A novel microporous Tb-MOF fluorescent sensor for highly selective and sensitive detection of picric acid

Abstract

A new three-dimensional metal-organic framework (MOF) sensor with molecular formula (C 2 H 6 NH 2 ) 2 [Tb 2 (ptptc) 2 (DMF)(H 2 O)]$DMF$6H 2 O (complex 1) has been constructed from terphenyl-3,3 0 ,5,5 0 -tetracarboxylic acid (H 4 ptptc) and terbium nitrate under solvothermal conditions. The structure of complex 1 was characterized by single-crystal X-ray diffraction analysis (XRD), elemental analysis, IR spectroscopy and thermogravimetric (TG) analysis, and the purity was further confirmed by powder X-ray diffraction (PXRD) analysis. XRD analysis reveals that complex 1 crystallizes in a triclinic system P 1 space group and consists of a three-dimensional anionic network which has one-dimensional channels. Fluorescence titration experiments showed that complex 1 displayed real-time, highly selective and sensitive fluorescence quenching behavior towards picric acid with a nanomolar scale experimental detection limit (100 nM). Recycling titration experiments suggested that the as-synthesized probe has good reversibility and can be used for at least five cycles in fluorescence titration experiments without obvious fluorescence intensity reduction or framework structure destruction. Furthermore, the high selectivity and sensitivity as well as good recyclability of complex 1 make it a potential fluorescent sensor for picric acid.

Crystal Structure, Synthesis and Luminescence Sensing of a Zn(II) Coordination Polymer with 2,5-Dihydroxy-1,4-Terephthalic Acid and 2,2′-Bipyridine as Ligands

“…It can be seen that the complex has great potential as a luminescent probe. The Usually, we take the Stern-Volmer equation as the standard for quantitatively evaluating the luminescence quenching efficiency, I 0 /I = K sv [M] + 1, where I 0 and I are the maximum luminescent intensities before and after the addition of the complex, [M] is the molar concentration of the complex solution, and K sv is the quenching constant (M −1 ) [54][55][56]. As displayed in Figure 7b, the luminescence intensity of the suspension of the complex showed an approximately linear correlation when using Fe 3+ quenching, and perfectly followed the equation in the lower concentration range.…”

A Multifunctional Tb-MOF Detector for H2O2, Fe3+, Cr2O72–, and TPA Explosive Featuring Coexistence of Binuclear and Tetranuclear Clusters

“… 37 The Tb-MOF exhibits four well-resolved characteristic emissions, which are centered at 491, 546, 586, and 621 nm, respectively, which could be attributed to the corresponding transitions from 5 D 4 → 7 F 6 , 5 D 4 → 7 F 5 , 5 D 4 → 7 F 4 , and 5 D 4 → 7 F 3 of the Tb ion. 20 , 38 , 39 Furthermore, the fluorescence intensity of the H 5 L ligand at 325 nm excitation is negligible relative to the Tb-MOF, which indicates that the inherent fluorescence emission of the ligand has little interference with the fluorescence properties of the Tb-MOF. We used the intensity change of the strongest peak 5 D 4 → 7 F 5 (545 nm) as the detection index for analysis.…”

“…The scope of the Tb–O bond lengths is 2.291–2.892Å, and the range of the O–Tb–O bond angle is 33–149.06°, which conforms to the reported ranges of Tb–O bond length and O–Tb–O bond angle. 20 , 22 Interestingly, there are two kinds of inorganic building units in the Tb(III) 3D framework: binuclear and tetranuclear cubic metallic clusters. A binuclear metal unit consists of Tb1 and Tb4 ions (the distance of Tb···Tb is 4.0478 Å), surrounded with six DBA 5– ligands.…”

A Dy(iii)–organic framework as a fluorescent probe for highly selective detection of picric acid and treatment activity on human lung cancer cells

“…At the same time, because of the crystallinity, adjustable porosity, and special electronic structure of MOFs, they are widely used in the field of fluorescent sensors. Recently, a variety of MOFs have been combined with nitroaromatic hydrocarbons to produce luminous probes for the determination of picric acids (PAs) in water solutions [11][12][13][14]. In these MOFs, those compounds based on lanthanide metal centers have become a new research object due to their unique characteristics of long emission life, high color purity, and a large displacement of stokes.…”