Crystal structure of bis(tetraethylammonium) bis[4,5-disulfanyl-1,3-dithiol-2-onato(2-)]nickelate(II) and spectroscopic and electrical properties of related oxidized complexes

Abstract

Bis(4,5-disulfanyl-1,3-dithiol-2-onato)nickelate anion complexes [Ni(C ₃ S ₄ O) ₂ ] ^2- were prepared. A single- crystal structure analysis has been performed for the bis(tetraethylammonium) salt 1: orthorhombic, space group I4(1)acd, Z = 8, a = b = 19.605(3), c = 16.217(5) Å. Full-matrix least-squares refinement based on 744 independent reflections with I > 2σ(I) yielded an R factor of 0.0651. The geometry around the nickel atom is greatly distorted from square planar, with a dihedral angle of 17.4° between the dithiolate ligand planes. Although it is essentially an insulator, with an electrical conductivity of 1.4 × 10 ^-8 S cm ^-1 measured for a single crystal at room temperature, some partially and completely oxidized nickel complexes as well as iodine-doped single crystals exhibit increased conductivities of 10 ^-3 –10 ^-2 S cm ^-1 . Electronic, IR, ESR and X-ray photoelectron spectra of these complexes are discussed.