SYNTHESIS OF PROTONATED CARBOXYLATO AND TRIFLUOROMETHANESULFONATO DERIVATIVES OF VANADIUM(II) BY REDOX REACTIONS ON BIS(MESITYLENE)VANADIUM(0)

Bis(mesitylene)vanadium(0), V(mes)(2), underwent a two-electron redox process in heptane with CF3SO3H affording the vanadium(II) derivative [V(CF3SO3)(2)(CF3SO3H)], an example of a co-ordination compound contai ning both the acid and its conjugated base in its composition. The van adium(0) complex and CF3CO2H gave a product resulting from a one-elect ron transfer process, namely [V(mes)(2)][CF3CO2]. This compound, which dissolves unchanged in neat CF3CO2H-(CF3CO)(2)O, evolves to the vanad ium(II) derivative [H(thf)(n)][V(CF3CO2)(3)] (thf = tetrahydrofuran) b y addition of tetrahydrofuran. Deprotonation of the vanadium(II) compl exes occurs in the presence of thf or heterocyclic nitrogen bases to f orm the ionic derivatives [HB][VA(3)], B = thf or a heterocyclic nitro gen base; A = CF3SO3 or CF3CO2. The trifluoroacetato derivative [H(thf )(n)][V(CF3CO2)(3)] undergoes methylation with CH2N2 to the vanadium(I I) ester adduct [V(CF3CO2)(2)(CF3CO2CH3)], and is oxidized to the vana dium(III) trifluoroacetato derivatives [V(CF3CO2)(3)] and [V(CF3CO2)(2 )C14H8O2] by benzoyl peroxide (or dioxygen) and 9,10-phenanthrenedione , respectively.