首页|A luminescent covalent organic framework with recognition traps for nitro-pesticides detection,pH sensing and metal ions identification
A luminescent covalent organic framework with recognition traps for nitro-pesticides detection,pH sensing and metal ions identification
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NSTL
Special recognition sites in luminescent covalent organic frameworks(LCOFs)are extremely important to improve the selectivity of detection.Herein,we report on a novel LCOF named TFBD-Py-COF with three-in-one recognition traps composed of hydrogen bonding,reversible protonation of N and O-H···N=C chelating unit.TFBD-Py-COF is synthesized via 3,3',5,5'-tetraformyl-4,4'biphenyldiol(TFBD)and 4,4',4",4'''-(pyrene-1,3,6,8-tetrayl)tetra aniline(PyTTA),which has a two-dimensional dual rhombic pore structure based on AA stacking with the pore diameters of 0.88 and 1.38 nm.The hydroxyl group of TFBD-Py-COF can form hydrogen bonds with imines and induce the trans conformation of the mesoimine,as evidenced by the single crystal structure of the model compound.TFBD-Py-COF exhibits good chemical and thermal stability with a high BET surface area of 750 m~2 g~(-1).TFBD-Py-COF shows visible fluorescent color from blue to green when dispersed in different organic solvents.TFBD-Py-COF has the fluorescence chemo-sensing ability for nitro-pesticides based on electron transfer-induced fluorescence quenching mechanism,allowing a high sensitivity and low detection limit of 4.0 × 10~(-2)ppm for p-nitroaniline.In addition,TFBD-Py-COF shows reversible acidochromic behaviors and concomitant distinct fluorescent color change due to the protonation of the imine N.Furthermore,the fluorescence of TFBD-Py-COF is selectively quenched by Fe~(3+)with a Ksv of 1.1 × 10~4 and a detection limit of 0.2 μM,owing to the coordination of Fe~(3+)with the O-H···N=C chelating unit.This study demonstrates great potential of LCOFs for multifunctional detection.
The Key Laboratory of Synthetic and Biological Colloids,Ministry of Education,School of Chemical and Material Engineering,Jiangnan University,Wuxi,214122,PR China
NSTL
