Three research areas will be pursued: (1) New photochemical reactions that proceed by way of alkyl propargyl, alpha-acyl-substituted alkyl propargyl, or acyl propargyl biradicals will be explored. This study will include a consideration of the multiplicity of the biradical intermediates and the consequences to the course of reaction. (2) Independent preparation of carbonyl-substituted biradicals that are intermediates in intramolecular ?2+2!- photocyclization will be carried out. (3) The role of triplet energy and specific structure on the selectivity of hydrogen abstraction by heteroaromatic nitrogen triplets will be investigated. Intramolecular abstraction of primary, secondary, and tertiary nitrogen in pyridines, pyrimidines, and pyrazines will be studied. %%% This grant from the Organic Dynamics Program supports the continuing work of Professor William C. Agosta at Rockefeller University. Molecules that contain a light absorbing group, and in addition, a carbon-carbon double and triplet bond will be irradiated. The intermediates in these reactions will be investigated by observing the final products of the reactions. These intermediates will be generated by other methods to provide more insight into the electronic state and nature of the intermediates. The role of energetics of excited states and structure of certain nitrogen containing molecules in the intramolecular transfer of a hydrogen will be studied as well.
