Synthesis, structure, and characterization of two polyoxometalate–photosensitizer hybrid materials

Two hybrid materials based on the tris(bipyridine)ruthenium(II), [Ru(bpy)3]2+ and Keggin-type polyoxometalates, [PW11O39]7− and [PW12O40]3−, namely, [Ru(bpy)3][K5PW11O39] (1) and [Ru(bpy)3][KPW12O40] (2) were synthesized. X-ray crystallographic study of the red-colored complex, 2, shows that it crystallizes in the orthorhombic space group Pbcn and the polyanions are associated with the [Ru(bpy)3]2+ counterions by Coulombic forces and supramolecular interactions. The molecular complex is further connected and forms a three-dimensional framework through C–H⋯OPOM and other weak interactions. These complexes were further characterized by FT-IR, UV–Vis, 1H and 31P NMR, luminescent spectra and computational studies. Significantly, these combined spectroscopic studies show that these polyoxometalate–dye hybrids have strong electronic interactions between the cationic dye and polyanion units.