Dr. Neuman received his B.S. in 1959 from University of California, Los Angeles. Dr. Neuman then went on to obtain his Ph.D., in 1963, from the California Institute of Technology. Later, Dr. Neuman became a NSF Postdoctoral Fellow from 1962 to 1963 at Columbia University and a NIH Special Research Fellow from 1971 to 1972.
My research in physical organic chemistry has been directed towards understanding dynamics of organic reactions. Areas of interest have included effects of pressure on organic reactions, NMR studies of hindered rotation about C-N partial double bonds in amides and homologous systems, studies of solvent effects on thermal and photochemical decompositions of radical initiators, and the use of computational chemistry methods to examine changes in molecular structure which occur during rotation about partial double bonds.
At the present time the focus of my academic activities is on undergraduate education in general chemistry and organic chemistry. I am currently writing a textbook for the sophomore chemistry course in organic chemistry.
Previously, my research group utilized effects of high pressure on rates and products of radical initiator decomposition reactions as mechanistic probes. (See R.C. Neuman, Accts. Chem. Research, 5, 381 ). When chemical reactions take place, bonds are made or broken, conformations of molecules change, and the solvation of reactants often differs from that of the transition state and products. These changes usually mean that volumes of transition states are different from those of the reactants. When this is the case, pressure applied to the reacting system alters the reaction rate. When rates increase with pressure, the apparent volume of the transition state is smaller than that of the reactants, and when rates decrease the volume is larger. Knowing which is the case can be very helpful in understanding the mechanistic details of a chemical reaction.
Our early kinetic studies of the barriers to rotation about the C-N bond in compounds of the general structure R-C(=X)-NMe2 using NMR total lineshape methods, provided the first collection of good rate data permitting a comparison of the effects of variation of X and the solvent. References to all of these studies are summarized in Neuman, R.C., Jr.; Jonas, V., J. Org. Chem. 1974, 39, 929.
We have also studied effects of solvent and reactant structure at atmospheric pressure on rates of organic reactions. Some of the effects of pressure on chemical reactions may be due to increases in solvent viscosity with increasing pressure. Viscosity variation studies at atmospheric pressure utilizing solvent variation can provide information about this as well as information about potential differences between miscroscopic and macroscopic viscosity. These types of studies have been utilized to probe the mechanisms of thermal decomposition of cis-diazenes.
Selected Research Publications
Neuman, Jr., R.C., Gunderson, H.J., "On the Solvent Dependence of Cis-Diazene Inversion", J. Org. Chem., 57, 1641-1643 (1992).
Neuman, Jr., R.C., Berge, C.T., Binegar, G.A., Adam, W., Nishizawa, Y., "Cis-Diazenes. Pressure Effects on Their Thermal Deazatization and Isomerization Reactions," J. Org. Chem., 55, 4564-4568 (1990).
Neuman, Jr., R.C., Grow, R.H., Binegar, G.A., Gunderson, H.J., "Cis-Diazenes. Viscosity Effects, One-Bond Scission, and Cis-trans Isomerization," J. Org. Chem., 55, 2682-2688 (1990).
Neuman, Jr., R.C., Frink, M.E., "Evidence for Viscosity Effects on Disproportionation-Combination Ratios of tert-Butyl Radicals in Solution," J. Org. Chem., 48, 2430-2432 (1983).
Neuman, Jr., R.C., and Sylwester, A.P., "Evidence for a Radical Decomposition Mechanism for Disphenyl-N-benzylketene Imine," J. Org. Chem., 48, 2285-2287 (1983).