Solvation of vanadyl acetylacetonate: a correlation between the solvent parameter ET, the electron spin resonance spectral parameters, and the optical spectra

Abstract

A good correlation between the solvent parameter E_T and the g- and A-values of vanadyl acetylacetonate in 41 solvents is reported. From the changes in the optical spectra of the complex, it is shown that the third transition (24,600–25,600 cm.^–1) is probably a charge-transfer transition (e_π→b₂) and that adduct formation is characterised by the development of an extra, relatively intense, band in the region 23,200–24,000 cm.^–1 which overlaps the e_π→b₂ band. The particularly large influence of hydrogen-bonding solvents upon the e.s.r. parameters is interpreted in terms of hydrogen bonding to the vanadyl oxygen rather than co-ordination at the sixth position.