Author, as appears in the article.: Josep Casellas; Mar Reguero
Department: Química Física i Inorgànica
URV's Author/s: Reguero de la Poza, Maria del Mar
Keywords: Mecanismes de reacció Fotoquímica
Abstract: Phenalenone derivatives are involved in plant defense strategies, producing molecular singlet oxygen in a photosensitization process. Many experimental and theoretical studies determined that phenalenone (PN) can carry out this process with a quantum yield close to one. However, it has been observed that the efficiency of some of its derivatives is much lower. This is the case of 9-phenylphenalenone (9-PhPN). To elucidate the factors that determine the different photochemistry of PN and its derivate 9-PhPN, we have developed a CASSCF/CASPT2 study where several deactivation paths through the lowest excited states have been explored. We have found that the characteristics of the low-lying excited states are similar for both PN and 9-PhPN in the areas near the geometry of excitation. Consequently, the first processes that take place immediately after absorption are possible in both systems, including the population of the triplet state responsible for oxygen sensitization. However, 9-PhPN can also undergo cyclisation by a bond formation between the carbonyl oxygen and a carbon atom of the phenyl substituent. This process competes favourably with population of triplet states and is responsible for the decrease of the quantum yield of oxygen sensitization in 9-PhPN relative to PN.
Thematic Areas: Química Physics, atomic, molecular & chemical Physical and theoretical chemistry Odontología Medicine (miscellaneous) Medicina ii Medicina i Materiais Interdisciplinar Geociências General medicine Farmacia Ensino Engenharias iv Engenharias iii Engenharias ii Ciências biológicas ii Ciências biológicas i Ciências ambientais Ciências agrárias i Chemistry, physical Biotecnología Biodiversidade Astronomia / física
licence for use: https://creativecommons.org/licenses/by/3.0/es/
ISSN: 15205215
Author's mail: mar.reguero@urv.cat
Author identifier: 0000-0001-9668-8265
Last page: 821
Record's date: 2024-09-07
Journal volume: 122
Papper version: info:eu-repo/semantics/submittedVersion
Link to the original source: https://pubs.acs.org/doi/10.1021/acs.jpca.7b11569
Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
Papper original source: Journal Of Physical Chemistry a. 122 (3): 811-821
APA: Josep Casellas; Mar Reguero (2018). Photosensitization versus Photocyclization: competitive reactions of phenylphenalenone in its role as phytoanticipins in plant defense strategies. Journal Of Physical Chemistry a, 122(3), 811-821. DOI: 10.1021/acs.jpca.7b11569
Article's DOI: 10.1021/acs.jpca.7b11569
Entity: Universitat Rovira i Virgili
Journal publication year: 2018
First page: 811
Publication Type: Journal Publications