A mononuclear ruthenium complex [Ru(bpy)(2)(bpp)](PF6) (1) and its halogenated and nitro derivatives [Ru(bpy)(2)(Xbpp)](PF6) (bpy = 2,2'-bipyridine; bpp = 3,5-bis(2-pyridyl)pyrazole; X = Cl, 2; X = Br, 3; X = I, 4; X = NO2, 5) have been synthesized and characterized by H-1 NMR, C-13 NMR, HRMS, elemental analysis. Complexes 2-5 have been further confirmed by X-ray diffraction. Their UV-Vis and emission spectroscopies, electrochemical measurements and acid-base properties are described. The results presented here reveal that the introduction of Cl, Br, I and NO2 groups to the coordinated bpp(-) ligand makes the absorption and emission maxima of the parent complex 1 blue-shifted, the oxidation potential of the Ru-II/Ru-III couple increased and the pK(a) value decreased obviously. In addition, significant quenching of the emission by these groups is also observed.
2008. Vol. 27, no 4, 1168-1176 p.