Ruthenium-mediated selective cleavage of nitrogen–carbon bond of the diimine function. Synthesis, spectroscopic and redox properties of the complexes [Ru(L)2{−OC6H4C(CH3)=N―H}][ClO4] (L=2,2′-bipyridine and 1,10-phenanthroline) and the crystal structure of the bipyridine derivative
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Title |
Ruthenium-mediated selective cleavage of nitrogen–carbon bond of the diimine function. Synthesis, spectroscopic and redox properties of the complexes [Ru(L)2{−OC6H4C(CH3)=N―H}][ClO4] (L=2,2′-bipyridine and 1,10-phenanthroline) and the crystal structure of the bipyridine derivative
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Creator |
CHAKRABORTY, SOMA
WALAWALKAR, MRINALINI G LAHIRI, GOUTAM KUMAR |
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Subject |
crystal structure
redox properties spectroscopic properties |
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Description |
The reactions of Ru(bpy)2(CO3) (bpy=2,2′-bipyridine) and Ru(phen)2(CO3) (phen=1,10-phenanthroline) with the binucleating phenolato diimine function, OH―C6H4―C(CH3)=N―CH2―C6H4―CH2―N=(CH3)C―C6H4―OH, H2L in ethanol solvent under dinitrogen atmosphere result in ruthenium bipyridine/phenanthroline heterochelates [Ru(bpy)2/(phen)2L′](ClO4) 1 where L′ corresponds to the ketonic imine function −O―C6H4C(CH3)=N―H incorporating the rare 2 bonds on the lefthand sideC=N―H fragment. In the course of the reaction the N―C bond of the diimine function in H2L has been selectively cleaved. The formation of 1 has been authenticated by single-crystal X-ray structure of the bipyridine derivative (1a). The RuN5O coordination sphere is distorted octahedral. The diamagnetic complexes 1 exhibit 1:1 conductivity in acetonitrile solution. The complexes show strong RuII→π*(bpy)/(phen) MLCT transitions in the visible region and intra-ligand transitions in the UV region. The complexes exhibit moderately strong emissions near 700 nm from the lowest energy MLCT bands (Φ=1.7–2.2×10−2). The complexes (1a and 1b) display reversible ruthenium(III)–ruthenium(II) couple near 0.5 V, irreversible ruthenium(III)→ruthenium(IV) oxidation near 1.7 V and one ligand-based (L′) oxidation near 2.0 V versus SCE. The reductions of the bpy and phen ligands have been observed at the negative side of SCE. The electrochemically oxidized ruthenium(III) complexes (1a+ and 1b+) are found to be unstable at 298 K and exhibit rhombic EPR spectra having three distinct g values corresponding to the trivalent ruthenium(III) under distorted octahedral arrangement. The oxidized complexes (1a+ and 1b+) exhibit LMCT transitions near 750 nm.
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Publisher |
Elsevier
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Date |
2009-04-03T09:03:10Z
2011-11-25T20:32:00Z 2011-12-26T13:08:14Z 2011-12-27T05:56:14Z 2009-04-03T09:03:10Z 2011-11-25T20:32:00Z 2011-12-26T13:08:14Z 2011-12-27T05:56:14Z 2001 |
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Type |
Article
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Identifier |
Polyhedron 20(15-16), 1851-1858
0277-5387 http://dx.doi.org/10.1016/S0277-5387(01)00751-3 http://hdl.handle.net/10054/1111 http://dspace.library.iitb.ac.in/xmlui/handle/10054/1111 |
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Language |
en
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