Dual-functional fluorescent chemosensor with large stokes shift based on 2D poly(3-amino-carbazole) for efficient p-nitroaniline and Fe3+ detection

Abstract

In this work, two 2D poly (3-aminocarbazole) derivatives containing N-type acceptor moietiesbenzothiadiazole and benzofurazan were synthesized and reported, which are named PCBTC and PCBFC respectively. UV spectrum shows that the absorption spectrum of the new polymers with N-type structures both have a red shift compared with poly (3-aminocarbazole). The fluorescence spectrum shows that PCBTC has a strong fluorescence emission (Em = 544 nm) at 375 nm excitation with a large stokes shift of 169 nm, which is conducive to its use as a highly sensitive fluorescence probe with strong anti-interference ability. As expected, our results show that p-nitroaniline and ferric ions perform visual fluorescence quenching effect on PCBTC respectively compared with other ions and aromatic compounds. The results show the limits of detection of PCBTC to p-nitroaniline and Fe3+can reach 21.5 nM and 71.4 nM respectively. What is more interesting and noteworthy is that the isomers o-nitroaniline and m-nitroaniline of p-nitroaniline almost will not quench the fluorescence of PCBTC. These results consistently indicate that PCBTC can be used as a dual-functional probe to detect p-nitroaniline and Fe3+.