The ultraviolet photochemistry of derivatives of triphenylmethane. Part I. Measurement of the rate constants in the photolysis of triphenylmethyl halides

Abstract

The ultraviolet photolysis of dilute solutions of Ph₃C–X, (where X = H, F, Cl, Br, or l) in cyclohexane in the absence of oxygen has been investigated. The results can be explained by a mechanism which involves the triphenylmethyl free radical in an excited electronic state. This is formed by dissociation of triplet Ph₃C–X, formed by intersystem crossing from the lowest excited singlet state. The rate constants for several of the primary photochemical processes involved have been measured and the effect of changing X is discussed.