Rational Design of Three Two-Fold Interpenetrated Metal–Organic Frameworks: Luminescent Zn/Cd-Metal–Organic Frameworks for Detection of 2,4,6-Trinitrophenol and Nitrofurazone in the Aqueous Phase

Abstract

Through a dual-ligand strategy, three mixed ligands metal–organic frameworks (MOFs), namely, {[Zn2(Py2TTz)2­(BDC)2]­·2­(DMF)­·0.5­(H2O)} n (1), {[Cd2(Py2TTz)2­(BDC)2]­·2­(DMF)} n (2), and {[Co2(Py2TTz)2­(BDC)2]­·2­(DMF)­·0.5­(H2O)} n (3) (where Py2TTz = 2,5-bis­(4-pyridyl)­thiazolo­[5,4-d]­thiazole, BDC = 1,4-benzenedicarboxylate, and DMF = N,N-dimethylformamide), were synthesized under solvothermal conditions. The single-crystal X-ray diffraction analyses reveal that the three MOFs possess similar 2-fold interpenetrated three-dimensional framework structures with pcu topology. The fluorescence properties of compounds 1 and 2 were investigated systematically. The results show that compounds 1 and 2 display good fluorescent properties, which can be efficiently quenched by a trace amount of nitroaromatics 2,4,6-trinitrophenol (TNP) and antibiotics nitrofurazone (NZF) in water media. The large K sv value and small limit of detection demonstrate that compounds 1 and 2 can serve as good fluorescent sensors for TNP and NFZ detection in an aqueous system. Density functional theory calculations and spectral overlap experiments, coupled with luminescence decay experiments, confirm that the luminescence quenching mechanism involves a dynamic and static quenching mechanism and is dominated by the photoinduced electron transfer process and the Förster resonance energy transfer process simultaneously.

Dicarboxylate‐Induced Structural Diversity of Luminescent Zn(II)/Cd(II) Metal–Organic Frameworks Based on the 2,5‐Bis(4‐pyridyl)thiazolo[5,4‐d]thiazole Ligand

“…However, the luminescence intensities of compounds 5 – 7 are slightly weaker than those of the corresponding ligands 1,4‐H 2 NDC and 2,6‐H 2 NDC. It which may be attributed to the ligand to metal coordination effects, which reduces rigidity of the ligand and increases the nonradiative energy loss . The complicated luminescence properties of compounds 1 – 9 may originate from the differences in the auxiliary dicarboxylate ligands and various coordination environments around d 10 metal ions, as well as the conformations and coordination modes of the ligands.…”

“…In addition, it has been reported that some MOFs were constructed from rigid dicarboxylate and functionalized bipyridine by the mixed‐ligand strategy, which have intriguing structures and excellent properties . 2,5‐Bis(4‐pyridyl)thiazolo[5,4‐ d ]thiazole (Py 2 TTz) with rigid π‐conjugated system has good luminescence property , . Meanwhile, it integrates the features of both thiazolo[5,4‐ d ]thiazole and pyridine, possessing multiple coordination sites.…”

“…Meanwhile, it integrates the features of both thiazolo[5,4‐ d ]thiazole and pyridine, possessing multiple coordination sites. However, MOFs based on Py 2 TTz are still rarely reported , . Hence, it is interesting to introduce Py 2 TTz and different dicarboxylate ligands into MOFs by the mixed‐ligand strategy and to investigate their structural diversities and properties systematically.…”

Transition Metal–organic Coordination Polymers Containing 6‐(1H‐imidazol‐1‐yl)‐2(1H)‐Pyridinone: Synthesis, Structure and Fluorescent Sensing for Enoxacin

“…CPs have a diversity of structures since multiple coordination environments of transition metal ions. For example, Zn, Cu, Cd, Ni, and Co can adopt four‐, five‐, or six‐coordinate geometries, leading to the extended CPs from 1D to 3D dimensionality However, CPs based on the transition metal ions without unpaired electrons, especially those with d 10 configurations of Zn/Cd, can yield linker‐based high emission . So, the Zn/Cd‐luminescence coordination polymers were studied for luminescence sensing of the analytes .…”

5,5′‐(1,4‐Dioxo‐1,2,3,4‐tetrahydrophthalazine‐6,7‐diyl)bis(oxy)diisophthalate‐Based Coordination Polymers and their TNP Sensing Ability

“…The photoluminescence quenching might also be related to the stronger electron‐withdrawing ability of TNP . Here the introduced TNP changes the excited‐state electron transferring path of photoluminescence material, preventing the electronic return to the ground‐state energy levels . The organic aromatic ligand acts as the electron donor due to its electron‐rich nature.…”