Issue 22, 1995

Dinuclear ruthenium(II) and/or osmium(II) complexes of a non-symmetric bis-chelating quaterpyridine ligand. Synthesis, electrochemical behaviour, absorption spectra, luminescence properties and intercomponent energy transfer

Abstract

We have synthesized the hexafluorophosphate salts of the mono- and di-nuclear compounds Ru–LL′, Os–LL′, Ru–LL′–Ru, Os–LL′–Os, Ru–LL′–Os and Os–LL′–Ru, where Ru and Os are {Ru(bipy)2}2+ and {Os(bipy)2}2+ fragments (bipy = 2,2′-bipyridine), and LL′ is the bis-chelating 2,2′ : 3′,2″:6″,2‴- quaterpyridine bridging ligand with inequivalent bipy-type binding sites (L and L′). The compound [(bipy)2Os(LL′)Ru(bipy)2][PF6]4·3MeCN has been crystallographically characterized, the co-ordination environment about the OsII centre is essentially identical to that of [Os(bipy)3]2+, but the co-ordination environment about the RuII centre is somewhat distorted with one particularly long Ru–N bond, due to the inherent sterically hindered nature of the L′ site of the bridging ligand. Electrochemical studies show that a given metal ion is slightly easier to oxidize when in the L co-ordination site, but the difference in the properties of the two moieties of the LL′ bridging ligand is much smaller than difference in the properties of RuII and OsII, so that in the mixed-metal complexes Ru–LL′–Os and the metal easier to oxidize is always Os and the luminescent moiety is always the Os-based one. The lowest energy (luminescent) level in the homodinuclear compounds is located on the L co-ordination site. In Ru–LL′–Os and Os–LL′–Ru electronic energy transfer from the higher energy (Ru-based) to the lower energy (Os-based) moiety is very fast and 100% efficient.

Article information

Article type
Paper

J. Chem. Soc., Dalton Trans., 1995, 3601-3608

Dinuclear ruthenium(II) and/or osmium(II) complexes of a non-symmetric bis-chelating quaterpyridine ligand. Synthesis, electrochemical behaviour, absorption spectra, luminescence properties and intercomponent energy transfer

V. Balzani, D. A. Bardwell, F. Barigelletti, R. L. Cleary, M. Guardigli, J. C. Jeffery, T. Sovrani and M. D. Ward, J. Chem. Soc., Dalton Trans., 1995, 3601 DOI: 10.1039/DT9950003601

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements