The rates and mechanisms of prototype isomerization and fragmentation reactions of small hydrocarbons will be examined. The molecules selected for study are sufficiently small to allow high-level molecular orbital calculation for comparison to experiment. The studies will include: (1) the rate of cis, trans ethylene-1,2-d2 isomerization, (2) the relative energy barriers for structural vs geometric isomerizations of cyclopropane-1, 2-d2 and cyclopropane-1,2,3-d3, (3) energy barriers for fragmentation of cyclobutane-1,3-d2, (4) the stereochemistry of conversion of bicyclo 1.1.0 butane-2,2-d2 to butadiene, (5) rate and mechanism of the 3,4-elimination of molecular hydrogen from cyclopentene, and (6) the stereochemistry of reactions of vinylcyclobutane-2,3-d2 to cyclohexene and to ethylene plus butadiene. This grant from the Organic Dynamics Program supports the continuing work of Professor David K. Lewis at Colgate University. These results of this research will provide fundamental information about processes where carbon-carbon and carbon-hydrogen bonds are broken and formed. A long-standing question about these processes is whether the bonds are broken in a stepwise manner or in one step. These mechanistic aspects will be probed by the thermal decomposition of deuterium labeled compounds and compounds with unique three-dimensional structure. Theoretical predictions, based on sophisticated calculations, will be compared to experimental results which will be a test of the theory.
