The T(1) (3)(pi-pi*)/S(0) intersections and triplet lifetimes of cyclic alpha,beta-enones

E García-Expósito; M J Bearpark; R M Ortuño; V Branchadell; M A Robb; S Wilsey

doi:10.1021/jo015865p

The T(1) (3)(pi-pi*)/S(0) intersections and triplet lifetimes of cyclic alpha,beta-enones

J Org Chem. 2001 Dec 28;66(26):8811-4. doi: 10.1021/jo015865p.

Authors

E García-Expósito¹, M J Bearpark, R M Ortuño, V Branchadell, M A Robb, S Wilsey

Affiliation

¹ Department of Chemistry, King's College London, Strand, London WC2R 2LS, U.K.

PMID: 11749611
DOI: 10.1021/jo015865p

Abstract

The ground and triplet excited states of cycloheptenone, cyclohexenone, and cyclopentenone have been studied using CASSCF calculations. For these three molecules, the difference in energy (DeltaE) between the twisted T(1) (3)(pi-pi*) minimum and T(1) (3)(pi-pi*)/S(0) intersection increases as the flexibility of the ring decreases. A strong positive correlation between DeltaE and the natural logarithm of the experimentally determined triplet lifetimes (ln tau) is found, suggesting that DeltaE predominantly determines the relative radiationless decay rates of T(1).