Gas-phase kinetics and activation parameters for thermal [1,5] hydrogen shifts interconverting monodeuterium- labeled 1,3-cycloheptadienes.
The kinetics of thermal equilibrations among monodeuterium-labeled 1,3-cycloheptadienes in the gas phase followed from 154 to 190 degrees C provide activation parameters for the [1,5] shift of a single hydrogen: E(a) = (27.5 +/- 0.9) kcal/mol and log A = 9.7 [corrected] +/- 0.4. These activation parameters imply a comparatively low E(a) barrier balanced by demandingly specific geometric constraints, for DeltaS (170 degrees C) = -17 [corrected] e.u.
Baldwin
John E
JE
Department of Chemistry, Syracuse University, Syracuse, New York 13244, USA. jbaldwin@syr.edu
Raghavan
Anuradha S
AS