Preparation,Structure-Activity Relationship And Biological Application Of Chemical Probe Based On Aggregation Induced Emission Property

In recent years,small molecule fluorescent probe with good selectivity,high sensitivity,is widely used in chemical?environmental?medicine and life sciences research areas.At present,there are still some limitations on the application of these chemical probes,such as lower specificity?poor membrane permeability and so on.Therefore,it is of great significance to optimize the structure of molecules to get a better selectivity,higher sensitivity and biocompatibility.(1)The crown ether group has become a rising star of donors(D)in the fluorescent chemosensor community due to their remarkable properties such as good solubility and environmental stability.Here,we select aza-crown ether as a multi-functional group and cyan group as a steric hindrance group to construct two A-?-D model structure Schiff base compounds to investigate the structure relationship.As expected,the prepared T1 and T2 both displayed Cu(?)-selective chromogenic behavior due to the crown ether group with high sensitivity and no interference.These multiple strong intermolecular interactions restrict the free rotation and rigidify the fluorophores,which largely reduced the energy loss via non-radiative relaxation channels,and subsequently resulted in a notable AIE effect.Interestingly,T2 showed an intense yellow light after grinding with a spatula for only 1 min.the mechanochromic mechanism was could be attributed to a crystalline-amorphous phase transformation.(2)We use triphenylamine fluorophore and salicylaldehyde moiety to construct a dendrimer-like probe T3 which has a sensitive and selective detection of Al3+and Cu2+ at the same time.The fluorescence responses of the probe to Al3+(Cu2+)were hardly affected by the presence of Cr3+,Fe3+,Co2+,Cd2+ and other ions,which indicated that T3 is stable in complex environments.We successful applied T3 to detect Al3+(Cu2+)in real water samples to demonstrate its real practical utility in environmental science using the calibration curves of T3 toward Al3+(Cu2+)due to its high sensitivity and selectivity.The cytotoxicity analysis,photobleach experiments indicated it was suitable for cellular imaging applications.Experiments on bioimaging applications demonstrate that T3 could be applied for specific bioluminescence imaging of intracellular Al3+ and Cu2+.Finally,the tissue experiments about Arabidopsis and zebra fish were carried out.The results exhibited that T3 not only could be used to detect Al3+ in leafs,stems and roots,respectively,but also could be unitized to visualize the Al3+ and Cu2+located both in the fish's abdomen and tail.