Synthesis and ultraviolet/aggregation-induced emission investigation of novel tetraphenylvinyl hydrazone derivatives: efficient multimodal chemosensors for fluoride ion

Herein,three novel tetraphenylethylene hydrazone chemosensors TC12,SC16,and TC16 are prepared for the selective detection of F−.Two NH and one C=N units are incorporated into the sensors for better colorimetric responses,whereas the tetraphenyl unit is in charge of the aggregation-induced emission effect.Among them,compounds SC16 and TC16 form stable gels with some organic solvents.All the tetrahydrofuran/H2O solutions of the three compounds exhibit aggregation-induced emission effect,whereby the fluorescence emission increases by varying degrees with the volume of poor solvent water.Moreover,good aggregation-induced emission effects are observed in the self-assembly of SC16 and TC16.As a sample chemosensor,TC12 in tetrahydrofuran responds to F−selectively with high sensitivity,with the colorimetric and fluorometric detection limits of 8.25×10^(−7) mol·L^(-1) and 2.69×10^(−7) mol·L^(-1),respectively.The reversible gel-sol-gel phase transition and color changes indicate that both SC16-dimethyl sulfoxide and TC16-ethyl acetate gels specifically respond to F-with good sensitivity.The detection results are well supported by ultraviolet-visible spectroscopy,fluorescent spectroscopy,and 1H nuclear magnetic resonance.More importantly,the driving forces of gelation are visually clarified through the single crystal X-ray analysis of compound TOMe.