Synthesis,Photochromism and Fluorescence of Naphthopyran-tetraphenylethylene Hybrid
A novel class of naphthopyran-tetraphenylethylene hybrids NP1—NP5 were designed and synthesized,and their photochromic and fluorescent properties were investigated in detail.Compared to 2,2-diphenyl-2H-benzo[h]chromene(NP0),the thermal fading rate of NP5 has significantly improved with the fastest half-time(τ1/2)of 0.75 min.Such kind of compounds also exhibited fast photo-responsive speed and excellent fatigue resistance.In addition,the tetrahydrofuran solution of NP2 is fluorescent,which can be quenched by an irradiation with 360 nm UV light.However,no aggregation-induced emission was observed for these compounds.