X-ray photoelectron spectra and electrical properties of new metal complexes of [M(DMID)2][TAA]x

X-ray photoelectron spectroscopy (XPS) spectra of a series of metal complexes of the DMID ligand [M(DMID)2][TAA]x. (DMID=1,3- dithiole-2-one-4,5-dithiolate, MNi, Cu, Zn; TAA = tetraalkylammonium, such as tetrabutylammonium (TBA), tetraethylammonium (TEA), and tetramethylammonium (TMA); X = integer or non-integer) were studied by comparing with other metal bisdithiolene complexes. The XPS results show that in the metal-DMID complexes the formal oxidation states of the central chelating metal ion are in the valence states of 3+ with the extra negative charge residing essentially on the ligands, especially on the sulfur atoms, and the electron density on the sulfur atoms is higher than that in the electron-rich organic donor molecule tetrathiafulvalene (TTF). Electrical properties of these complexes were investigated by conductivity and cyclic voltammetric measurements. Furthermore, the effects of the central metal atoms, counter cations and ligands on the electrical properties and XPS shifts are discussed.