Chiral Tin‐Oxo Cluster Matrices with Fluorophore Embedment for Multichromatic Circularly Polarized Luminescence

Enantiomeric tin-oxo clusters form helical supramolecular matrices through directional intermolecular interactions, enabling efficient transfer of optical handedness to encapsulated non-chiral fluorophores via spatial confinement. These assemblies exhibit tunable circularly polarized luminescence (CPL) emissions.

Abstract

Tin-oxo clusters, characterized by their well-defined chemical compositions and architectures, are multi-metal aggregates composed of Sn-oxide cores and surface ligands. Chirality, a fundamental characteristic governing biological recognition and signal transduction, remains underexplored in stannate clusters compared to extensively studied precious metal clusters. Herein, three enantiomeric pairs of chiral tin-oxo clusters were constructed using axially chiral 1,1′-bi-2-naphthol (BINOL) ligands. Structural analyses revealed supramolecular helical assemblies mediated by directional C─H···π interactions, while circular dichroism (CD) spectroscopy confirmed their intrinsic chirality. Through in situ doping engineering, non-chiral fluorophores with distinct emission profiles were incorporated during chiral cluster crystallization, yielding composite materials exhibiting circularly polarized luminescence (CPL). The optimized system achieved a maximum dissymmetry factor (g _lum) of 1.5 × 10⁻². Mechanistic studies established that the spiral packing of the tin-oxo clusters facilitates stereochemical information transfer to the dyes via the spatial confinement effect. This supramolecular chirality induction paradigm offers new insights into the rational design of multifunctional optical materials.

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