Basulia, Falguni ; Das, Anjan Kumar ; Mostafa, Golam ; Peng, Shie-Ming ; Bhattacharya, Samaresh (2000) Chemistry of ruthenium with some phenolic ligands: synthesis, structure and redox properties Polyhedron, 19 (14). pp. 1663-1672. 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(00)00404-6
Abstract
Reaction of three phenolate ligands, viz. salicylaldehyde (HL1), 2-hydroxyacetophenone (HL2) and 2-hydroxynaphthylaldehyde (HL3), (abbreviated in general as HL, where H stands for the phenolic proton) with [Ru(PPh3)3Cl2] in 1¦1 mole ratio gives complexes of the type[Ru(PPh3)2(L)Cl2]. The structure of the [Ru(PPh3)2(L2)Cl2] complex has been solved by X-ray crystallography. The coordination sphere around ruthenium isO2P2Cl2 with a cis-trans-cis geometry, respectively. The [Ru(PPh3)2(L)Cl2] complexes are one-electron paramagnetic (low-spin d5, S=½) and show rhombic ESR spectra in 1¦1 dichloromethane-toluene solution at 77 K. In dichloromethane solution the [Ru(PPh3)2(L)Cl2] complexes show several intense LMCT transitions in the visible region. Reaction between the phenolic ligands and [Ru(PPh3)3Cl2] in 2¦1 mole ratio in the presence of a base affords the [Ru(PPh3)2(L)2] complexes in two isomeric forms. 1H NMR spectra of one isomer shows that it does not have any C2 symmetry and has the cis-cis-cis disposition of the three sets of donor atoms. 1H NMR spectra of the other isomer shows that it has C2 symmetry. The structure of the isomer of the [Ru(PPh3)2(L1)2] complex has been solved by X-ray crystallography. The coordination sphere around ruthenium is O4P2 with a cis-trans-cis disposition of the carbonylic oxygens, phenolate oxygens and phosphorus atoms, respectively. The [Ru(PPh3)2(L)2] complexes are diamagnetic (low-spin d6, S=O) and show intense MLCT transitions in the visible region. Cyclic voltammetry on the [Ru(PPh3)2(L)Cl2] complexes shows a ruthenium(III)---ruthenium(II) reduction near -0.3 V versus SCE and a ruthenium(III)---ruthenium(IV) oxidation in the range 1.08-1.24 V versus SCE. Cyclic voltammetry on both isomers of the [Ru(PPh3)2(L)2] complexes shows a ruthenium(II)---ruthenium(III) oxidation within 0.09-0.41 V versus SCE, followed by a ruthenium(III)-ruthenium(IV) oxidation within 1.31-1.52 V versus SCE.
| Item Type: | Article |
|---|---|
| Source: | Copyright of this article belongs to Elsevier Science. |
| Keywords: | Ruthenium; Phenolic Ligands; Synthesis; Structure; Redox Properties |
| ID Code: | 1916 |
| Deposited On: | 08 Oct 2010 11:31 |
| Last Modified: | 16 May 2016 12:58 |
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