Crystal structure, spectral and electrochemical properties of [TBA](2)[Ni(i-MNT)(2)], [TBA][Ni(i-MNT)(2)], [TBA](2)[Ni(i-MNS)(2)] and related bis(1,2-dithiolene) metal complexes

The synthesis, crystal structure and physical properties of bis(1,1-dithiolene) or bis(1,1-diselenolene) metal complexes of [TBA](2)[Ni(i-MNT)(2)], [TBA][Ni(i-MNT)(2)] and [TBA](2)[Ni(i-MNS)(2)] (i-MNT=2,2-dicyanoethylene-1,l-dithiolate, i-MNS=2,2-dicyanoethylene-1,1-diselenolate) were studied and compared to one another or to tie related bis(1,2-dithiolene) metal complexes of 5,6-dihydro-1,4-dithiin-2,3-dithiolate, 1,3-dithiole-2-thione-4,5-dithiolate and 1,3-dithiole-2-one-4,5-dithiolate ligands. The structures of the complexes contain equidistant anionic stacks well separated by the counter cation sheets. The planarity and short C-S or C-Se distances in the structures indicate extensive delocalization of the pi-system in the compounds. The relative low conductivities for the complexes are due to the low polarizability,large intra- and inter-stack S ... S distances, and the relative high on-site electron-electron repulsion energy in the compounds.