The inter-molecular hydrogen bonds modulated reversible ACQ-AIE conversion and dual-states sensing applications of shikimic acid derived hydrogen bond dimers

Abstract

Smart molecules with adjustable and reversible ACQ-AIE transformation which could be used as luminescence sensors both in solvent and solid-state are rarely reported. Planar luminophores with strong inter-molecular hydrogen bonds and a rotor might exhibit reversible ACQ-AIE conversion by modulating the inter-molecular hydrogen bonds. As a proof of concept, herein, two smart hydrogen bond dimers (Qufu-1 and Qufu-2) with reversible ACQ-AIE transformation were derived from the renewable bio-feedstock shikimic acid. Qufu-1 and Qufu-2 possessing a novel 4-oxo-3,4-dihydrobenzofuro[2,3-d]pyrimidine key structure and both exhibit crystallization induced ACQ (CIACQ) and precipitation induced AIE (PIAIE) in solid-state. Single crystal analysis indicates that the large planar configuration formed in the dimers of Qufu-1 and Qufu-2 due to the inter-molecular hydrogen bonds, which would result in the strong π-π stacking and ACQ in crystal. The AIE state could be facile realized by breaking the inter-molecular hydrogen bonds and changing the aggregation state from crystal to precipitation. Moreover, ACQ to AIE transformation could also accomplish for Qufu-1 and Qufu-2 in solution by modulating the inter-molecular hydrogen bonds with acid. In addition, three-level structures latent fingerprint identification in real environment and fluorescent sensing of hazardous biogenic amines in food samples were performed with Qufu-1.