Enhanced stable luminescence and photochemical properties of ruthenium complex/zirconium phosphate hybrid assemblies

The luminescent metal complex Ru(bpy)3Cl2.6H2O was directly intercalated into Zr(HPO4)2.6H2O nano-lamellar framework and characterized with respect to its optical and photochemical properties. The incorporation of the complex within the inorganic framework expands the interlayer distance from 10.4 to 15.2 A, and forms complex/framework hybrid assemblies. Upon binding to the framework, the metal-to-ligand charge transfer absorption of the complex is red-shifted from 452 to 462 nm, and the maximum emission is blue-shifted from 610 to 604 nm. The luminescence intensity of the complex/framework suspensions increases more than 2-fold as compared to aqueous solutions. The sub-micrometer (0.2-0.3 microm) particles of the hybrid assemblies result in the luminescence intensity of the suspensions quite stable. In addition, the excited state of Ru(bpy)3(2+) was photochemical quenched by Fe(CN)6(3-), and the Stern-Volmer results reveal that most Ru(bpy)3(2+) cations have entered into the layer of the framework.