Sunlight-Driven Dehydrogenative Oxidation Photocatalysis by a Mononuclear Complex Acting as both Chromophore and Catalyst
| Autor: | Weizhong Chen, Francisca R. Rocha, Reginaldo C. Rocha, Brian L. Scott |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
photochemistry proton-coupled electron transfer photooxidation chemistry.chemical_element solar catalysis General Chemistry Chromophore Electron acceptor Photochemistry Redox Catalysis Ruthenium Benzaldehyde chemistry.chemical_compound chemistry Benzyl alcohol Proton-coupled electron transfer ruthenium |
| Zdroj: | Journal of the Brazilian Chemical Society v.31 n.11 2020 Journal of the Brazilian Chemical Society Sociedade Brasileira de Química (SBQ) instacron:SBQ Journal of the Brazilian Chemical Society, Volume: 31, Issue: 11, Pages: 2421-2429, Published: 30 OCT 2020 |
| Popis: | Under simulated solar irradiation in the visible spectral region, the catalytically active RuIV-oxo species [Ru(O)(bpy)(tppz)]2+ (tppz = tetrapyridylpyrazine, a strongly π-accepting tridentate N, N, N-ligand) is produced directly from a single metal-to-ligand charge-transfer (MLCT) photoexcitation of the resting RuII-aquo complex [Ru(H2O)(bpy)(tppz)]2+ in aqueous media containing an electron acceptor. This photoinduced path to 2-electron/2-proton activation of a mononuclear catalyst (i.e., without a paired chromophoric unit) is enabled by the thermodynamic instability of the intermediate RuIII-hydroxo species [Ru(OH)(bpy)(tppz)]2+, which promptly disproportionates into the RuIV-oxo and RuII-aquo states as electrochemically observed by cyclic and pulse voltammetries in a wide range of pH. The proton-coupled multielectron photocatalytic capability of the complex in neutral aqueous solutions, at room conditions, was demonstrated through the dehydrogenative oxidation of benzyl alcohol into benzaldehyde with a product selectivity of about 100%. The performance of this mononuclear complex acting as chromophore/catalyst is comparable to that of the previously reported dinuclear complex [(tpy)Ru(tppz)Ru(HxO)(bpy)]4+. In addition to the characterization of redox and spectroscopic properties for the [Ru(L)(bpy)(tppz)]n+ derivatives with L = Cl- or HxO, structural analysis of the precursor chloro complex [RuCl(bpy)(tppz)](PF6) was also performed by single-crystal X-ray diffraction in this work. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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