Synthesis,Self-assembly And Application In Selectively Detecting Mercury Of TPE-CD Conjugate

The phenomenon of aggregation-induced emission（AIE）has important uses in solid-state luminescent materials and chemical and biosensors,so that it is attracting more and more attention.To using the host-guest interactions of AIE molecule with host compounds such as crown ether,cyclodextrin,calixarene,and cucurbituril,will make the process of self-assembly,loading,transport,and controlled release of the guest molecule be easily monitored,and can be also explored in the sensing and detection of molecular ions.This should be one of important research directions for the AIE phenomenon,but there are few research reports among this area.（1）A new type of TPE-CD conjugate was designed and synthesized.The TPE-CD conjugate and intermediate products were fully characterized by NMR spectrum,ultraviolet-visible spectroscopy,infrared spectroscopy,high-resolution mass spectrometry and other methods.Fluorescence tests show that the conjugate maintains the AIE characteristics of TPE unit.（2）TPE-CD conjugate has exhibited the phenomenon of photoelectron transfer（PET）fluorescence quenching thanks to self-inclusion.The TPE-CD conjugate can exist in a stretched form in DMSO solvent,but in the presence of a large amount of water,the TPE unit will enter the cyclodextrin cavity to form a folded self-inclusion compound.Interestingly,since the TPE unit is close to the triazole ring directly connected to the cyclodextrin rim in the self-inclusion compound,PET process from the TPE unit to the triazole ring occurs,which quenches the fluorescence.Therefore,after adding a large amount of water into the DMSO solution of the conjugate,the fluorescence is not enhanced but quenched although there is more aggregation.This is the first finding that this type of self-inclusion compound not only has the AIE phenomenon,but also displays the PET effect.（3）It can be used for highly selective detection of metal mercury ions.In addition,through ¹H NMR spectra,it is found that Hg²⁺can selectively coordinate with triazole,inhibiting the PET process from TPE unit to triazole ring,therefore the fluorescence is increased by addition of Hg²⁺.In summary,this article has thoroughly studied the synthesis and characterization of TPE-CD conjugate,the host-guest self-inclusion process,the mechanism of PET fluorescence quenching,and the highly selective sensing of mercury ions.It is of great significance for synthesizing better chemical sensors and biosensors based on the phenomena of AIE and PET.