SYNTHESIS, CYCLIC VOLTAMMETRIC AND ELECTROSPRAY MASS-SPECTROMETRIC STUDIES OF A SERIES OF TRIS-SUBSTITUTED 1,2-DITHIOLENE COMPLEXES OF TUNGSTEN AND MOLYBDENUM

Ten new nonsymmetric dithiolenes of the general formula [RR'(C2S2)](3) M were synthesized, from the corresponding 1,3-dithiol-2-ones, or from the corresponding mixed benzoins and tetraphosphorus decasulfide. The redox properties of these ten complexes together with those of the sy mmetric ones with R = R' = Ph and M = Mo or W, were investigated by cy clic voltammetry. Two processes were only observed, assigned to C --> C1- and C1- --> C2- (C the complex), for which the quasi-reversible E( 1/2) potentials are highly dependent on the nature of the central meta l ion, and for the same metal on the nature of the ligand and on the s ubstituents on the phenyl rings. The ease by which the complexes are r educed is most likely the reason they give ESMS (negative mode) spectr a, in spite of the fact they are neutral in solution. The process of t his reduction and the parameters affecting it are investigated and dis cussed.