An investigation of electron spin resonance couplings of biradical species in a variety of different environments will be conducted. Time-resolved electron paramagnetic resonance will be used to study the effects of substituents, geometrical constraints, distance, solvent, and temperature between the flexible organic biradicals. Media to be included in the investigation include organic solvents, super critical fluids, vesicles, micelles, liquid crystals, polymers, and zeolites. The magnitude of the size of the coupling constants will provide critical information with respect to through solvent versus through bond interactions in weakly coupled systems. In the case of the polymer systems, strategic placement of the biradical sites in the polymer chain will allow rotational barriers to be probed both at the end and at the center of the polymer. In addition, polymers containing critical concentrations of ketones will be synthesized and investigated to define the parameters important in development of the next generation of photodegradable macromolecular materials. %%% This grant from the Organic Dynamics Program supports the investigation of biradical interactions in chemical systems by Professor Malcolm Forbes at the University of North Carolina at Chapel Hill. It is critical to understand the method by which different parts of molecular systems communicate with each other electronically in order to be in a position to design molecules that are capable of performing specific functions in the context of a molecular device. In addition, the synthesis of new materials with potential use as photodegradable plastics will be guided by the results of the biradical studies. Also photochemically reactive polymers will be designed to increase the adhesion between traditionally non-interactive polymeric materials.
