Reactivity of [{(η⁶<i>-p-cymene)</i>RuCl(μ-Cl)}₂] towards some N-heterocyclics and tertiary phosphines

Abstract

Reactions of [{(η⁶<i>-p-cymene)</i>RuCl(μ-Cl)}₂] with anthranilic acid (aa), pyrazole, 3-methylpyrazole, 3,5- dimethylpyrazole, indazole, imidazole, benzimidazole and tertiary phosphines have been carried out to give complexes with the formula [{(η⁶<i>-p-cymene)</i>Ru (aa)Cl], [{(η⁶<i>-p-cymene)</i>Ru (aa)L] and [{(η⁶<i>-p-cymene)</i>Ru(aa)L']BF₄. The anthranilic acid behaves in a chelating bidentate N, O-bonded mode. Further, chloride substitution takes place with azole derivatives and tertiary phosphines to produce the neutral and cationic complexes, respectively. The complexes have been characterised on the basis of elemental analyses, conductance measurements, IR, ¹H, ¹³C and ³¹P NMR and electronic spectral data and probable structures have been proposed. Redox behaviour of these complexes was also studied by cyclic voltammograms. An irreversible single reduction wave for Ru(II) to Ru(0) ranging from -0.5 - -1.4 volts has been observed, which indicates a single step two electron process.