Kulkarni, Mukula S. ; Rao, B. S. Madhava ; Sastri, C. V. ; Maiya, Bhaskar G. ; Mohan, Hari ; Mittal, Jai P. (2004) Redox chemistry of Ru(II) complexes of 6,7-dicyanodipyridoquinoxaline: a radiation chemical study Journal of Photochemistry and Photobiology A: Chemistry, 167 (2-3). pp. 101-109. ISSN 1010-6030
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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S10106...
Related URL: http://dx.doi.org/10.1016/j.jphotochem.2004.04.001
Abstract
The reactions of √ OH, O√ -, SO4√ -, N3√ and eaq- with the ligands-1,10-phenanthroline (phen) and 6,7-dicyanodipyrido [2,2-d:2',3'-f] quinoxaline (dicnq) and a series of their Ru(II) complexes ([Ru(phen)3]2+, [Ru(phen)2(dicnq)]2+, [Ru(phen)(dicnq)2]2+ and [Ru(dicnq)3]2+) have been studied by pulse radiolysis with optical detection. The √ OH and hydrated electron react with the ligands via adduct formation with diffusion controlled rates. The transient spectra obtained in the reactions of √ OH with phen has two peaks (350 and 430 nm) having nearly equal intensities and a broad maximum at 380 nm with dicnq. In the case of complexes, the rate constants for the reactions of √ OH and eaq- are in the range (7.5-11.8)× 109 and (1.6-3.1)× 1010 dm3 mol-1 s-1, respectively. The rate for the √ OH reaction increased with the dicnq content in the complex, whereas a reverse trend was seen in the hydrated electron reaction. Neither the ligand nor the Ru(II) complex except [Ru(phen)2(dicnq)]2+ is reactive toward the azide radical. In the reaction of √ OH with Ru(II) complexes, the transients have absorption maxima in the range of 380-435 nm whose intensity decreased with the dicnq content. The spectra measured in the reactions of √ OH and one electron oxidants (Cl2√ -, SO4√ - or N3√ ) with the complexes are not identical unlike with ligands. The reaction mechanism involves the addition of vOH and eaq- to the ligands of the complexes and the conversion of Ru(II)-Ru(III) by the one electron oxidant.
Item Type: | Article |
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Source: | Copyright of this article belongs to Elsevier Science. |
Keywords: | Pulse Radiolysis; Ru(II) Complex; Quinoxaline; Phenanthroline |
ID Code: | 25693 |
Deposited On: | 04 Dec 2010 11:53 |
Last Modified: | 17 Jul 2012 05:17 |
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