This award is made in the Organic Dynamics Program in the support of the research of Prof. Daniel Falvey at the University of Maryland. The research deals with chemical and spectroscopic studies of nitrenium ions, photochemically generated from N-aminopyridinium salts. Two specific areas will be addressed: (1) the solution reactivity of nitrenium ions, particularly with nucleophiles, and (2) defining the structural features of nitrenium ions which control their singlet-triplet energy gaps. The former will be probed by laser flash photolysis and photothermal beam deflection calorimetry and the latter by low temperature electron paramagnetic resonance spectroscopy. Experimental studies will be complemented by semi-empirical and ab initio calculations. Nitrenium ions, as reactive intermediates in organic reactions, have not been well explored. This study of the structural features which control their singlet-triplet energy gaps, will provide fundamental information which will aid in the design of new magnetic materials. Additionally, the study of the reactivity of nitrenium ions towards nucleophiles will shed light on their role in DNA damage and carcinogenesis.
