Inorganic Chemistry, Vol.52, No.21, 12492-12501, 2013
Synthesis of Phosphonic Acid Derivatized Bipyridine Ligands and Their Ruthenium Complexes
Water-stable, surface-bound chromophores, catalysts, and assemblies are an essential element in dye-sensitized photoelectrosynthesis cells for the generation of solar fuels by water splitting and CO2 reduction to CO, other oxygenates, or hydrocarbons. Phosphonic acid derivatives provide a basis for stable chemical binding on metal oxide surfaces. We report here the efficient synthesis of 4,4'-bis(diethylphosphonomethyl)-2,2'-bipyridine and 4,4'-bis(diethylphosphonate)-2,2'-bipyridine, as well as the mono-, bis-, and tris-substituted ruthenium complexes, [Ru(bpy)(2)(Pbpy)](2+), [Ru(bpy)(Pbpy)(2)](2+), [Ru(Pbpy)(3)](2+), [Ru(bpy)(2)(CPbpy)](2+), [Ru(bpy)(CPbpy)(2)](2+), and [Ru(CPbpy)(3)](2+) [bpy = 2,2'-bipyridine; Pbpy = 4,4'-bis(phosphonic acid)-2,2'-bipyridine; CPbpy = 4,4'-bis(methylphosphonic acid)-2,2'-bipyridine].