Quantum Chemical Study of the Photocoloration Reaction in the Napthoxazine Series

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 110; no. 14; pp. 4759 - 4771
• Main Authors: Maurel, F, Aubard, J, Millie, P, Dognon, J. P, Rajzmann, M, Guglielmetti, R, Samat, A
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 13.04.2006
• Subjects: Chemical Sciences; or physical chemistry; Theoretical and
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp054976f

Ab initio and semiempirical quantum mechanical calculations were performed to study the electronic spectra of spiroxazine photochromic compounds as well as the corresponding photoisomers. Ground-state geometries were optimized based on density functional theory (DFT). Excitation energies of the different forms were calculated using the time-dependent density functional theory (TD-DFT) method. Semiempirical calculations including configuration interactions were performed to detail the mechanism of ring opening in excited states. On the basis of the obtained potential energy profile, a complete mechanism of photocoloration able to clarify some experimental findings is provided. A correlation of the experimental quantum yield of photocoloration with the calculated properties as a function of substituent effects is proposed.