Fabrication of Fluorescent Supramolecular Organic Frameworks through Host-Guest Interaction and Its Application for Ratiometric Detection of I

Abstract

The construction of fluorescent supramolecular organic frameworks (SOF) through host-guest interaction not only enables the construction of functional aggregates with diverse structures, but also effectively regulates the luminescent properties of the molecules. Herein, we synthesized a chalcone based fluorescent amphiphilic molecule (molecule 1). The molecule 1 could aggregates into nanospheres with emission color changed from yellow to green. After co-assembly with γ-cyclodextrin (γ-CD) through host-guest interaction, three-dimensional cube-like SOF structures were obtained. The emission color could be regulated from green to blue through adjusting the concentration of complex. More importantly, the supramolecular complex suppressed the aggregation-caused quenching (ACQ) nature of molecule 1 that bright luminescence can be sustained in both solid state and solution. Based on the stable emission property of 1/γ-CD, we developed a ratiometric fluorescence platform for detection of I- using the 1/γ-CD as a reference signal combined with orange luminescent gold nanoclusters (AuNCs). The redox reaction between I- and AuNCs induces fluorescence quenching of AuNCs and no change to that of 1/γ-CD complex, resulting in a low detection limit of 0.042 μM.