Variational transition state theory as a tool to determine kinetic selectivity in reactions involving a valley-ridge inflection point.
Variational transition state theory has been used to calculate the kinetic isotope effects affecting product ratios in the reaction between (1)O(2) and d(6)-tetramethylethylene. The minimum energy path on the potential energy surface for this process reaches a valley-ridge inflection point and then bifurcates leading to the two final products. Using canonical variational transition state theory, two distinct dynamical bottlenecks were located corresponding to the H- and the D-abstraction, respectively. The calculated KIE at 263 K turns out to be 1.126. Analogously, a H/T KIE of 1.17 at the same temperature has been found for the reaction of (1)O(2) with the tritiated derivative of tetramethylethylene.
Contribution from the Departament de Química, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona), Spain.
Angels
A
Ganzález-Lafont
Miquel
M
Moreno
José M
JM
Lluch