AIEE active dual-state emissive tripodal pyridopyrazine derivatives as multi-stimuli responsive smart organic materials

Abstract

This work presents the synthesis of five novel pyridopyrazine derivatives (PPDs) PP1–PP5. These PPDs have high quantum yields (Φ) up to 0.87 in solid and solution states. This dual-state emissive behavior was supported by AIEE properties. Single crystal X-ray diffraction (SCXRD) studies confirmed the absence of π–π stacking interactions in the unit cell. The SCXRD analysis of PP4 also revealed a twisted conformation and herringbone packing arrangement. All pyridopyrazine derivatives detected TFA reversibly in solution and the powdered state. Probe PP2 was also incorporated in the guar-gum borax hydrogel matrix and could detect TFA in the gel phase with a color change from blue to yellow. These PPDs were also exploited for their metal sensing abilities and could selectively sense Hg²⁺ ions with detection limits in ppm. Theoretical studies were also raised to support experimental findings. The changes in emissive properties with increasing temperature from 30 °C to 80 °C were also studied for these PPDs.