Electrochemical confirmation that (7V,7V-ethylenebis(saiicylideneaminato))oxovanadium(IV), VO(salen), reacts with trifluoromethanesulfonic acid (CF3SO3H) or triphenylmethyl tetrafluoroborate (Ph3C(BF4)) to form a deoxygenated complex, VIV(salen)2+, and a µ-oxodinuclear complex, [(salen)VOV(salen)]X2, (X = CF3SO3™ or BF4-) is presented. Cyclic voltammograms of VO(salen) in the presence of CF3SO3H or Ph3C(BF4) exhibit reversible waves with formal potentials near 0.5 and 0.8 V (vs Ag/AgCl). The cathodic wave at 0.5 V is argued to arise from the combined reduction of V(salen)2+ and the µ-dimeric complex and the wave at 0.8 V from the oxidation of the V(salen)2+ complex. The diffusion coefficients of these three complexes in acetonitrile were determined. The dimerization of VO(salen) is initiated by deoxygenation of the V=0 center by H+ or Ph3C+ to produce V(salen)2+ which enters into an equilibrium with a second VO(salen) complex to produce the µ-dimer. The kinetics of

A catalytic amount of Lewis acids ([Lewis acid]/[Disulfide] = 1/200) facilitated electron transfer from diaryl disulfides to a stoichiometric amount of another oxidizing agent by which linear poly[thio(1,4-arylene)] was produced. Such Lewis acids as SbCl5 and FeCl3 facilitated oxidation of diphenyl disulfide by quinones more efficiently than protic acids such as CF3COOH, where the Lewis acid showed more than 200-fold more activity than the protic acid. Oxovanadium complex-catalyzed oxygen-oxidation of disulfides was also facilitated by these Lewis acids. The catalysis of these Lewis acids includes not only the activation of quinones or the oxovanadium complex, but also the lowering of the oxidation potential of the monomers.

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μ-Oxo-bis[(N,N′-ethylenebis(salicylideneaminato))vanadium(IV)] tetrafluoroborate is prepared from (N,N′-ethylenebis(salicylideneaminato)) oxovanadium(IV) (VO(salen)) through an electrophilic reaction by triphenylmethyl tetrafluoroborate (Ph3CBF4) in dichloromethane. The voltammetric analysis of the binuclear complex in dichloromethane revealed a one-step two-electron transfer at 0.58 V (vs Ag/AgCl) based on the disproportionation (2VIVOVIVIIIOVIV + VIVOVV).V

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