Efficient Construction of Elastic and Ion Response Red Fluorophores with Crystallization-Induced Enhanced Emission and Large Stokes Shifts

Flexible red-emissive fluorophores have important potential applications in fluorescent sensors, flexible organic electronic materials, and other luminescent materials. Herein, dimethyl 1,2,3,4,6,7,8,9-octahydropyrido[2,3-g]quinoline-5,10-dicarboxylate, which is a novel flexible red fluorophore with a large Stokes shift up to 231 nm, was designed and successfully synthesized by a one-pot three-step tandem reaction. It demonstrates red emission in solution (about 635 nm) and enhanced red emission in the crystallized state. Additionally, the butterfly-like tricyclic architecture displays elastic property, acid/ base vapor stimulus response, and selective fluorescence detection of Cu2+. It provides a feasible and efficient strategy for multifunctional fluorophores compared with the typical extended pi-conjugated systems.