Synthesis and excited-state properties of a novel ruthenium nucleoside: 5-[Ru(bpy)(2)(4-m-4 '-pa-bpy)](2+)-2 '-deoxyuridine

The synthesis and photophysical properties of a novel ruthenium-modified nu cleoside are reported. The key synthetic step to 5-[Ru(bpy)2(4-m-4'-pa-bpy) ](2+)-2'-deoxyuridine involves the Pd(0)-catalyzed cross-coupling of a prop argylamine-derivatized Ru(bpy)(3)(2+) and 3',5'-dibenzoyloxy-2'-deoxy-5-iod ouridine. The long-lived (MLCT)-M-3 excited state (1300 ns) of 5-[Ru(bpy)(2 )(4-m-4'-pa-bpy)](2+)-2'-deoxyuridine has an emission maximum centered at 6 40 nm.; Step-scan Fourier transform infrared ((SFTIR)-F-2) time-resolved sp ectroscopy reveals the excited-state electron to be localized on the modifi ed bipyridine with the excited-state dipole oriented toward the 2'-deoxyuri dine.