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

(Figure Presented) The syntheses of cationic ruthenium(II) complexes [Ru(Me₂-bpy)(PPh₃)₂RR][PF₆]_x {Me₂-bpy = 4,4′-dimethyl-2,2′-bipyridine, (3) R′ = Cl, R′ = N≡CMe, x = 1, (4) R = Cl, R′ = N≡CPh, x = 1, (5) R = R′ = N≡CMe, x = 2} and [Ru(Me₂-bpy)(κ²-dppf)RR][PF₆]_x {dppf = 1,1′-bis(diphenylphosphino)ferrocene, (6) R = Cl, R′ = N≡CMe, x = 1, (7) R = Cl, R′ = N≡CPh, x = 1, (8) R = R′ = 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 trans-[Ru(Me₂-bpy)(PPh₃)₂(N≡CCH₃)Cl][PF₆] (3), by X-ray crystallography. Electronic absorption and emission spectra of the complexes reveal that all complexes except 4 and 6 are emissive in the range 370-400 nm with 8 exhibiting an emission in the blue. Cyclic voltammetry studies of 3-8 show reversible or quasi-reversible redox processes at ca. 1 V, assigned to the Ru(II/III) couple.