Jump to main content
Jump to site search

Issue 10, 2020
Previous Article Next Article

Ru(ii) water oxidation catalysts with 2,3-bis(2-pyridyl)pyrazine and tris(pyrazolyl)methane ligands: assembly of photo-active and catalytically active subunits in a dinuclear structure

Author affiliations

Abstract

Two mononuclear Ru(II) complexes, i.e. [RuCl(κ3N-terpy)(κ2N-dpp)]PF6 ([1]PF6; terpy = 2,2′:6′,2′′-terpyridine; dpp = 2,3-bis(2′-pyridyl-pyrazine) and [RuCl(κ3N-tpm)(κ2N-dpp)]Cl ([2]Cl; tpm = tris(1-pyrazolyl)methane), and one dinuclear complex, i.e. [Ru2Cl(κ3N-tpm)(μ-κ2N2N-dpp)Ru(κ2N-bpy)2][PF6]3 ([3][PF6]3; bpy = 2,2′-bipyridine), have been synthesized and their water oxidation catalytic properties have been investigated. A combined DFT and experimental (35Cl NMR and conductivity measurements) study aimed to elucidate the nature of [1]+ and [2]+ in aqueous solution has also been performed, indicating that one water molecule is allowed to enter the first coordination sphere of [2]+ in the ground state, replacing one tpm nitrogen. Conversely, in the case of [1]+, water coordination, assumed to be needed for the water oxidation process, presumably occurs following the oxidation of the metal. For all complexes, a catalytic wave has been detected in acetonitrile/water 1 : 1 (v/v) solution in the range 1.4–1.7 V vs. SCE. In all cases, water oxidation (investigated at pH < 8) takes place initially via a proton-coupled two-electron, two-proton process with the formation of an Ru(IV)[double bond, length as m-dash]O moiety, followed by one electron oxidation and water nucleophilic attack. The TON and TOF values (within the range of 16–33 and 1.3–2.2 h−1, respectively) of the complexes are higher than those of the benchmark [Ru(LLL)(LL)(OH2)]2+-type species (LLL and LL are tridentate and bidentate polypyridine ligands, respectively), which is [Ru(terpy)(bpm)(OH2)]2+.

Graphical abstract: Ru(ii) water oxidation catalysts with 2,3-bis(2-pyridyl)pyrazine and tris(pyrazolyl)methane ligands: assembly of photo-active and catalytically active subunits in a dinuclear structure

Back to tab navigation

Supplementary files

Article information


Submitted
19 Dec 2019
Accepted
13 Feb 2020
First published
13 Feb 2020

Dalton Trans., 2020,49, 3341-3352
Article type
Paper

Ru(II) water oxidation catalysts with 2,3-bis(2-pyridyl)pyrazine and tris(pyrazolyl)methane ligands: assembly of photo-active and catalytically active subunits in a dinuclear structure

A. de Palo, G. La Ganga, F. Nastasi, M. Guelfi, M. Bortoluzzi, G. Pampaloni, F. Puntoriero, S. Campagna and F. Marchetti, Dalton Trans., 2020, 49, 3341
DOI: 10.1039/C9DT04815D

Social activity

Search articles by author

Spotlight

Advertisements