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Gas phase unimolecular 1,1‐hydrogen elimination: Reaction mechanism and isotope effect
Author(s) -
Barone Vincenzo,
Bianchi Nadia,
Lelj Francesco,
Russo Nino
Publication year - 1984
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560260506
Subject(s) - mndo , chemistry , kinetic isotope effect , carbocation , reaction mechanism , computational chemistry , reaction rate constant , gas phase , mechanism (biology) , elimination reaction , deuterium , molecule , photochemistry , kinetics , atomic physics , organic chemistry , catalysis , physics , quantum mechanics
The mechanism of unimolecular 1,1‐elimination of H 2 from carbocations has been investigated by the semiempirical MNDO method in view of its very good performances in the analogous elimination from H 2 CO. Contrary to previous suggestions, the critical configuration obtained at the MNDO level is characterized by a reduced symmetry with respect to the reacting molecule and by a very short HH distance. RRKM computations of the rate constants and isotope effect employing MNDO results for the activation energies and vibrational frequencies indicate also that the present, nonsynchronous mechanism is compatible with all the available experimental data.