Singlet benzyne thermochemistry: A CASPT2 study of the enthalpies of formation
1996 (English)In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 258, no 3-4, 409-415 p.Article in journal (Refereed) Published
The enthalpies of formation for singlet benzynes were examined at the CASPT2 (second order perturbation theory, based on a complete active space SCF reference function) level of theory, The study employed isodesmic reactions in order to minimize the influence of systematic errors of the method. The results obtained for m- and p-benzyne were found to dispute earlier experimentally deduced values; a discrepancy of about 5 kcal/mol was observed. As a consequence, the enthalpy of reaction of the so called Bergman reaction, deduced previously from the experimental enthalpy of formation of p-benzyne, seems to be overestimated by about 5 kcal/mol. Furthermore, it was observed that the CCSD(T) method (coupled cluster singles and doubles with a perturbatative estimate of the triples contribution) is inappropriate for a balanced treatment of the Bergman reaction, due to the extensive differences in the electronic structures of the two reactants.
Place, publisher, year, edition, pages
1996. Vol. 258, no 3-4, 409-415 p.
IdentifiersURN: urn:nbn:se:uu:diva-143933DOI: 10.1016/0009-2614(96)00653-7ISI: A1996VC07100015OAI: oai:DiVA.org:uu-143933DiVA: diva2:394345