Self-Assembled Monolayers Based Upon a Zirconium Phosphate Platform

Organically surface-modified alpha-zirconium phosphate was obtained by reacting the surface P-O-H groups of alpha-zirconium phosphate nanoparticles (alpha-ZrP) with octadecyltrichlorosilane (OTS). Surface functionalization of alpha-ZrP with OTS was accomplished using a one-step synthesis producing highly hydrophobic nanoparticles. The formation of P-O-Si bonds arising from nucleophilic attack of POH to the silane was confirmed by solid-state NMR experiments. The surface coverage of the organic modifier was characterized by TGA, AFM, and FTIR. In addition, we show the applicability of this system with a photoinduced electron-transfer reaction in a nonpolar solvent. Using an organically surface-modified alpha-ZrP previously loaded with tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)), the quenching of the luminescence of Ru(bpy)(3)(2+) in the presence of p-benzoquinone was monitored; a static quenching constant (K-s) value of 8.82 X 10(2) M-1 and a dynamic quenching constant (K-D) value of 6.99 X 10(2) M-1 were obtained.