188679-91-6Relevant articles and documents
Synthesis, crystal structures, and electrochemical and spectroscopic properties of ruthenium complexes of the N,S-bidentate ligand 2-(2-pyriyl)benzenethiol
Thompson, Alexander M. W. Cargill,Bardwell, David A.,Jeffery, John C.,Rees, Leigh H.,Ward, Michael D.
, p. 721 - 726 (2007/10/03)
Conversion of the amino group of 2-(2-aminophenyl)pyridine into a thiol to give the N,S-donor chelating ligand 2-(2-pyridyl)benzenethiol (HL) afforded the oxidised disulfide L-L which was crystallographically characterised.It shows an interesting example of an intermolecular N...S-S interaction (N...S distances are 2.778 and 2.724 Angstroem; N...S-S angles are both ca. 11 deg) in which the pyridyl lone pair interacts weakly with the ?* orbital of the S-S bond.Reaction of L-L with *2H2O (bipy=2,2'-bipyridine) and RuCl3*xH2O afforded II(bipy)2L> 1 and IIIL3> 2 respectively (following in situ reduction of the disulfide) which have N5S and mer-N3S3 donor sets respectively (N of pyridyl, S of benzenethiolate).Both were crystallographically characterised and have the expected pseudo-octahedral geometries.An interesting feature of both structures is that the relatively large Ru-S distances (compared to the Ru-N) prevent the pyridyl rings from approaching the metal centre as closely as they would if they were not constrained, so the Ru-N distances are longer than usual.Electrochemical studies show that the benzenethiolate ligands are more effective electron donors to ruthenium (both +2 and +3) than are phenolates: for example, the RuII-RuIII couple of 1 is at -0.07 V vs. ferrocene-ferrocenium, whereas the same couple of 2 was at -0.21 V, compared to +0.14 V for the N3O3-co-ordinated analogue.Complex 2 also shows a reversible ligand-based oxidation which is absent for 1, arising from stabilization of the sulfur-based radical cation by interaction with the lone pair on an adjacent sulfur atom in the co-ordination sphere of the complex, which cannot happen for 1.Electronic spectral properties show that the sulfur donor of 1 weakens the ligand field with respect to 2+, and that 2 has an intense sulfur-to-RuIII ligand-to-metal charge-transfer band.
