Bhattacharyya, Indranil ; Shivakumar, Maya ; Chakravorty, Animesh (2002) Chemistry of a family of semiquinone monochelates of carbonyl ruthenium(II) generated by reacting quinones with hydridic species Polyhedron, 21 (27-28). pp. 2761-2765. ISSN 0277-5387
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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S02775...
Related URL: http://dx.doi.org/10.1016/S0277-5387(02)01281-0
Abstract
The reactions of [Ru(H)(Cl)(CO)(PPh3)3] with 3,5-di-tert-butyl-o-benzoquinone (dbq) and 3,4,5,6-tetrachloro-o-benzoquinone (tcq) have afforded the corresponding semiquinone complexes [RuII(dbsq)(Cl)(CO)(PPh3)2] and [RuII(tcsq)(Cl)(CO)(PPh3)2], respectively. The reaction of [Ru(H)2(CO)(PPh3)3] with tcq has furnished [RuII(tcsq)(H)(CO)(PPh3)2]. Structure determination of [Ru(dbsq)(Cl)(CO)(PPh3)2] has revealed that it is a model semiquinonoid chelate with two equal C---O lengths ( 1.291(6) and 1.296(6) Å). The complexes are one-electron paramagnetic (~1.85μB) and their EPR spectra in fluid media display a triplet structure (g~2.00) due to superhyperfine oupling with two trans-31P atoms (Aiso~17 G). The stretching frequency of the CO ligand increases by 20 cm-1 in going from [Ru(dbsq)(Cl)(CO)(PPh3)2] to [Ru(tcsq)(Cl)(CO)(PPh3)2] consistent with electron withdrawal by chloro substituents. For the same reason the E1/2 values of the cyclic voltammetric quinone/semiquinone and semiquinone/catechol couples undergo a shift of ~500 mV to higher potentials between [Ru(dbsq)(Cl)(CO)(PPh3)2] and [Ru(tcsq)(Cl)(CO)(PPh3)2].
| Item Type: | Article |
|---|---|
| Source: | Copyright of this article belongs to Elsevier Science. |
| Keywords: | Ruthenium(II) Complexes; Semiquinone Monochelates; Homolytic Hydride Cleavage |
| ID Code: | 6847 |
| Deposited On: | 26 Oct 2010 05:23 |
| Last Modified: | 31 Jan 2011 05:38 |
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