Theoretical studies of the photochemical dynamics of acetylacetone: isomerzation, dissociation, and dehydration reactions.

Abstract

The potential energy surfaces of the C-O cleavage, rotational isomerization, keto-enolic tautomerization, and dehydration reactions of acetylacetone in the lowest triplet and ground states have been determined using the complete active space self-consistent field and density functional theory methods. The main photochemical mechanism obtained indicates that the acetylacetone molecule in the S(2)((1)pipi*) state can relax to the T(1)((3)pipi*) state via the S(2)-S(1) vibronic interaction and an S(1)/T(1)/T(2) intersection. The C-O fission pathway is the predominant dissociation process in the T(1)((3)pipi) state. Rotational isomerization reactions proceed difficultly in the ground state but very easily in the T(1)((3)pipi*) state. Keto-enolic tautomerization takes place with little probability for acetylacetone in the gas phase.

• Authors: Xue-Bo Chen, Wei-Hai Fang, David Lee Phillips
• Journal: The journal of physical chemistry. A (J Phys Chem A) Vol. 110 Issue 13 Pg. 4434-41 (Apr 06 2006) ISSN: 1089-5639 [Print] United States
• PMID: 16571047 (Publication Type: Journal Article)