramidal coordination geometry and its magnetic susceptibility follows a singlet-triplet model with an antiferromagnetic coupling J = 897 K. The partially oxidized NiIII/IV complex 6 presents a weakly temperature-dependent paramagnetism of 5−6·10−4 emu/mol and a room-temperature electrical conductivity of 0.15 S/cm following a semiconducting regime.