Chromium corroles in four oxidation States.

We have isolated and characterized chromium complexes of 5,10,15-tris(pentafluorophenyl)corrole [(tpfc)H(3)] (1) in four oxidation states: [(tpfc(*))CrO][SbCl(6)] (6); [(tpfc)CrO] (2); [(tpfc)CrO][Cp(2)Co] (4); and [(tpfc)Cr(py)(2)] (3). Complex 6 was prepared both by electrochemical and chemical oxidation of 2; its formulation as a Cr(V)O ligand-radical species is based on UV-visible absorption as well as EPR measurements. Cobaltocene reduction of 2 gave 4; it was identified as a diamagnetic d(2) Cr(IV)O complex from its sharp (1)H NMR spectrum. Reaction of 2 with triphenylphosphine yielded a chromium(III) corrole, [(tpfc)Cr(OPPh(3))(2)] (5). Owing to its air sensitivity, 5 could not be isolated in the absence of excess OPPh(3). The structure of the Cr(III) bis-pyridine complex (3) was determined by X-ray crystallography (Cr-N distances: 1.926-1.952 A, pyrrole; 2.109, 2.129 A, pyridine).