Green Chemistry
Paper
process involves the formation of a C–C bond between the
phenyl group and the non-substituted carbon atom of the EA
ligand. Previous studies show that the formation of the bond
involving the substituted carbon atom of the alkene involves a
very large energy barrier.47 In this step there is no notable
difference between the neutral and cationic pathways. The
calculated Gibbs reaction energy of the neutral path is
−14.93 kcal mol−1 which is comparable with −14.83 kcal
mol−1 for the cationic path. The next step is β-hydride elimin-
ation to give a new CvC bond in complexes 8 and 13 and to
finally form carbonyl product along with the formation of 9
and 12. The Gibbs reaction energies for the dissociation of 7
to the complex 8 are significantly lower than the dissociation
of 12 to complex 13. The calculated ΔGs are 10.65 and
33.40 kcal mol−1, respectively, for the former and latter reac-
tions. In fact, this step differentiates the neutral versus cationic
pathways. The final step involves −10.67 and 7.92 kcal mol−1
energy to give complexes 9 and 14. However, despite these
differences, the Gibbs free energy profiles for the two neutral
and cationic mechanisms do not change sufficiently to suggest
Notes and references
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Acknowledgements
Authors gratefully acknowledge financial support for this work
from the Research Council of University of Shiraz and the 26 A. Kamal, V. Srinivasulu, B. N. Seshadri, N. Markandeya,
Council of Iran National Science Foundation.
A. Alarifib and N. Shankaraiah, Green Chem., 2012, 14, 2513.
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