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

• Published in: Inorganic chemistry Vol. 58; no. 12; pp. 8198 - 8207
• Main Authors: Xu, Wenfeng, Chen, Hanhua, Xia, Zhengqiang, Ren, Chongting, Han, Jing, Sun, Wujuan, Wei, Qing, Xie, Gang, Chen, Sanping
• Format: Journal Article
• Language: English
• Published: American Chemical Society 17.06.2019
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.9b01008

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.