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

Abstract

The direct ion exchange of chloro(2,6-bis(N-methylbenzimidazol-2-yl)pyridine)platinum(II) ([Pt(Me(2)bzimpy)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(Me(2)bzimpy)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(Me(2)bzimpy)Cl]+-exchanged ZrP colloidal methanol suspension gives rise to an emission at 612 nm that originates from a lowest (3)MMLCT[dsigma*(Pt) --> pi*(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(Me(2)bzimpy)Cl]+ and [Pt(tpy)Cl]+ ions can serve as luminescent pillars inside the ZrP framework.

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

“…38 Recently, we reported that the direct ion-exchange of two monomeric platinum complexes, [Pt(Me 2 bzimpy)Cl] + (Me 2 bzimpy = 2,6-bis(N-methylbenzimidazol-2-yl)pyridine) and [Pt(tpy)Cl] + (tpy = 2,2′:6′,2″-terpyridine), into layered inorganic material zirconium phosphate (θ-ZrP) 39−42 produces novel luminescent materials. 43 Those results were consistent with an expansion of the interlayer spacing to about 18 Å to accommodate aggregates of closely interacting platinum complexes. Suspensions and powders of these intercalated materials exhibit distinct absorption and emission spectroscopic signatures characteristic of low-lying metal−metal-to-ligand charge transfer (MMLCT) states resulting from short Pt···Pt spacings.…”

Metal Complexes Supported on Solid Matrices for Visible‐Light‐Driven Molecular Transformations

“…a-ZrP allows for intercalation of large guest molecules within the restricted interlayer space via an ion-exchange or phase-boundary mechanism, taking the advantage of the strong electrostatic interaction between the exchangeable proton and the guest molecules with positive charge. [77] Although property changes induced by the macroheterogeneous surroundings of a-ZrP have been reported on intercalation of various luminescent complexes, such as [Ru(bpy) 3 ] 2 + , [78] [Pt(tpy)Cl] + , [79] and [Re(phen)(CO) 3 Cl], [80] their prominent photocatalytic activities have scarcely been investigated to date. [81] Much effort has been dedicated to the efficient photocatalytic conversion of CO 2 into energetically beneficial molecules, such as carbon monoxide, methane, formic acid, or methanol.…”

Vapochromic and mechanochromic films from square-planar platinum complexes in polymethacrylates

“…The overall behaviour is consistent with the vapochromic response and electronic structures of Pt(Mebip)Cl + salts and related compounds. 47,55,56,76 The resulting emission bandshape and energy are characteristic of a lowest 3 MMLCT transition, 55,56,75 in which the excited molecule is less distorted than in the case of a more localized unimolecular MLCT state. The emission profiles are very similar for the four different blends, indicating that the emissive vapor-exposed platinum crystallites have essentially the same structures for this selection of polymers.…”

“…[34][35][36] These Pt-Pt interactions can be strongly influenced by the coordinating ligand and its substituents as well as the counterion used, which can allow for tuning of the spectroscopic properties. [37][38][39][40] Studies involving the use of platinum complexes with either terpyridine [41][42][43][44][45] or 2,6-bis(benzimidazol-2 0 -yl)pyridine 46,47 have gained interest largely as a consequence of their tendency to exhibit strong photoluminescence originating from their lowest excited states having significant ligand charge-transfer and/or metal-toligand charge-transfer character. The absorption and emission properties of these complexes typically are quite sensitive to external stimuli in solution and as solids.…”