Study On Optical Properties And Mechanism Of Naphthalimide Derivatives With Mechano-responsive Luminescence

Recently,the emergence of mechanoresponsive luminescence materials has attracted wide attention because of its characteristics of wavelength change in solid state after being stimulated by mechanical stimulation,and has great application potential in many aspects such as optics,mechanical sensors,anti-counterfeiting technology,etc.Generally speaking,the molecular structure with mechanoresponsive luminescence behavior generally has a moderate distortion so that the molecular accumulation mode changes under the influence of external mechanical stimulation,increasing the non-radiation jump pathway,eventually causing fluorescence to change.In addition,some studies have shown that the existence of hydrogen bonds and weak intermolecular interaction forces such as CH···? in some molecules can inhibit the rotation and vibration of the molecules,thereby inhibiting non-radiative transitions,resulting in a change in the fluorescence intensity of the fluorescent material in the solid state.Because of its good plane and special photophysical chemistry,it is widely used as the main body for the synthesis of some fluorescent dyes,and it is reported that the derivatives of pyrethroids are mostly probes used to detect biological systems,or one of the ingredients of synthetic drugs,and the study of frictional luminescence behavior has not yet been reported.In this paper,a series of fluorescent dye molecules with good planarity have been synthesized by modifying 4-bromo-1,8-naphthalenedicarboxylic acid anhydride,and the photophysical and chemical properties of the three compounds in solution and solid state are further studied through the corresponding characterization.1.Introduce the n-butyl group at the 1-position of 4-bromo-1,8-Naphthalene dimethylanhydride,use the naphthalene ring with greater conjugation effect as the ? group,and introduce hydrazine at the 4-position as the ? bridge,and then separately introduce benzaldehyde,salicylaldehyde and p-hydroxybenzaldehyde to study their triboluminescence behavior and related applications.BN-1,BN-2 and BN-3 are three naphthalimide derivatives with good planarity.All three compounds have similar chemical properties,but due to the excited-state intramolecular proton transfer(ESIPT)in the BN-1 molecule,its optical properties are significantly higher than the other two compounds.In different solvent background,they all show obvious solventization effect,and with the change of solvent polarity,it is easy to produce obvious changes.Compared with BN-2 and BN-3,BN-1 has a higher fluorescence quantum yield in the solution,and the photophysical chemistry of the aggregate state is studied,it is found that with the increase of water content,all three compounds show the trend of decreased fluorescence intensity and eventual annihilation,and the properties of the three compounds are further studied through theoretical simulation.2.The photophysical chemistry of three compounds in solid state is studied.First of all,the three compounds are fully ground,through fluorescence intensity research and comparison found that BN-2 frictional luminescence behavior is significantly stronger than the other two compounds,before grinding,BN-2 emits a very bright yellow fluorescence,fluorescence intensity is significantly higher than the other two compounds,and after grinding,BN-1 fluorescence intensity is reduced almost annihilation,while BN-2 and BN-3 before and after grinding there is no very obvious frictional luminescence behavior,This suggests that differences in hydroxyl positions may cause differences in the performance of the three compounds in macrophysical properties,and by studying their properties under different characters before and after grinding,it is well demonstrated that all three compounds exhibit different physical states before and after grinding.Finally,the crystal structure properties of BN-1 are obtained by analyzing single crystals,we further understand the reason why the intramolecular hydrogen bond may cause the triboluminescence behavior of the compound.3.Through the three compounds before and after grinding the state of scanning electroscopic characteristics,and further understand the structure of molecular microscopy.At the same time,there are three compounds in different states.The properties of the devices were studied and the potential uses of the compounds were explored.