Effect of Ligand Chelation and Sacrificial Oxidant on the Integrity of Triazole-Based Carbene Iridium Water Oxidation Catalysts

Mazloomi, Zahra; Margalef, Jessica; Gil-Sepulcre, Marcos; Romero, Nuria; Albrecht, Martin; Llobet, Antoni; Sala, Xavier; Pàmies, Oscar; Diéguez, Montserrat (2020). Effect of Ligand Chelation and Sacrificial Oxidant on the Integrity of Triazole-Based Carbene Iridium Water Oxidation Catalysts. Inorganic chemistry, 59(17), pp. 12337-12347. American Chemical Society 10.1021/acs.inorgchem.0c01439

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We report the effect of replacing the pyridine group in the chelating trz Ir–water oxidation catalysts by a benzoxazole and a thiazole moiety. We have also evaluated if the presence of bidentate ligands is crucial for high activities and to avoid the decomposition into undesired heterogeneous layers. The catalytic performance of these benzoxazole/thiazole–triazolidene Ir-complexes in water oxidation was studied at variable pH using either CAN (pH = 1) or NaIO4 (pH = 5.6 and 7). Electrocatalytic experiments indicated that while CAN-mediated water oxidation led to catalyst heterogeneization irrespective of the triazolylidene substituent, periodate as sacrificial oxidant preserved a homogeneously active species. Repetitive additions of sacrificial oxidant indicates higher integrity of the Ir-complex with a thiazole-substituted triazolylidene compared to ligands featuring a benzoxazole as chelating donor or no chelating group at all. Rigid chelation of the thiazole group was also established from stability measurements under highly acidic, oxidizing, and high ionic strength conditions.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Albrecht, Martin

Subjects:

500 Science > 540 Chemistry

ISSN:

0020-1669

Publisher:

American Chemical Society

Funders:

[18] European Research Council ; [42] Schweizerischer Nationalfonds

Projects:

[1134] Exploiting Synergistic Properties of Mesoionic Carbene Complexes: Teaching Rusty Metals Challenging Catalysis
[1283] Designer ligands for oxidative bond activation catalysis

Language:

English

Submitter:

Eik Szee Goh Aschauer

Date Deposited:

02 Feb 2021 16:50

Last Modified:

02 Feb 2021 16:50

Publisher DOI:

10.1021/acs.inorgchem.0c01439

BORIS DOI:

10.48350/151060

URI:

https://boris.unibe.ch/id/eprint/151060

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