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A bioinspired cobalt catalyst based on a tripodal imidazole/pyridine platform capable of water reduction and oxidation

2023; Elsevier BV; Volume: 242; Linguagem: Inglês

10.1016/j.jinorgbio.2023.112162

1873-3344

Krista M. Kulesa, Diego S. Padilha, Bishnu Thapa, Shivnath Mazumder, Yaroslav Losovyj, H. Bernhard Schlegel, Marciela Scarpellini, Cláudio N. Verani,

Advanced battery technologies research

The prototypical drug carrier [CoII(L1)Cl]PF6 (1), where L1 is a tripodal amine bound to pyridine and methyl-imidazoles, had its electrocatalytic water splitting activity studied under different pH conditions. This species contains a high-spin 3d7 CoII metal center, and is capable of generating both H2 from water reduction and O2 from water oxidation. Turnover numbers reach 390 after 3 h for water reduction. Initial water oxidation activity is molecular, with TONs of 71 at pH 7 and 103 at pH 11.5. The results reveal that species 1 can undergo several redox transformations, including reduction to the 3d8 CoI species that precedes a LS3d6 hydride for water reduction, as well as nominal CoIVO and CoIII-OOH species required for water oxidation. Post-catalytic analyses confirm the molecular nature of reduction and support initial molecular activity for oxidation.