Luminescence Rigidochromism and Redox Chemistry of Pyrazolate-Bridged Binuclear Platinum(II) Diimine Complex Intercalated into Zirconium Phosphate Layers

The direct intercalation of a pyrazolate-bridged platinum­(II) bipyridyl dimer ([{Pt­(dmbpy)­(μ-pz)}<sub>2</sub>]<sup>2+</sup>; dmbpy = 4,4′-dimethyl-2,2′-bipyridine, pz<sup>–</sup> = pyrazolate) within a zirconium phosphate (ZrP) framework has been accomplished. The physical and spectroscopic properties of [{Pt­(dmbpy)­(μ-pz)}<sub>2</sub>]<sup>2+</sup> intercalated in ZrP were investigated by X-ray powder diffraction and X-ray photoelectron, infrared, absorption, and luminescence spectroscopies. Zirconium phosphate layers have a special microenvironment that is capable of supporting a variety of platinum oxidation states. Diffuse reflectance spectra from powders of the blue-gray intercalated materials show the formation of a low-energy band at 600 nm that is not present in the platinum dimer salt. The nonintercalated complex is nonemissive in room-temperature fluid solution, but gives rise to intense blue-green emission in a 4:1 ethanol/methanol 77 K frozen glassy solution. Powders and colloidal suspensions of [{Pt­(dmbpy)­(μ-pz)}<sub>2</sub>]<sup>2+</sup>-exchanged ZrP materials exhibit intense emissions at room-temperature.