Synthesis, structure and redox behaviour of tethered arene–ruthenium(II) complexes

Tethered arene–ruthenium complexes [RuCl2{η1:η6-Me2P(CH2)3C6H5}], [RuCl2{η1:η6-Ph2PCH2SiMe2C6H5}] and [RuCl2{η1:η6-Ph2P(CH2)3(aryl)}] (aryl=2,4,6-C6H2Me3, C6Me5) have been prepared by thermal displacement of methyl o-toluate from the appropriate P-donor derivatives of [RuCl2(η6-1,2-MeC6H4CO2Me)]2 and their structures determined by X-ray studies. The tethered complexes undergo reversible one-electron oxidation by cyclic voltammetry; the half-wave potentials are in the range 1.10–1.34 V versus Ag ∣ AgCl and decrease with increasing methyl substitution on the arene.