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: 2023-02-18

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: http://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