Highly Selective Bifunctional Luminescent Sensor toward Nitrobenzene and Cu²⁺ Ion Based on Microporous Metal–Organic Frameworks: Synthesis, Structures, and Properties

Abstract

Two metal-organic frameworks (MOFs), namely, [Ni(DTP)(HO)] (I) and [Cd(DTP)(bibp)] (II) (HDPT = 4'-(4-(3,5-dicarboxylphenoxy) phenyl)-4,2':6',4″-terpyridine; bibp = 1,3-di(1H-imidazol-1-yl)propane), that present structural diversity were solvothermally prepared. Single-crystal X-ray diffraction analysis indicates that they consist of {NiNO} building units (for I) and {CdON} and {CdON} building units (for II), which are further linked by multicarboxylate HDPT to construct microporous three-dimensional frameworks. The remarkable character of these frameworks is that coordination polymer II demonstrates highly selective and sensitive bifunctional luminescent sensor toward nitrobenzene and Cu ion. The fluorescence quenching mechanism of II caused by nitrobenzene is ascribed to electron transfer from electron-rich (II) to electron-deficient nitrobenzene. The result was also evidenced by the density functional theory. Furthermore, anti-ferromagnetic as well as electrochemical characters of Ni-MOF (I) were also investigated in this paper.

Highly Selective and Stable Zn (II)‐Based Metal–Organic Frameworks for the Detections of Tetracycline Antibiotic and Acetone in Aqueous System

“…[ 22 ] The frontier orbital energy of 10 antibiotics and 1 were calculated by DFT (B3LYP) using 6–31 + G(d) basis set. [ 37 ] It can be seen from Figure 9, the maximum quenching efficiency of TC was consistent with the lowest LUMO energy. The LUMO energy of TC was lower than that of 1 , so electrons were transferred from the conduction band of 1 to the LUMO of TC upon excitation, thereby causing fluorescence quenching.…”

An Azacrown[N,S,O]–Styryl Modified Boron–Phenylpyrrin: Coordination‐Mode‐Transition‐Induced Colorimetric and OFF–ON–OFF Fluorescence Chemosensor for Quantifying Cu2+

“…Dichloromethane was freshly distilled from CaH 2 under nitrogen. The precursor boron–phenylpyrrin compound (BPP‐A) and p ‐azacrown[N,S,O]–benzaldehyde were prepared according to the published procedures , …”

“…Fluorescence‐sensing methods have attracted increasing attention in recent years due to their high sensitivity, rapid responsiveness, and low detection limits, resulting in the synthesis of a large number of fluorescence sensors with different detection functions . Notably, despite the development of a wide range of Cu 2+ detecting fluorescence sensors, based on excellent chromophores, such as BODIPY, porphyrin, and rhodamine, their single OFF–ON/ON–OFF fluorescence‐signal‐dependent nature limits their accurate quantification of Cu 2+ , which prefers an OFF–ON–OFF fluorescence response . Actually, investigations into OFF–ON–OFF fluorescence sensors for accurately quantifying Cu 2+ still remain rare, probably due to the complicated molecular‐design strategies needed to meet the structural and electronic requirements, such as different Cu 2+ affinities, higher turn‐on intensities, and lower background fluorescence …”

A new iron-based metal–organic framework with enhancing catalysis activity for benzene hydroxylation

“…Attributing to the exibility in choosing the building blocks, various MOFs with adjustable pore sizes and shapes as well as tunable internal chemical environments are designed and synthesized. 12 Up to now, a vast number of MOFs are synthesized and used in a wide range of applications including but not limited to gas and vapour storage/separation, [13][14][15] proton conduction, [16][17][18] catalysis, 19,20 sensing, [21][22][23] and drug delivery. 24,25 Recently, various Fe-based MOFs were synthesized and exhibited interesting properties.…”