A Robust Tb^III-MOF for Ultrasensitive Detection of Trinitrophenol: Matched Channel Dimensions and Strong Host–Guest Interactions

Abstract

Host–Guest interaction is crucial to the sensitivity of heterogeneous sensors. Here, a series of isomorphic three-dimensional lanthanide metal–organic frameworks (Ln-MOFs), [Ln­(TCBA)­(H2O)2]2·DMF [H 3 TCBA = tris­(3′-carboxybiphenyl)­amine; Ln = Tb (1), Eu (2), and Gd (3); DMF = dimethylformamide] was synthesized and characterized, in which the propeller-like TCBA 3– ligands adopt special torsional link between Tb­(III) ions to form one-dimensional triangular channels. Optical experiments show that 1 exhibits bright green luminescence with an overall quantum yield of 26%, a 5D4 lifetime of 478 μs, and can act as an excellent heterogeneous fluorescent sensor to detect 2,4,6-trinitrophenol (TNP) explosive with an extremely low detection limit of 1.64 ppb. Because the confined channels within 1 exhibit matched dimensions toward TNP and feature multiple guest-response sites including rich π-conjugated groups, electron-donating N centers, and open metal nodes, strong host–guest interactions between 1 and TNP are captured and accurately determined by online microcalorimetry, which provides a distinctive thermodynamic perspective to understand the heterogeneous sensing behaviors. Additionally, the finely modulated heterometallic isomorphism [Tb0.816Eu0.184(TCBA)­(H2O)2]2·DMF emits bright white light when excited at 380 nm and could potentially be used as single-phase white light-emitting diode phosphors materials.

Recent advances in process engineering and upcoming applications of metal–organic frameworks

“…3H 2 O. DMF] n Cr 2 O 7 2− 0.058 µM 5 [419] [[Cu I 2 (ttpa) 2 ][Cu II (bptc)]. 3H 2 O. DMF] n CrO 4 2− 0.07 µM 5 [419] Cd-MOF S 2 O 8 2− – – [412] [Eu 2 L 3 (DMF)]·2 DMF PO 4 3− 6.62 µM – [420] c. Sensors for explosive compounds AuNCs/ZIF-8 TNT 5 nM – [413] [Tb(TCBA)(H 2 O) 2 ] 2 ·DMF TNP 1.64 ppb 5 [414] UIO-66-Py TNP 0.45 µM – [421] Eu-MOF TNP 0.03 mM – [422] Eu-MOF NB 0.04 mM – [422] Eu-MOF PNT 0.09 mM – [422] Eu-MOF PNP 0.08 mM – [422] HNU-34 TNP 36.15 nM 5 [415] HNU-34 2,4 DNP 42.55 nM 5 [415] ...…”

“…A lanthanide-based MOF ([Tb(TCBA)(H 2 O) 2 ] 2 ·DMF) was employed for the selective sensing of TNP, a simulant of TNT [414] . The luminescent probe exhibited excellent sensing ability, with an extremely low detection limit of 1.64 ppb.…”

Conductive MOFs with Photophysical Properties: Applications and Thin-Film Fabrication

“…DMF/EtOH solutions of Zn(NO 3 ) 2 •6H 2 O, TCPP, DMBPY and 1 M HNO 3 /EtOH were heated at 80 °C for 2 h, followed by the immersion of annealed ZnO-FTO slides into the above precursor solutions at upright positions at 80 °C for 30 min, which led to spontaneous formation of uniform crystalline films. Solar cells based on the as-synthesized PPF-11/ ZnO-FTO photoanode exhibited superior photovoltaic response with power conversion efficiency up to 0.86%, which was significantly linked to the covalent attachment to ZnO surface and [100] orientation of PPF-11 films.…”

Coordination Polymers Based on Highly Emissive Ligands: Synthesis and Functional Properties

“…Pronounced luminescence quenching effect allowed to achieve low acetone detection limit of about 0. [218]. Upon excitation at 380 nm Gd-MOF showed emission at 435 nm, which is blue-shifted relative to the free ligand (462 nm).…”