Photo-CIDNP Reveals Different Protonation Sites Depending on the Primary Step of the Photoinduced Electron-/Proton-Transfer Process with Ru(II) Polyazaaromatic Complexes
| Autor: | Epiphanie Mugeniwabagara, Michel Luhmer, Ludovic Troian-Gautier, Andrée Kirsch-De Mesmaeker, Luca Fusaro, Emilie Cauet |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Hydroquinone
010405 organic chemistry CIDNP Chemistry Protonation General Chemistry Electron 010402 general chemistry Photochemistry 01 natural sciences Biochemistry Catalysis 0104 chemical sciences Electron transfer chemistry.chemical_compound Colloid and Surface Chemistry Ultrafast laser spectroscopy Density functional theory Spectroscopy |
| Zdroj: | Journal of the American Chemical Society. 139(42):14909-14912 |
| ISSN: | 1520-5126 0002-7863 |
| Popis: | The excited-state quenching of [Ru(TAP)2(HAT)]2+ (TAP = 1,4,5,8-tetraazaphenanthrene, HAT= 1,4,5,8,9,12-hexaazatriphenylene) by hydroquinone (H2Q), N-acetyl-tyrosine (N-Ac-Tyr) or guanosine-5′-monophosphate (GMP) was investigated at various pH values. The quenching occurs via electron/proton transfer, as evidenced by transient absorption spectroscopy and confirmed by 1H photochemically induced dynamic nuclear polarization (photo-CIDNP). Reductive quenching also occurs in strongly acidic solution despite a much shorter lifetime of the protonated excited-state complex. Photo-CIDNP revealed a different mechanism at low pH, involving protonation before electron transfer and yielding a distinct protonated monoreduced complex. The experimental photo-CIDNP patterns are consistent with density functional theory calculations. This work highlights the power of 1H photo-CIDNP for characterizing, at the atomic level, transient species involved in electron-transfer processes. |
| Databáze: | OpenAIRE |
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