Cheves Walling

Phosphorescence of Adsorbed Ionic Organic Molecules at Room Temperature

Many salts of polynuclear carboxylic acids, phenols, amines, and sulfonic acids adsorbed on paper, silica, alumina, and other substrates exhibit strong triplet phosphorescence at room temperature, with no evidence of quenching by oxygen. No phosphorescence has been observed with nonionic materials. The spectra are similar to those of frozen solutions at -196�C, and the technique provides a simple means of demonstrating phosphorescence phenomena, identifying unknown materials, and investigating the spectra of triplet states.

Some properties of radical reactions important in synthesis

Abstract Properties of radical chain reactions are reviewed including propagating steps, lifetimes of chains, and choices of initiators. Structure and reactivity relations in chain-propagation steps and their effects on regio- and stereochemistry are discussed. The utility of redox chains involving transition metal ions is considered along with the importance of radical ions as reaction intermediates.

The decomposition of substituted benzoyl peroxides in the presence of dimethoxybenzenes

Abstract Benzoyl peroxides, particularly those containing electron withdrawing substituents, undergo rapid decomposition in the presence of m-dimethoxybenzene, p-dimethoxybenzene, 2,5-di-t-butyl-1,4-dimethoxybenzene, and 2,5-dimethyl-1,4-dimethoxybenzene. Reactions are first order in peroxide and dimethoxy benzene, increasing in the order given. Identified products are the acids corresponding to the peroxide and esters involving ring substitution, ring-substitution with elimination of a t-Bu group, and benzylic substitution. It is proposed that reaction involves a rate-determining charge transfer transition state leading to radical ion pairs which collapse to products. No free radicals have been detected.