Synthesis Of Strong Fluorescent Materials And Applications In The Detection Of Nitro-explosives

Nitroaromatic compounds,especially nitro-explosives,are widely present in social life,posing significant risks to the living environment and human security.It is very significance to develop fast,low-cost,portable explosive detection methods for environmental governance and homeland security.Fluorescent sensors have become an important sensing and detection method due to their advantages such as obvious signal changes,easy detection,and nondestructive testing of samples.In order to develop high sensitivity and selectivity fluorescence sensors,the key to solving this problem is to synthesize fluorescent compounds with high fluorescence intensity.In this thesis,two series of novel high intensity fluorescent materials have been synthesized by using anthracene and tetraphenylethylene（TPE）as the core luminescent structural units,respectively,for the detection of nitro explosives and enhanced fingerprint recognition.The main contents are as follows:1.Based on the anthracene structural unit,one-dimensional DPA1 and two-dimensional DPA2 were designed and synthesized.The pure products of DPA1 and DPA2 were obtained by vacuum sublimation method.Their UV visible absorption spectra and fluorescence emission spectra in different solvents were tested.Both compounds showed high absolute fluorescence quantum yields.The fluorescence quenching method was used to test the detection effect of two compounds on small molecules nitro explosives such as trinitrotoluene（TNT）,trinitrophenols（PA）and 3-Nitrophenol（3-NP）.The maximum quenching constant reached 6.3×10⁴M^-1,showing that these two compounds are excellent sensing materials for explosive detection,and the sensing mechanism has been studied by using DFT theoretical calculations and spectroscopy methods.Furthermore,the fingerprint recognition effect is greatly enhanced based on its high intensity fluorescence.2.Three fluorescent compounds with TPE as the terminal group were designed and synthesized,and three pure compounds were obtained by vacuum sublimation.Their photophysical properties were characterized by UV visible absorption spectroscopy,fluorescence emission spectroscopy.All three compounds exhibit significant aggregation induced luminescence effects.Then,the strong fluorescence properties of the three compounds were used for nitro explosive detection and fingerprint identification.In explosives detection,classic nitro explosives small molecules TNT,PA,and 3-NP were selected as the research objects,and analyzed the detection effects of the three explosives by using Stern-volmer curves.It was found that the three compounds were more sensitive to PA,with Ksv reaching respectively4.8×10⁴M^-1,5.8×10⁴M^-1and 8.2×10⁴M^-1.Based on the fact that FQ-TPE and Wu-TPE have absolute quantum yields of up to 70%,further research on fingerprint recognition enhancement has been carried out by using these two compounds.