Absolute Kinetic Studies of Carbene Reactions

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A study of carbenes and related reactive intermediates by laser flash photolysis will be conducted. Spectroscopic and kinetic measurements of these highly reactive intermediates in solution will be made. The research projects will include investigation of: (1) the properties of nucleophilic carbenes; (2) the kinetics of carbene/metal salt reactions (carbenoid formation); (3) the properties of "push pull" carbenes as well as pyridyl and pyridinium carbenes; (4) the effects of fluoro and methoxy substituents in modulating intramolecular carbene rearrangements; and (5) the fragmentation of oxycarbenes to carbocations. These studies will be of particular importance in providing insight and understanding for reactions that are characterized by low activation energy barriers. %%% This grant from the Organic Dynamics Program supports the continuing work of Professor Robert A. Moss at Rutgers University. These studies will be centered around the production and reactions of carbenes, which are species that contain a carbon atom with two formal bonds rather than four bonds as found in stable carbon compounds. Carbenes are reactive intermediates that are very short-lived. Special flash laser techniques will be employed to observe these reactive intermediates and to study the rate at which they react. Carbenes can undergo reaction to give other reactive intermediates. For example, carbenes can react with lithium chloride to generate an adduct called a carbenoid with the normal complement of four bonds. With appropriate substitution, carbenes can give another reactive intermediate, a carbocation, which contains a carbon with three bonds and a net one unit of positive charge. These reactions will provide a means to study some of the important reactive intermediates in organic chemistry.