Zinc(II)-MOF: A Versatile Luminescent Sensor for Selective Molecular Recognition of Flame Retardants and Antibiotics

Abstract

An exceptional Zinc(II)-organic framework with the formula [{Zn(L 4-py )(bdc)}•DMF] n (Zn-MOF) has been constructed solvothermally using a novel linker L 4-py {2,7-bis(3-(pyridin-4-ylethynyl)phenyl)benzo [lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone}, coligand H 2 bdc (1,4-benzenedicarboxylic acid), and ZnBF 4 •xH 2 O. The ligand L 4-py has been fabricated after functionalization of NDA (1,4,5,8-naphthalenetetracarboxylic dianhydride) core with 3-(pyridin-4-ylethynyl)phenyl group. The single-crystal X-ray analysis reveals that Zn-MOF exhibits a comprehensive three-dimensional (3D) framework architecture and features (4)-connected uninodal dia; 4/6/c1; sqc6 topology with point symbol {6 6 } and two-dimensional (2D) + 2D, parallel polycatenation. Notably, Zn-MOF displayed excellent fluorescence phenomenon and stability in water as well as in methanol solvents and was harnessed as a versatile sensor, demonstrating selective and sensitive molecular recognition of flame retardants and antibiotics. Notably, Zn-MOF displayed 57 and 49.5% quenching efficiency for the flame-retardant pentabromophenol (PBP) and 3,3′,5,5′-tetrabromobisphenol A (TBPA), respectively. Whereas an outstanding 90% quenching efficiency was observed for antibiotics, tetracycline (TC) and secnidazole (SD). The mechanistic investigations of this luminescence quenching suggest that this might be primarily occurring via the Fourier resonance energy transfer (FRET) and photoinduced electron transfer (PET) mechanisms, which might be assisted by the competitive absorption and host−guest interactions. The π-electron-rich framework structure of sensor Zn-MOF activates this mechanism.

A Benzothiadiazole-Based Zn(II) Metal–Organic Framework with Visual Turn-On Sensing for Anthrax Biomarker and Theoretical Calculation

“…The O(N)–Zn–O bond angles were located in the range of 87.0 (3) to 159.5 (3)°. The above data were similar to the values of the reported Zn-MOFs [ 40 ]. Furthermore, in the framework of MOF-1, the binuclear {Zn 2 (COO) 4 } as secondary building units (SBUs) with a non-bonding distance of Zn⋯Zn of 2.979 Å were observed ( Figure 1 c).…”

Two-Dimensional Cu-Based MOF for Selective Staining of the Cellular Nucleus through Fluorescence Imaging and Selective Sorption of Dye Molecules in Aqueous Medium

“…Upon excitation at 370 nm, compound 1 exhibits a broad peak centered at 525 nm. The observed emission comes out due to the intraligand transitions (π* → π and π* → n ) of the bonded organic ligands with the metal center. − The excitation spectra of the aqueous dispersion of compound 1 and pamoate ligand were recorded using an emission wavelength value of 525 nm (see Figure S9 in the SI).…”