Nickel is a Different Pickle: Trends in Water Oxidation Catalysis for Molecular Nickel Complexes
| Autor: | Hessels, Joeri, Masferrer-Rius, Eduard, Yu, Fengshou, Detz, Remko J., Klein Gebbink, Robertus J.M., Reek, Joost N.H., Sub Organic Chemistry and Catalysis, Organic Chemistry and Catalysis |
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| Přispěvatelé: | Sub Organic Chemistry and Catalysis, Organic Chemistry and Catalysis |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
inorganic chemicals
Tertiary amine General Chemical Engineering chemistry.chemical_element Homogeneous catalysis 02 engineering and technology 010402 general chemistry 01 natural sciences water splitting Catalysis chemistry.chemical_compound nickel Transition metal Cyclam Environmental Chemistry General Materials Science Full Paper Ligand structure-activity relationships Oxygen evolution Full Papers 021001 nanoscience & nanotechnology Combinatorial chemistry homogeneous catalysis 0104 chemical sciences Nickel General Energy chemistry water oxidation 0210 nano-technology |
| Zdroj: | ChemSusChem, 13(24), 6629. Wiley-VCH Verlag Chemsuschem |
| ISSN: | 1864-5631 |
| Popis: | The development of novel water oxidation catalysts is important in the context of renewable fuels production. Ligand design is one of the key tools to improve the activity and stability of molecular catalysts. The establishment of ligand design rules can facilitate the development of improved molecular catalysts. In this paper it is shown that chemical oxidants can be used to probe oxygen evolution activity for nickel‐based systems, and trends are reported that can improve future ligand design. Interestingly, different ligand effects were observed in comparison to other first‐row transition metal complexes. For example, nickel complexes with secondary amine donors were more active than with tertiary amine donors, which is the opposite for iron complexes. The incorporation of imine donor groups in a cyclam ligand resulted in the fastest and most durable nickel catalyst of our series, achieving oxygen evolution turnover numbers up to 380 and turnover frequencies up to 68 min−1 in a pH 5.0 acetate buffer using Oxone as oxidant. Initial kinetic experiments with this catalyst revealed a first order in chemical oxidant and a half order in catalyst. This implies a rate‐determining oxidation step from a dimeric species that needs to break up to generate the active catalyst. These findings lay the foundation for the rational design of molecular nickel catalysts for water oxidation and highlight that catalyst design rules are not generally applicable for different metals. The odd one out: Trends in oxygen evolution activity of nickel complexes are revealed using Oxone as chemical oxidant, showing that there are different design rules for these nickel complexes than for other first‐row transition metals. A cyclam‐like complex with imine donor groups is most active, reaching a turnover number of up to 380 and a turnover frequency of 68 min−1. Kinetic studies indicate a rate‐determining oxidation step, which is preceded by the breakup of a dormant nickel dimer. |
| Databáze: | OpenAIRE |
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