Synthesis Of Aggregation-induced Luminescent Molecules And Their Spectral Properties In Solution

Aggregation-induced emission phenomenon(AIE)was first proposed by Professor Tang Benzhong group,AIE molecules in the dilute solution is basically no fluorescence in the aggregation or crystal structure of the fluorescence is strong,this molecule breaks the traditional fluorescent molecules in the solid or fluorescence quenching mechanism in the aggregation state,and is widely used in the fields of organic light emitting diodes,fluorescent probes,and biological imaging.In this paper,nine kinds of molecules with aggregationinduced luminescent properties were designed and synthesized,and their spectral properties in solution were analyzed.Firstly,three amphiphilic fluorescent compounds containing styrylnaphthalene were designed and synthesized using 1-chloromethylnaphthalene and p-hydroxybenzaldehyde as starting materials.Quaternary ammonium salt was used as the hydrophilic head group,The fluorophore-styrylnaphthalene with different length alkyl chains was used as the lipophilic tail chain.The photophysical properties of these amphiphilic compounds after aqueous solution aggregation were studied.The difference of UV and fluorescence spectra of the tail-chain in aqueous solution was compared and the critical micelle concentration of the amphiphilic molecule was measured.Secondly,six coumarin benzoylhydrazones were synthesized by using 4-diethylaminosalicylaldehyde and methyl benzoate derivatives as starting materials.In order to ensure the structural correctness of each step product of nuclear magnetic resonance(NMR),carbon and mass spectroscopy.Then the six coumarin benzoyl hydrazone compound solutions were tested with different solvents.By comparing the UV spectra of these compounds,it was found that the influence of different groups and different solvents on the spectral properties of the compounds were as follows:(1)The maximum emission wavelengths of six coumarin benzoyl hydrazones are red-shifted with the increase of concentration in tetrahydrofuran solution,dimethyl sulfoxide solution,acetone solution,ethanol solution and acetonitrile solution.(2)Six coumarin benzoyl hydrazone compounds in different solvents: tetrahydrofuran solution,dimethyl sulfoxide solution,acetone solution,ethanol solution,acetonitrile solution and water should be different volume ratio of solution,the six compounds The maximum emission wavelength of redox shifted with the increasing of water volume fraction.(3)The redshift phenomenon of six coumarin benzoyl hydrazones in solutions of different concentrations and different concentrations of different solvents and water in different volume ratio,we believe that it is the result of intramolecular charge transfer(ICT),intermolecular hydrogen bonds and the formation of J-aggregates.