SYNTHESIS AND CHARACTERIZATION OF [(BPY)2RUII(1,3-ME2LUMAZINE)](PF6)2

The complex [(bpy)2Ru(II)(1,3-Me2Lum)](PF6)2 (where bpy = 2,2'-bipyridine and 1,3-Me2Lum = 1,3-dimethyllumazine) has been prepared. Infrared and elemental analyses show that Ru(II) binds 1,3-Me2Lum through the N-5 and O-4 positions on the ligand. Cyclic voltammetry in CH3CN reveals a nearly reversible wave (DELTA-E(p) = 70 mV) for the complex centered at E1/2 = + 1.33 V (versus SSCE). The reduction potential (in CH3CN) for the coordinated 1,3-Me2Lum is shifted by + 0.800 V relative to that of the free ligand. In water, the complex showed pH-independent (pH = 4.26-9.12) irreversible oxidative waves at approximately + 1.2 V. Reductive scans in water gave results that were qualitatively similar to those obtained in CH3CN. UV-Vis analysis in CH3CN showed bpy (pi --> pi*) bands at 242 and 285 nm, 1,3-Me2Lum absorptions around 350-365 nm, and fairly intense MLCT bands centered at 431 and 509 nm.