Release Time:2019-03-12  Hits:

Indexed by: Journal Article

Date of Publication: 2017-09-01

Journal: COORDINATION CHEMISTRY REVIEWS

Included Journals: Scopus、SCIE

Volume: 346

Issue: ,SI

Page Number: 206-215

ISSN: 0010-8545

Key Words: Water oxidation; EPR; Ruthenium; Coordination; DFT

Abstract: The coordination of a substrate water molecule on a metal centered catalyst for water oxidation is a crucial step involving the reorganization of the ligand sphere. This process can occur by substituting a coordinated ligand with a water molecule or via a direct coordination of water onto an open site. In 2009, we reported an efficient ruthenium-based molecular catalyst, Ru-bda, for water oxidation. Despite the impressive improvement in catalytic activity of this type of catalyst over the past years, a lack of understanding of the water coordination still remains. Herein, we report our EPR and DFT studies on Ru-bda (triethylammonium 3-pyridine sulfonate)(2) (1) at its Ru-III oxidation state, which is the initial state in the catalytic cycle for the O-O bond formation. Our investigation suggests that at this III-state, there is already a rearrangement in the ligand sphere where the coordination of a water molecule at the 7th position (open site) takes place under acidic conditions (pH = 1.0) to form a rare 7-coordinated Ru-III species. (C) 2017 Elsevier B.V. All rights reserved.