Electron spin resonance studies on some perfluoropinacolates of vanadium(IV) and chromium(V)
E.s.r. and optical spectral measurements of solutions of the perfluoropinacolate(2–)(pfp) derivatives of vanadium(IV) and chromium(V), [VO(pfp)2]2– and [CrO(pfp)2]–, in a range of solvents have been carried out. Analysis of the bonding parameters suggests strong hydrogen bonding in water between the vanadyl or chromyl oxygen atom and the solvent, with the water molecule bonded in the vertical plane which does not include the pfp ligand. There is negligible solvent interaction with the vacant sixth co-ordination position. The choice of values for the spin–orbit coupling parameter ξ and the hyperfine parameter P for use in the calculations of bonding parameters is discussed.