Synthesis and Excited-State Properties of a Novel Ruthenium Nucleoside: 5-[Ru(bpy)₂(4-m-4‘-pa-bpy)]²⁺-2‘-deoxyuridine

Abstract

The synthesis and photophysical properties of a novel ruthenium-modified nucleoside 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 propargylamine-derivatized Ru(bpy)32+ and 3‘,5‘-dibenzoyloxy-2‘-deoxy-5-iodouridine. The long-lived 3MLCT excited state (1300 ns) of 5-[Ru(bpy)2(4-m-4‘-pa-bpy)]2+-2‘-deoxyuridine has an emission maximum centered at 640 nm. Step-scan Fourier transform infrared (S2FTIR) time-resolved spectroscopy reveals the excited-state electron to be localized on the modified bipyridine with the excited-state dipole oriented toward the 2‘-deoxyuridine.