Room-Temperature Emission from Platinum(II) Complexes Intercalated into Zirconium Phosphate-Layered Materials

The direct ion exchange of chloro(2,6-bis(N-methylbenzimidazol-2-yl)pyridine)platinum(II) ([Pt(Me₂bzimpy)Cl]⁺) and chloro(2,2‘:6‘,2‘ ‘-terpyridine)platinum(II) ([Pt(tpy)Cl]⁺) complexes within a zirconium phosphate (ZrP) framework has been accomplished. The physical and spectroscopic properties of [Pt(Me₂bzimpy)Cl]⁺ and [Pt(tpy)Cl]⁺ intercalated in ZrP were investigated by X-ray powder diffraction and X-ray photoelectron, infrared, absorption, and luminescence spectroscopies. In contrast to unintercalated complexes in fluid solution, which do not emit at room temperature, both intercalated materials in the solid state and in colloidal suspensions exhibit intense emissions at room temperature. A [Pt(Me₂bzimpy)Cl]⁺-exchanged ZrP colloidal methanol suspension gives rise to an emission at 612 nm that originates from a lowest ³MMLCT[dσ*(Pt) → π*(tpy)] state (MMLCT = metal−metal-to-ligand charge transfer) characteristic of strong Pt···Pt interactions. A [Pt(tpy)Cl]⁺-exchanged ZrP colloidal aqueous suspension exhibits a strong emission band at 600 nm. The accumulated data demonstrate that at high concentrations, [Pt(Me₂bzimpy)Cl]⁺ and [Pt(tpy)Cl]⁺ ions can serve as luminescent pillars inside the ZrP framework.