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Time-Resolved Insight into the Photosensitized Generation of Singlet Oxygen in Endoperoxides.

Martínez-Fernández L, González-Vázquez J, González L, Corral I - J Chem Theory Comput (2014)

Bottom Line: Electronic excitation of endoperoxides triggers two competing pathways, cycloreversion and O-O homolysis, that result in the generation of singlet oxygen and oxygen diradical rearrangement products.The triplet states do not intervene in this mechanism, as opposed to the O-O homolysis where the exchange of population between the singlet and triplet manifolds is remarkable.In line with recent experiments performed on the larger anthracene-9,10-endoperoxide, upon excitation to the spectroscopic ππ* electronic states, the primary photoreactive pathway that governs deactivation of endoperoxides is O-O homolysis with a quantum yield of 65%.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Química, Universidad Autónoma de Madrid , 28049 Cantoblanco, Madrid, Spain.

ABSTRACT

A synergistic approach combining high-level multiconfigurational static calculations and full-dimensional ab initio surface hopping dynamics has been employed to gain insight into the photochemistry of endoperoxides. Electronic excitation of endoperoxides triggers two competing pathways, cycloreversion and O-O homolysis, that result in the generation of singlet oxygen and oxygen diradical rearrangement products. Our results reveal that cycloreversion or the rupture of the two C-O bonds occurs via an asynchronous mechanism that can lead to the population of a ground-state intermediate showing a single C-O bond. Furthermore, singlet oxygen is directly generated in its most stable excited electronic state (1)Δg. The triplet states do not intervene in this mechanism, as opposed to the O-O homolysis where the exchange of population between the singlet and triplet manifolds is remarkable. In line with recent experiments performed on the larger anthracene-9,10-endoperoxide, upon excitation to the spectroscopic ππ* electronic states, the primary photoreactive pathway that governs deactivation of endoperoxides is O-O homolysis with a quantum yield of 65%.

No MeSH data available.


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CHDEPO and Its Main Photoproducts: Benzoquinone (BQ) + H2 and Singlet Oxygen (1O2) + the Aromatic Hydrocarbon(B)
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sch1: CHDEPO and Its Main Photoproducts: Benzoquinone (BQ) + H2 and Singlet Oxygen (1O2) + the Aromatic Hydrocarbon(B)


Time-Resolved Insight into the Photosensitized Generation of Singlet Oxygen in Endoperoxides.

Martínez-Fernández L, González-Vázquez J, González L, Corral I - J Chem Theory Comput (2014)

CHDEPO and Its Main Photoproducts: Benzoquinone (BQ) + H2 and Singlet Oxygen (1O2) + the Aromatic Hydrocarbon(B)
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4325559&req=5

sch1: CHDEPO and Its Main Photoproducts: Benzoquinone (BQ) + H2 and Singlet Oxygen (1O2) + the Aromatic Hydrocarbon(B)
Bottom Line: Electronic excitation of endoperoxides triggers two competing pathways, cycloreversion and O-O homolysis, that result in the generation of singlet oxygen and oxygen diradical rearrangement products.The triplet states do not intervene in this mechanism, as opposed to the O-O homolysis where the exchange of population between the singlet and triplet manifolds is remarkable.In line with recent experiments performed on the larger anthracene-9,10-endoperoxide, upon excitation to the spectroscopic ππ* electronic states, the primary photoreactive pathway that governs deactivation of endoperoxides is O-O homolysis with a quantum yield of 65%.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Química, Universidad Autónoma de Madrid , 28049 Cantoblanco, Madrid, Spain.

ABSTRACT

A synergistic approach combining high-level multiconfigurational static calculations and full-dimensional ab initio surface hopping dynamics has been employed to gain insight into the photochemistry of endoperoxides. Electronic excitation of endoperoxides triggers two competing pathways, cycloreversion and O-O homolysis, that result in the generation of singlet oxygen and oxygen diradical rearrangement products. Our results reveal that cycloreversion or the rupture of the two C-O bonds occurs via an asynchronous mechanism that can lead to the population of a ground-state intermediate showing a single C-O bond. Furthermore, singlet oxygen is directly generated in its most stable excited electronic state (1)Δg. The triplet states do not intervene in this mechanism, as opposed to the O-O homolysis where the exchange of population between the singlet and triplet manifolds is remarkable. In line with recent experiments performed on the larger anthracene-9,10-endoperoxide, upon excitation to the spectroscopic ππ* electronic states, the primary photoreactive pathway that governs deactivation of endoperoxides is O-O homolysis with a quantum yield of 65%.

No MeSH data available.


Related in: MedlinePlus