Solvent—Solute interaction. Solvation of vanadyl acetyl-acetonate in non-aqueous media

The electronic absorption spectrum of vanadyl acetylacetonate has been studied in 15 organic solvents. It has been found that wavenumbers and molar absorptivities of the long-wavelength bands (d-d transitions) can be well described by a complementaryLewis acid—base model includingGutmann's donor number [Gutmann V., Wychera E., Inorg. Nucl. Chem. Letters2, 257 (1966)] and acceptor number [Mayer U., Gutmann V., Gerger W., Monatsh. Chem.106, 1235 (1975)] of a solvent. This model describes also the solvent effect of the hyperfine splitting constant,A _iso (⁵¹V), from e.s.r. spectra of VOacac ₂. These observations are discussed in terms of the donor—acceptor concept for solvent—solute interactions.