Issue 43, 2013

Bis(4′-(4-pyridyl)-2,2′:6′,2′′-terpyridine)ruthenium(ii) complexes and their N-alkylated derivatives in catalytic light-driven water oxidation

Abstract

Hydrogen sulfate salts of [Ru(1)2]2+ where 1 = 4′-(4-pyridyl)-2,2′:6′,2′′-terpyridine and four N-alkylated derivatives [Ru(L)2]4+ were used as photosensitizers (λmax ∼510 nm) for water oxidation in light driven reactions with peroxydisulfate as a sacrificial electron acceptor and Na10[Co4(H2O)2(α-PW9O34)2] (Co4POM) as the catalyst in sodium borate buffers at pH 8.0 and 9.0. The N-substituents investigated were benzyl (L+ = 2+), ethyl (L+ = 3+), allyl (L+ = 4+) and 4-cyanobenzyl (L+ = 5+). The O2 yield in the presence of [Ru(L)2]4+ (L+ = 2+–4+) was comparable to that obtained in the presence [Ru(bpy)3]2+ (bpy = 2,2′-bipyridine) using light sources with λmax ≈ 490 nm. The ruthenium(III) complexes [Ru(1)2]3+ and [Ru(L)2]5+ (L+ = 2+–5+) are rather unstable in acidic conditions and could not be isolated. The most efficient photosensitizers [Ru(L)2]5+ (L+ = 2+ and 4+) were the least stable under weakly basic conditions (pH 9.0) with a half-life τ1/2 ∼ 10 ms. The stability of the complexes under photocatalytic turnover conditions is probably controlled by the rate at which ligand L+ is oxidized by Co4POM in its highest oxidation state.

Graphical abstract: Bis(4′-(4-pyridyl)-2,2′:6′,2′′-terpyridine)ruthenium(ii) complexes and their N-alkylated derivatives in catalytic light-driven water oxidation

Article information

Article type
Paper
Submitted
24 Apr 2013
Accepted
19 Aug 2013
First published
11 Sep 2013
This article is Open Access
Creative Commons BY license

RSC Adv., 2013,3, 20647-20654

Bis(4′-(4-pyridyl)-2,2′:6′,2′′-terpyridine)ruthenium(II) complexes and their N-alkylated derivatives in catalytic light-driven water oxidation

H. Lv, J. A. Rudd, P. F. Zhuk, J. Y. Lee, E. C. Constable, C. E. Housecroft, C. L. Hill, D. G. Musaev and Y. V. Geletii, RSC Adv., 2013, 3, 20647 DOI: 10.1039/C3RA44192J

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