Synthesis Of Dinaphthimide Derivatives And Spectral Study Of Solvent Response

Fluorescent dyes are widely used in the fields of materials,biology and chemistry.The optical properties of fluorescent dyes are influenced by the external conditions,such as temperature,concentration,pressure and solvent.Among them,solvent controlled fluorescent dyes have been widely studied.The mechanisms were mainly to control the intra-molecular electron transfer process and intermolecular electron transfer process.In recent years,a series of fluorescent dyes with the twisted intra-molecular electron transfer?TICT?process and aggregation-induced fluorescence enhancement?AIE?process have been developed.While,fluorescent dyes based on solvent-controlled C-C single bond rotation process were limited.In this paper,a series of C-C single bond bridged double naphthalimide derivatives were designed and synthesized.Furthermore,their optical properties were studied by UV-Vis,fluorescence and ¹H NMR analyses.This work developed a new method for C-C single bond rotation based fluorescent dyes.1.A series of C-C single bond bridged double naphthalimide derivatives were synthesized by Suzuki coupling reaction for three steps.The double naphthalimide derivatives included N,N-dimethyl ethylenediamine modified naphthalimide derivative 2NI-NN,triglycol amine modified naphthalimide derivative 2NI-3Gan,dodecylamine modified naphthalimide derivative 2NI-12An,2,6-diisopropyl aniline modified naphthalimide derivative 2NI-26,?S?-1-cyclohexyl ethylamine modified naphthalimide derivative 2NI-2S and?R?-1-cyclohexyl ethylamine modified naphthalimide derivative 2NI-2R.These compounds were characterized by ¹H NMR,¹³C NMR and MS analyses.2.The optical properties of the C-C bridged double naphthalimide derivatives were studied by solvent-dependent UV-Vis,fluorescence and ¹H NMR analyses.Compounds 2NI-NN?2NI-3Gan and 2NI-12An showed the optical properties of double naphthalimide backbones by intramolecular interactions in the polar solvents.And in the weak polar solvents,these compounds exhibited the optical properties of naphthalimide backbone.These results indicated that compounds 2NI-NN?2NI-3Gan and 2NI-12An showed solvent-controlled optical properties.in addition,compounds 2NI-26,2NI-2S and 2NI-2R showed no solvent-controlled optical properties,which was mainly due to enhanced steric hindrance effect in the imino position.3.The complex interactions of 2NI-NN-I with C4SONa,ATP and CB[8]were also studied.These results indicated that enhanced steric hindrance effect in the imide position seriously decreased the electronic interactions between the double naphthalimide backbones.