Low-temperature Spectroelectrochemistry of Tetraethylammonium Tris(ethylxanthato)nickelate(II) and Bis(ethylxanthato)nickel(II) Complexes

One-electron constant potential electrolysis of tetraethylammonium tris(ethylxanthato)nickelate(II), (NEt 4 )[Ni(S 2 COEt) 3 ] and bis(ethylxanthato)nickel(II), Ni(S 2 COEt) 2 , at their lowest oxidation peak potentials, were followed by in situ UV-VIS spectrophotometry, in acetonitrile at 253 K. In both cases [Ni III (S 2 COEt) 3 ] complex formed and detected by its electronic absorption and EPR spectra. [Ni III (S 2 COEt) 3 ] slowly disproportionated to Ni(S 2 COEt) 2 and the dimer of the oxidized ethylxanthate ligand, (S 2 COEt) 2 , with a second-order rate law.