A thorough investigation of the geometric parameters which govern the interaction of one part of a molecule with another part of the same molecule will be conducted. The interactions to be investigated will include processes which result in energy transfer and/or chemical reaction. The base absorbing chromophore to be investigated will be an aromatic ketone. By careful choice of geometry in the aromatic ketone, it will be possible to define for the first time the restrictions imposed by atomic and electronic orientation on chemical processes of excited aryl ketones. The projects to be investigated will include: (1) measurement of the kinetics of processes involving triplet cycloaddition, hydrogen abstraction and intramolecular triplet energy transfer; (2) observation of biradical partitioning; and (3) determination of the spin multiplicity of benzene-halogen cleavage reactions. Classical photochemical and photophysical methods will be utilized throughout the project to provide a thorough examination of the mechanisms involved. %%% This grant from the Organic Dynamics Program supports the continuing work of Professor Peter J. Wagner at Michigan State University. The investigation will be aimed at probing the means by which energy is transferred from one part of a molecule to another. This work is particularly important since the process of how two parts of the same molecule interact is at the heart of many chemical processes which occur in both natural and synthetic molecules. The work to be conducted will provide the chemist, as well as other scientists, with a basic understanding of how chemical processes occur upon absorption of a photon of light. From this project will emerge a fundamental understanding of the constraints placed upon light induced processes by geometrical configurations of the groups comprising photoreactive molecules.
