ELECTRON-TRANSFER BEHAVIOR OF OXORHENIUM(V), NITRIDORHENIUM(V) AND RHENIUM(III) DIETHYLDITHIOCARBAMATE COMPLEXES

The voltammetric behaviour of ReN(S2CN(Et)2)4, Re(S2CN(Et)2)3, ReOX(S2CN(Et)2)2, where X = Cl or Br, and Re2O3(S2CN(Et)2)4, were examined in five non-aqueous solvents. The nitridorhenium(V) complex underwent a non-reversible one-electron reduction followed by a chemical reaction. The rhenium(III) complex underwent a reversible one-electron oxidation to form the Re(IV) species; a second one-electron oxidation was followed by decomposition. The oxorhenium(V) monomers exhibit an equilibrium in solution between ReOX(S2CN(Et)2)2 and [ReO(S2CN(Et)2)]+ + X-. Reduction of the latter caused severe electrodeposition which could be observed with the naked eye; the deposited material was non-conducting. The position of the equilibrium depended strongly on the identity of X-. The potentials were strongly solvent dependent, with deposition of ReO(S2CN(Et)2)2 greatly reduced in the presence of electron-donating solvents. The anodic behaviour of Re2O3(S2CN(Et)2)4 consisted of a one-electron process which was followed rapidly by cleavage of the mu-oxo bridge to form [ReO(S2CN(Et)2)2]+ and ReO2(S2CN(Et)2)2.