Voltammetry of monomeric and dimeric oxorhenium(V) complexes of Schiff base ligands N,N'-ethylenebis(acetylacetone)diimine, N,N'-ethylene(salicylidene)diimine and N,N'-phenylenebis(salicylidene)diimine

The electrochemical study of six Schiff base complexes of oxorhenium(V) of the general formula Re(2)O(3)L(2) and ReOCIL (L = N,N'-ethylenebis(acetylacetone)diimine (acacen), N,N'-ethylene(salicylidene)diimine (salen) and N,N'-phenylenebis(salicylidene)diimine (salphen)) was undertaken. In non-aqueous media the oxorhenium(V) monomers exhibit an equilibrium in solution (between forms ReOCIL and [ReOL](+) + Cl-), the position of the equilibrium dependent on L. A one-electron reduction and one-electron oxidation are observed, followed by a fast chemical reaction, resulting in decomposition of the complex. The mu-oxo dimeric complexes underwent a two-electron reduction followed by decomposition to an electroinactive product. Successive one-electron oxidations of each rhenium in Re(2)O(3)L(2) were observed. Each electron-transfer step was coupled to a chemical reaction; the generation of [Re(2)O(3)L(2)](+) Was followed by the cleavage of the mu-oxo bond and formation of mono-ore species. This reaction was much slower than the decomposition which followed generation of [Re(2)O(3)L(2)](2+).