Spectroscopic Studies of Mixed Amine Carbonyl Complexes of d6 Structure. II. Solvent Effect on the Ultraviolet and Visible Absorption Spectra of Diamine-tetracarbonyl Complexes of Chromium(0), Molybdenum(0) and Tungsten(0)

Absorption bands, especially metal to amine charge transfer bands of bipyridyl- and phenanthroline-tetracarbonyl chromium (0), molybdenum (0) and tungsten (0) are shifted in various solvents by less than 4500 cm−1. The shift is discussed in accordance with McRae’s equation, which was derived with the point-dipole approximation. The solvents can be classified into two groups, the alcohol and the ester group. When three constants corresponding to (1) the interaction between induced dipoles of the solute and of the solvent, (2) the interaction between permanent dipole of the solute and induced dipole of the solvent, and (3) the interaction between permanent dipoles of the solute and of the solvent, are duely chosen for the two groups of solvent individually, the experimental values are satisfactorily accounted for. Short range interactions, such as hydrogen bonding can be ignored.