Photoluminescence enhancement by controllable aggregation and polymerization of octanuclear gold clusters

Abstract

Aggregation-induced luminescence behaviors of polynuclear metal clusters are intriguing but still mysterious to date. Herein, we synthesize a series of Au₈ clusters with different peripheral ligands to investigate their different supramolecular assembly and distinguishable aggregation-induced luminescent behaviors in solution upon the variation of concentration and solvent polarity. Complex 1a is surrounded by two tetraphenyl ethylene (TPE) moieties, whose dense stacking engenders strong aggregation in solution. Furthermore, the incorporation of the TPE-decorated gold clusters into a polymer backbone promotes molecular restriction within a constrained polymer micelle and thus facilitates efficient emission enhancement of gold clusters. In contrast, the other two gold clusters with small ethynylbenzene and chloride as peripheral ligands exhibit low emission efficiency. The contrastive study showcases how the peripheral ligand arrangements influence assemblies of metal clusters and potentiates such effects in the rational design of cluster-based luminescent materials.