Topochemistry. Part XXXVI. Relative yields of photodimers from mixed crystals of trans-cinnamic acids and trans-cinnamides

Abstract

The relative yields of the photodimers from mixed crystals of various acrylic acids and acrylamides have been determined as functions of the wavelength of the exciting light and of the composition of the mixed crystal. In one system the yields were also determined for various times of irradiation. The yield vs. composition data were compared with data calculated on the basis of various assumptions as to the structures of the mixed crystals and the mechanism of the reaction. The wavelength effect and the fair agreement of measured and calculated yields for different compositions show that the reaction involves one excited and one non-excited molecule, and occurs at or near the site of absorption of light. Crotonic acid and amide are considered to react only as ground state partners in the reaction.