| Title: | Unexpected promotional effects of alkyl-tailed ligands and anions on the electrochemical generation of ruthenium(IV)-oxo complexes | Authors: | Tsang, CS Lee, LYS Cheung, KC Chan, PH Wong, WL Wong, KY |
Issue Date: | 14-Jun-2021 | Source: | ChemElectroChem, 14 June 2021, v. 8, no. 12, p. 2221-2230 | Abstract: | Electro-generation of RuIV=O species from the RuII-aqua complex is a crucial step to excel the electrocatalytic water oxidation performance of ruthenium oxo complexes. We report herein the synthesis and X-ray crystal structural characterizations of new RuII-aqua complexes containing N-substituted 2,2′-dipyridylamine ligands (L) tagged with an alkyl chain of various lengths, [Ru(tpy)(L)(OH2)]2+. Cyclic voltammetric analyses show that the length of the alkyl chain exerts great influence on the electro-generation of RuIV=O species. The L with a longer alkyl chain in an acidic aqueous medium promotes the conversion of RuIII−OH to RuIV=O efficiently. Surprisingly, this conversion can be further enhanced by the presence of perchlorate anions. Chronocoulometric data reveal that the alkyl chain on L promotes the adsorption of the ruthenium complex on the electrode surface. Bulk electrolysis results indicate that the [Ru(tpy)(dppa)(OH2)]2+ (dppa=(2,2′-dipyridyl)-n-propylamine) gives the most active electrocatalytic water oxidation activity among the ruthenium-aqua complexes investigated in this study. | Keywords: | Coordination chemistry Electrocatalysis Pyridyl ligand Ruthenium(IV)-oxo complexes Water oxidation |
Publisher: | Wiley-VCH | Journal: | ChemElectroChem | ISSN: | 2196-0216 | DOI: | 10.1002/celc.202100364 |
| Appears in Collections: | Journal/Magazine Article |
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