Mechanisms of ground and excited state organic reactions

Organic chemistry is the study of the properties and reactions of carbon containing compounds. When reactions of these compounds occur, bonds between atoms are made and broken as the reactant is converted to the product. The term "mechanism" is used to describe the details of these bond changes: which bond is made or broken first and are there reactive, non-isolable intermediates on the pathway. The experimental evidence for reaction mechanisms and the logical methods by which these mechanisms are formulated from experimental data is the subject of my research. The understanding of reaction mechanisms is fundamental research and leads to the prediction and development of new reactions. The organic reactions we study are of two different types; ground state and excited state. In a ground state reaction the only source of energy provided to break chemical bonds is heat. In some cases, even the heat available at room temperature is enough to make the reactions proceed rapidly; in other cases, the temperature must be raised by external heating. In excited state reactions, the extra energy available to the reactant is provided by light (photons) in the visible or ultraviolet range. Since the energy provided by a photon is sufficient to break chemical bonds, excited states are normally millions of times more reactive than ground states and moreover, often react by completely different pathways to give different products. The study of organic photochemical reactions is much less advanced than the study of ground state reactions. Consequently, reliable predictions about the structure and yield of the products to be obtained from a new reactant are still not possible. Our overall goal is to improve the fundamental understanding of both ground and excited state reactivity.