Synthesis, structural, electrochemical, and spectroscopic studies of some (diimine)ruthenium nitrile complexes

The syntheses of cationic ruthenium(II) complexes [Ru(Me₂-bpy)(PPh₃)₂RRʹ][PF₆]_x {Me₂-bpy = 4,4ʹ-dimethyl-2,2ʹ-bipyridine, (<b>3</b>) R = Cl, Rʹ = N≡CMe, x = 1, (<b>4</b>) R = Cl, Rʹ = N≡CPh, x = 1, (<b>5</b>) R = Rʹ = N≡CMe, x = 2} and [Ru(Me₂-bpy)(<i>κ</i>²-dppf)RRʹ][PF₆]_x {dppf = 1,1ʹ-bis(diphenylphosphino)ferrocene, (<b>6</b>) R = Cl, Rʹ = N≡CMe, x = 1, (<b>7</b>) R = Cl, Rʹ = N≡CPh, x = 1, (<b>8</b>) R = Rʹ = N≡CMe, x = 2} are reported, together with their structural confirmation by NMR (³¹P, ¹H) and IR spectroscopy and elemental analysis, and, in the case of <i>trans</i>-[Ru(Me₂-bpy)(PPh₃)₂(N≡CCH₃)Cl][PF₆] (<b>3</b>), by X-ray crystallography. Electronic absorption and emission spectra of the complexes reveal that all complexes except <b>4</b> and <b>6</b> are emissive in the range 370–400 nm with <b>8</b> exhibiting an emission in the blue. Cyclic voltammetry studies of <b>3–8</b> show reversible or quasi-reversible redox processes at <i>ca.</i> 1 V, assigned to the Ru(II/III) couple.