Design And Performance Of New Fluorescent Chemosensors Containing Benzimidazole

Human life is closely related to the water environment.At present,the pollution of metal ions in the waters is severe and affects human health.As an important trace element in the body,Cu²⁺needs to be maintained at a low level in human cells.It can be seen that the detection and monitoring of the Cu²⁺content in the environment and organisms is very necessary and significant.Fluorescent chemosensors can specifically identify metal ions in environments and organisms.They have the advantages of high selectivity and sensitivity,low cost,easy operation,real-time detection and rapid response.In this paper,benzimidazole was used as a fluorophore,diaminomaleimide,2-picolinic acid and acrylonitrile were used as acceptors.Four new fluorescent chemosensors were designed and synthesized,and their ability to detect metal ions was explored.The main work of this paper:1.Fluorescence chemosensor L that enhances the fluorescence and changes the UV visible absorption ratio after identifying Cu²⁺has been designed and synthesized.Fluorescence and UV visible absorption spectra showed that the sensor L could exhibit specific fluorescence enhancement and absorption spectrum ratio change in aqueous solutions in a wider pH range.Both methods were selective and had low detection limits.It can be seen that the complex ratio of L to Cu²⁺was 1:2 through the testing of fluorescence spectrum,mass spectrometry and DFT calculation.Confocal laser scanning microscopy images of HepG2 cells showed that sensor L had cell permeability and intracellular Cu²⁺detection ability on biologic cells.2.Chemosensor P that generates fluorescence quenching after identifying Cu²⁺has been designed and synthesized.Fluorescence spectroscopy showed that the sensor P can specifically identify Cu²⁺with good selectivity and low detection limit in acetonitrile solution through fluorescence quenching.The working curve and B-H curve showed that the complex ratio of sensor P to Cu²⁺was 1:1.3.Two small-molecule benzimidazole derivatives,2-?1H-benzo[d]imidazol-2-yl?Phenyl pyridinate?Compound A?and 3-?2-?pyridine-?,2-yl?-1H-benzo[d]imidazol-1-yl)propionitrile?Compound B?were designed and synthesized.Fluorescence spectra were tested in different solvents?acetonitrile;acetonitrile:water 1:1;ethanol;ethanol:water 1:1?and two molecules were found to have a certain response to metal ions,but the selectivity was not high.