Synthesis And Properties Of Fluorescent Chemosensor Based On Carbazole-Schiff

Trace elements play an important role in human normal life activities.They are harmful to humans and organisms at high concentration or low concentration.So how to quickly test the concentration of metal ions is particularly important.Fluorescent chemical sensors based on carbazole schiff base can not only detect metal ions efficiently,accurately and low-cost,but also transfer electron quickly.More and more scientists are turning to fluorescent chemical sensors base on carbazole schiff base recently.This paper includes the following two parts:First,a new chemosensor named 2-amino-3((Z)-((9-hexyl-9H-carbazol-3-yl)methylene)amino)maleonitrile(sensor 1)was synthesized.Carbazole was used as the fluorescent group and 2,3-diaminomaleonitrile acted as the receptor.The molecular structure of sensor 1 was characterized with IR,1H NMR,13 C NMR,HRMS and other methods.Sensor 1 could selectively identify copper ions efficiently with fluorescence response,but did not produce obvious fluorescence response upon the addition of K+,Ag+,Mn2+,Co2+,Ni2+,Zn2+,Cd2+,Pb2+,Mg2+,Ca2+,Sr2+,Ba2+,Hg2+,Fe2+,Fe3+,Al3+ and Cr3+.The binding constant between sensor 1 and Cu2+ was evaluated to be 1.35×106 M-1.The detection limit was calculated to be 2.74×10-8 M.The binding stoichiometry of sensor 1 and Cu2+ was 1:1.Second,another new chemsensor called 2.3-bis((Z)-((9-hexyl-9H-carbazol-3-yl)methylene)amino)maleonitrile(sensor 2)was synthesized on the base of 2-amino-3((Z)-((9-hexyl-9H-carbazol-3-yl)methylene)amino)maleonitrile(sensor 1).The molecular structure was characterized with IR,1H NMR,13 C NMR,HRMS and other methods.Sensor 2 could selectively identify Fe3+ efficiently according to fluorescence response,but did not form complex with other metals.The binding constant between sensor 2 and Fe3+ was evaluated to be 7.98×106 M-1.The detection limit was calculated to be 3.75×10-8 M.The binding stoichiometry of sensor 1 and Cu2+ was 1:1.