UNUSUALLY STABLE CHROMIUM(V) PERFLUOROPINACOLATE COMPLEXES

Ligand substitution of chromyl chloride with the chelating dilithium perfluoropinacolate Li2(PFP) does not afford the desired chromyl perfluoropinacolate O2Cr(PFP) as previously reported. Instead a facile reductive di-substitution of O2CrCl2 occurs to yield bis(perfluoropinacolato)oxochromate(V), OCr (PFP)2-, and its structure is established as the pyridinium-pyridine salt II by X-ray crystallography. The selective hydrolysis of II affords an unusual binuclear bis-μ-oxochromate(V) salt V, the X-ray crystal structure of which consists of unique chains of binuclear chromium(V) dianions [OCr(PFP)-μ-O]22- that are linked by aquo-lithium ion bridges. The relationship of these unusually stable oxochromate(V) salts to the previously reported simple alkali salts of OCr(PFP)2- and potassium bis(2-hydroxy-2-methyl- butyrato)oxochromate(V) is discussed. © 1990.