Singlet−Triplet Gap in α-n-Dehydrotoluene and Related Biradicals: An ab Initio Configuration Interaction Study

Autor:	N. Ben-Amor, R. Caballol, J. Cabrero
Rok vydání:	1999
Předmět:	Character (mathematics) Chemistry Ab initio Electron Singlet state Physical and Theoretical Chemistry Atomic physics Configuration interaction Ground state Basis set
Zdroj:	The Journal of Physical Chemistry A. 103:6220-6224
ISSN:	1520-5215 1089-5639
DOI:	10.1021/jp990123+
Popis:	By means of ab initio difference-dedicated configuration interaction (DDCI2) calculations, singlet−triplet gaps of α-n-dehydrotoluene (n = 2, 3, or 4), 2-o, 2-m, 2-p, and α-3-didehydro-5-methyl-6-hydroxybenzene, 4, biradicals have been determined. Calculations have been performed with a 6-31G** basis set. A triplet ground state has been found for both the ortho and para isomers of 2, with quite similar gaps: 6.5 and 6.8 kcal mol-1, respectively. For the meta-substituted compounds, 2-m and 4, the ground state is found to be a singlet with a gap of −2.1 kcal mol-1 for both compounds. The intermediate in the synthesis of 4 and 2,6-dimethylcyclohexa-2,5-dien-1-on-4-ylidene, 3, has also been considered. Its triplet ground state does not present a pure carbenic character, but the single electrons are strongly localized in different centers.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::64cb1adf208cc5e3433d41e29c251446 https://doi.org/10.1021/jp990123+ Zobrazit plný text záznamu