An investigation of the stability and reactivity of a variety of radical species generated from azo compounds will be conducted. Reaction mechanisms will be established by the use of a variety of techniques including electroanalytical methods, laser flash photolysis, calorimetry, preparative and quantitative photochemistry, and ESR. The projects to be investigated will include: (1) assessment of the stability of azaallyl radicals and the factors which determine their recombination to yield dimers; (2) determination of the lifetimes of cyclic biradicals using a free radical clock; and (3) elucidation of the detained mechanism of the oxidation of azoalkanes by stable cation radical salts. The project will involve both the synthesis of a variety of novel azo compouunds as well as precise calculations of rate processes and the determination of the identity of reactive intermediates. %%% This grant from the Organic Dynamics Program supports the continuing work of Professor Paul S. Engel at Rice University. These studies will be center around the reactions and inherent stabilities of radical species which are generated upon exposure of certain chemical compounds to either heat or light. In order to ascertain the nature of these radical species, which exist for only a few billionths of a second, a variety of sophisticated methods will be utilized. By understanding the stability of these intermediate compounds, it will be possible to devise similar systems that will be more efficient and result in faster reactions. This is particularly important since the base compounds to be investigated represent a class of chemical substances which have found widespread use in a variety of industrial applications involving the processing of plastics and foams.
