Synthesis and luminescence of ruthenium tris(2,2′-bipyridine)–zirconium phosphates

Abstract

Three adducts of Ru(bpy)²⁺₃ with zirconium phosphates have been synthesized. The crystalline intercalate, Ru(bpy)²⁺₃–HZrP, where a maximum of 25% of the interlamellar protons of α-HZrP are replaced by Ru(bpy)²⁺₃, has its emission maximum at ca. 615 nm. By ion exchange or impregnation of Ru(bpy)²⁺₃ on zirconium phosphate the complex is adsorbed only on the external surface. A similar material is prepared by reflux in the presence of very small amounts of Ru(bpy)²⁺₃. These materials have their emission maximum at 640–5 nm. When Ru(bpy)₃Cl₂, ZrOCl₂·8H₂O and H₃PO₄ are refluxed a species is formed which emits at 590 nm when excited at 420 nm. Its diffuse reflectance spectrum has a weak band at 32000 cm^–1 due to protonated bipyridine and a weak, broad band at 10 200 cm^–1 of unknown origin. The emission intensities vary with Ru(bpy)²⁺₃ loading in a characteristic way for the adducts synthesized.