Exfoliation of a Coordination Polymer Based on a Linear π-Conjugated Ligand into an Ultrathin Nanosheet for Glyphosate Sensing

Abstract

Owing to the large-scale consumption of pesticides and their potential threats to the environment and human health, the development of sensing materials for pesticides has attracted considerable attention in recent years. In this work, a novel Cd(II)-based coordination polymer (CP) with the formula [Cd(H 2 O) 2 (L)]•DMF (Cd-1, DMF = N,N-dimethylformamide, H 2 L = 4,4′-[(2,5-dimethoxy-1,4-phenylene)di-2,1-ethenediyl]bis-benzoic acid) was synthesized under solvothermal conditions. Structural analysis revealed that coordination between central Cd 2+ cations and the ligand L 2− formed two-dimensional (2D) networks, which were further assembled by noncovalent hydrogen bonds into a three-dimensional (3D) supramolecular framework. Through ultrasonic treatment in isopropyl alcohol, Cd-1 was exfoliated to afford an ultrathin CP-based 2D nanosheet (Cd-1-NS) with a thickness of less than 1.8 nm. Compared to the bulk materials, the prepared Cd-1-NS exhibited enhanced fluorescence emission properties and superior sensing performance toward glyphosate (Glyph) in water with high selectivity, sensitivity, anti-interference, fast response, and good recyclability via the turn-off effect. The limit of detection (LOD) of Cd-1-NS for Glyph was as low as 41 nM (7 ppb) in the low-concentration range of 0−2.4 μM. In addition, the Cd-1-NS also showed excellent practicability and reliability for the detection of Glyph in real samples, including lake water, tap water, cabbage, and watermelon skin, and could realize the rapid visualized sensing of Glyph residues on the surfaces of vegetables and fruits.

Ultrathin MOF nanosheets and their mixed-matrix membranes for ammonia and aliphatic amine sensing in water

“…They showcased the significant enhancement of sensing and fluorescence properties in MOF nanosheets compared to those in bulk materials for the detection of glyphosate (Glyph) with fast response and low detection limit in water. 28 Using a self-assembly strategy, Wong and co-workers synthesized Zn–BTC MOF nanosheets for colorimetric and fluorometric sensing of ammonia. They incorporated ZnQ to tune the properties of Zn–BTC nanosheets, which enhanced ammonia detection with a limit of detection value of 0.27 ppm in the gaseous phase and 60.8 nm in the liquid phase.…”

First Crystallographic Evidence of Polarity-Assisted Pseudohalides Controllable Heteroaldazine-Based Coordination Polymers: A New Tributary in Low Level Recognition of Explosive from Real-Day Matrices

“…Moreover, CPs demonstrate significant promise as sensors with high selectivity and sensitivity toward various lethal anions, cations, explosives, neutral compounds, etc. Preferably, in the execution of fluorescence sensing, luminescent coordination polymers (LCPs) are one of the promising candidates. , In most cases, LCPs are designed via judicious choice of fluorophoric organic building blocks, linkers, and EPR silent metal ions (e.g., the metal ions having d configuration) . The fluorophoric building blocks like fluorescein, cyanine, coumarin, rhodamine, anthracene, pyrene, naphthalene, quinoline, etc .…”