Photocatalytic function of the B12 complex with the cyclometalated iridium(iii ) complex as a photosensitizer under visible light irradiation
| Autor: | Gyurim Park, Youngmin You, Hisashi Shimakoshi, Sinheui Kim, Hui Tian, Yoshio Hisaeda |
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| Rok vydání: | 2018 |
| Předmět: |
Reaction mechanism
Quenching (fluorescence) 010405 organic chemistry chemistry.chemical_element 010402 general chemistry Photochemistry 01 natural sciences 0104 chemical sciences Catalysis Inorganic Chemistry chemistry.chemical_compound Electron transfer chemistry Photocatalysis Phenyl group Photosensitizer Iridium |
| Zdroj: | Dalton Transactions. 47:675-683 |
| ISSN: | 1477-9234 1477-9226 |
| Popis: | A visible light induced three-component catalytic system with the cobalamin derivative (B12) as a catalyst, the cyclometalated iridium(iii) complex (Irdfppy, Irppy, Irpbt and [Ir{dF(CF3)ppy}2(dtbpy)]PF6) as a photosensitizer and triethanolamine as an electron source under N2 was developed. This catalytic system showed a much higher catalytic efficiency than the previous catalytic system using [Ru(ii)(bpy)3]Cl2 as the photosensitizer for the dechlorination reaction of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT). Noteworthy is the fact that the remarkable high turnover number (over ten thousand) based on B12, which ranks at the top among the reported studies, was obtained when Irdfppy was used as a photosensitizer. This photocatalytic system was also successfully applied to the B12 enzyme-mimic reaction, i.e., the 1,2-migration of the phenyl group of 2-bromomethyl-2-phenylmalonate. The plausible reaction mechanism was proposed, which involved two quenching pathways, an oxidative quenching pathway and a reductive quenching pathway, to be responsible for the initial electron transfer of the excited-state photosensitizers during the DDT dechlorination reaction. Transient photoluminescence experiments revealed that the oxidative quenching of the photosensitizer dominated over the reductive quenching pathway. |
| Databáze: | OpenAIRE |
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