jp037795r_si_001.pdf (759.32 kB)
Theoretical Prediction of Benzyne-Like Species in Pyrene Diradicals
journal contribution
posted on 2004-06-10, 00:00 authored by I. García-Cruz, J. M. Martínez-Magadán, J. M. Bofill, F. IllasThe different products that can be obtained from pyrene dehydrogenation have been studied by means of
hybrid density functional theory. Most of the didehydrogenated species exhibit a diradical character. This is
supported by the closeness between the geometry and energy of singlet and triplet states and the open-shell
nature of the singlet state. However, three didehydrogenated species have been found to exhibit a closed-shell singlet electronic ground state. The analysis of the electronic structure, the formation energy of these
didehydrogenated species, and their geometrical structure reveals that these three didehydrogenated species
are better described as benzyne-like moieties; two of them are of o- and one of m-benzyne character. The two
o-benzyne species have lower energies than the m-benzyne and are favored upon diradical formation. This
interpretation is fully supported by the analysis of multiconfigurational wave functions and the order of stabilities
confirmed by second-order multireference perturbation theory calculations. A possible implication of the
reactivity of these benzyne-like species in asphaltene formation is discussed.