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Syntheses, spectroscopic and molecular quadratic nonlinear optical properties of dipolar ruthenium(II) complexes of the ligand 1,2-phenylenebis(dimethylarsine)

Coe, Benjamin J. and Harries, Josephine L. and Harris, James A. and Brunschwig, Bruce S. and Coles, Simon J. and Light, Mark E. and Hursthouse, Michael B. (2004) Syntheses, spectroscopic and molecular quadratic nonlinear optical properties of dipolar ruthenium(II) complexes of the ligand 1,2-phenylenebis(dimethylarsine). Dalton Transactions, 2004 (18). pp. 2935-2942. ISSN 1477-9226. http://resolver.caltech.edu/CaltechAUTHORS:20110920-072807980

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Abstract

Six new complex salts trans-[Ru^(II)Cl(pdma)_2L][PF_6]_n [pdma = 1,2-phenylenebis(dimethylarsine); L = (E,E,E)-1,6-bis(4-pyridyl)hexa-1,3,5-triene (bph), n = 1, 5; L = N-methyl-4-[(E)-2-(4-pyridyl)ethenyl]pyridinium (Mebpe^+), n = 2, 7; L = N-methyl-4-[(E,E)-4-(4-pyridyl)buta-1,3-dienyl]pyridinium (Mebpb^+), n = 2, 8; L = N-methyl-4-{(E,E,E)-6-(4-pyridyl)hexa-1,3,5-trienyl}pyridinium (Mebph^+), n = 2, 9; L = bis(4-pyridyl)acetylene (bpa), n = 1, 10; L = N-methyl-4-[2-(4-pyridyl)ethynyl]pyridinium (Mebpa^+), n = 2, 11] have been prepared. The electronic absorption spectra of 5 and 7–11 display intense, visible metal-to-ligand charge-transfer (MLCT) bands, with λ_(max) values in the range 434–492 nm in acetonitrile. Cyclic voltammetric studies reveal reversible Ru^(III/II) waves with E_(1/2) values in the range 1.06–1.15 V vs. Ag–AgCl, together with irreversible L-based reduction processes. Along with a number of previously reported related compounds (B. J. Coe et al., J. Chem. Soc., Dalton Trans., 1996, 3917; 1997, 591; 2000, 797), salts 5 and 7–11 have been investigated by using Stark (electroabsorption) spectroscopy in butyronitrile glasses at 77 K. These studies have afforded dipole moment changes Δμ_(12) for the MLCT transitions which have been used to calculate molecular static first hyperpolarizabilities β_0 according to the two-state equation β_0 = 3Δμ_(12)(μ_(12))^2/(E_(max))^2 (μ_(12) = transition dipole moment, E_(max) = MLCT energy). MLCT absorption and electrochemical data show that a trans-{Ru^(II)Cl(pdma)_2}^+ centre is considerably less electron-rich than a {Ru_(II)(NH_3)_5}^(2+) unit. Although the β_0 responses of the pdma complexes are only a little smaller than those of their {Ru_(II)(NH_3)_5}^(2+) analogues, this result is partly attributable to unexpected changes in the relative μ_(12) values on freezing. Thus, substantial increases in μ_(12) for the arsine compounds act to partially offset the β_0-decreasing influence of their higher E_(max) values when compared with the analogous pentaammine species. Single crystal X-ray structures have been obtained for the salts 1·2.5MeCN, 4·2MeCN, 7 and 11, but only 1·2.5MeCN adopts a non-centrosymmetric space group (Fdd2) such as may show bulk NLO effects.


Item Type:Article
Related URLs:
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http://dx.doi.org/10.1039/B409432HDOIUNSPECIFIED
http://pubs.rsc.org/en/Content/ArticleLanding/2004/DT/b409432hPublisherUNSPECIFIED
Additional Information:© 2004 Royal Society of Chemistry. Received 21 June 2004, Accepted 29 July 2004. First published as an Advance Article on the web 24th August 2004. We thank the EPSRC for support (a PhD studentship and grant GR/M93864), and are also grateful to Dr Lathe A. Jones for the improved synthesis of bis(4-pyridyl)acetylene (bpa).
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EPSRCGR/M93864
Record Number:CaltechAUTHORS:20110920-072807980
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20110920-072807980
Official Citation:Syntheses, spectroscopic and molecular quadratic nonlinear optical properties of dipolar ruthenium(II) complexes of the ligand 1,2-phenylenebis(dimethylarsine) Benjamin J. Coe, Josephine L. Harries, James A. Harris, Bruce S. Brunschwig, Simon J. Coles, Mark E. Light and Michael B. Hursthouse Dalton Trans., 2004, 2935-2942 DOI: 10.1039/B409432H
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:25362
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:20 Sep 2011 18:21
Last Modified:26 Dec 2012 13:41

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