This grant in Organic and Macromolecular Chemistry provides support for the research of Dr. Robert Moss, Rutgers University. The work is focused on the direct observational studies of carbenes, which are a class of important reaction intermediates in organic chemistry. They are important because of their unusual reactivity which arises because carbenes are electron deficient and can exist in more than one accessible electronic state. Fundamental studies of carbenes and other highly reactive intermediates will be carried out by direct spectroscopic observation and absolute kinetic methods. The diazirine halide exchange reaction will be used to prepare novel diazirine precursors for dimethoxycarbene and fluoromethoxycarbene. For dimethoxycarbene, spectroscopic, absolute kinetic, activation parameter, and reactivity studies will define the behavior of this representative nucleophilic carbene. Parallel studies will be made with fluoromethoxycarbene. The free energies of activation of the carbene/alkene addition reactions will be determined and analyzed for enthalpy/entropy partition. Other carbenes to studied include methoxymethylcarbene, fluoromethylcarbene, and dimethylaminomethoxycarbene. Activation parameters will also be measured for additions of phenylhalocarbenes to hindered alkenes, where unusual behavior has already been observed. Finally, several methods of generating carbonium ion from diazirines and carbenes will be studied.
