Reactions of benzene–ruthenium(II) complexes with pyrazoles. Possible formation of amidine complexes [Ru(η-C6H6){NHCMe(R2pz)}(R2Hpz)]2+(R = H or Me, Hpz = pyrazole)

Abstract

In acetonitrile [{Ru(η-C₆H₆)Cl₂}₂] reacted with pyrazole (Hpz), 3,5-dimethylpyrazole (Me₂Hpz), or with K[HB(Me₂pz)₃] to give products assigned as the amidine complexes [Ru(η-C₆H₆){NHCMe(R₂pz)}(R₂Hpz)]²⁺(R = H or Me). In methanol, reactions with pyrazoles afforded [Ru(η-C₆H₆)Cl(R₂Hpz)₂]⁺(R = H or Me), but in benzene only [Ru(η-C₆H₆)Cl₂(Me₂Hpz)] was formed. The complexes were characterised on the basis of spectroscopic studies.