The Ultraviolet Absorption Spectra of Alkoxy- and Hydroxybenzils

Abstract

The ultraviolet absorption spectra of benzil and seventeen alkoxy- and hydroxybenzils have been determined. The absorption maxima and the color of series of o-, m- and p-substituted benzils in ethanol solution show regularities which are not exhibited by these compounds in the crystalline state. The absorption maxima of the substituted benzils and the correspondingly substituted benzaldehydes have been shown to lie at closely comparable wave lengths. This is consistent with the skew structure of benzil, likewise to be expected for the substituted benzils, and is an indication that the excited structures which give the major contribution to absorption are closely related to those which contribute to the absorption of the substituted benzaldehydes. © 1949, American Chemical Society. All rights reserved.