View : 466 Download: 0
Photocatalytic hydrogen evolution using a Ru(ii)-bound heteroaromatic ligand as a reactive site
- Title
- Photocatalytic hydrogen evolution using a Ru(ii)-bound heteroaromatic ligand as a reactive site
- Authors
- Sawaki T.; Ishizuka T.; Namura N.; Hong D.; Miyanishi M.; Shiota Y.; Kotani H.; Yoshizawa K.; Jung J.; Fukuzumi S.; Kojima T.
- Ewha Authors
- Shunichi Fukuzumi; 정지은
- SCOPUS Author ID
- Shunichi Fukuzumi; 정지은
- Issue Date
- 2020
- Journal Title
- Dalton Transactions
- ISSN
- 1477-9226
- Citation
- Dalton Transactions vol. 49, no. 47, pp. 17230 - 17242
- Publisher
- Royal Society of Chemistry
- Indexed
- SCIE; SCOPUS
- Document Type
- Article
- Abstract
- A RuII complex, [RuII(tpphz)(bpy)2]2+ (1) (tpphz = tetrapyridophenazine, bpy = 2,2′-bipyridine), whose tpphz ligand has a pyrazine moiety, is converted efficiently to [RuII(tpphz-HH)(bpy)2]2+ (2) having a dihydropyrazine moiety upon photoirradiation of a water-methanol mixed solvent solution of 1 in the presence of an electron donor. In this reaction, the triplet metal-to-ligand charge-transfer excited state (3MLCT∗) of 1 is firstly formed upon photoirradiation and the 3MLCT∗ state is reductively quenched with an electron donor to afford [RuII(tpphz-)(bpy)2]+, which is converted to 2 without the observation of detectable reduced intermediates by nano-second laser flash photolysis. The inverse kinetic isotope effect (KIE) was observed to be 0.63 in the N-H bond formation of 2 at the dihydropyrazine moiety. White-light (380-670 nm) irradiation of a solution of 1 in a protic solvent, in the presence of an electron donor under an inert atmosphere, led to photocatalytic H2 evolution and the hydrogenation of organic substrates. In the reactions, complex 2 is required to be excited to form its 3MLCT∗ state to react with a proton and aldehydes. In photocatalytic H2 evolution, the H-H bond formation between photoexcited 2 and a proton is involved in the rate-determining step with normal KIE being 5.2 on H2 evolving rates. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations on the reaction mechanism of H2 evolution from the ground and photo-excited states of 2 were performed to have a better understanding of the photocatalytic processes. © 2020 The Royal Society of Chemistry.
- DOI
- 10.1039/d0dt03546g
- Appears in Collections:
- 자연과학대학 > 화학·나노과학전공 > Journal papers
- Files in This Item:
There are no files associated with this item.
- Export
- RIS (EndNote)
- XLS (Excel)
- XML