Sulfur K-edge X-ray absorption spectroscopy as a probe of ligand-metal bond covalency: Metal vs ligand oxidation in copper and nickel dithiolene complexes

A coalition of Cu L-edge and S K-edge X-ray absorption data and density functional theory calculations is correlated with [super 33]S electron paramagnetic resonance superhyperline results to obtain the dipole integral for the S 1s->3p transition for the dithiolene ligand maleonitriledithiolate (MNT). The conclusions are combined with the [l.sub.s] of sulfide to experimentally obtain a relation between the S 1s->4p transition energy and dipole integral over a large range of [Q.sup.S.sub.mol].