In:
European Journal of Inorganic Chemistry, Wiley, Vol. 26, No. 3 ( 2023-01-13)
Abstract:
Two mononuclear ruthenium(II) complexes based on dianionic {N 4 } ligands and with axial pyridines have been prepared and characterized crystallographically ( 1 ) or by 2D NMR spectroscopy using residual dipolar couplings ( 2 ). The {N 4 } ligands provide a constrained equatorial coordination with one large N−Ru−N angle, and additional non‐coordinating N atoms in case of 2 . Their redox properties have been investigated (spectro)electrochemically, and their potential to serve as water oxidation catalysts has been probed using cerium ammonium nitrate (CAN) at pH 1.0. Complex 1 undergoes rapid degradation, likely via ligand oxidation, whereas 2 is more rugged and exhibits 80 % efficiency in the Ce IV ‐driven water oxidation, with a high initial turnover frequency (TOF i ) of 3.07×10 −2 s −1 (at 100 equiv. CAN). The initial rate of O 2 evolution exhibits 1 st order dependence on catalyst concentration, suggesting a water nucleophilic attack mechanism. Repeated addition of CAN and control experiments show that high ionic strength conditions (both NO 3 − and Ce III ) significantly decrease the TOF.
Type of Medium:
Online Resource
ISSN:
1434-1948
,
1099-0682
DOI:
10.1002/ejic.202200597
Language:
English
Publisher:
Wiley
Publication Date:
2023
detail.hit.zdb_id:
1475009-0
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