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In this work, a highly stable Fe-MOF, namely [Fe2(OH)2(BPTC)]·2DMF·2H2O (JOU-22, H4BPTC = biphenyl-3,3′,4,4′-tetracarboxylic acid, DMF = N,N-dimethylformamide), was solvothermally synthesized using lanthanum nitrate and HF as modulators. Single-crystal diffraction shows that JOU-22 reveals a 3D microporous framework based on Fe–O chains. Due to its high chemical stability, suitable band gap (2.1 eV), and appropriate HOMO (−0.21 V) and LUMO (1.89 V) energy, JOU-22 shows efficient visible-light induced photocatalytic activity for Cr(VI) reduction and dye degradation. JOU-22 can also be used for the degradation of organic dyes, including MB, MO, BG and RhB. Fascinatingly, in the mixed system with the co-existence of dichromate anions and MB, the degradation rate of both Cr(VI) and MB increased significantly due to the synergistic effect between the photocatalytic reduction and oxidation process. This work not only provides a new clue for the preparation of large-size Fe-MOF single crystals, but also enriches the application of Fe-MOFs in the treatment of water pollution. [ABSTRACT FROM AUTHOR]

Anionic metal–organic frameworks (MOFs) with a negatively charged framework have attracted extensive attention for their potential applications in organic dye adsorption and separation. However, the rational synthesis of anionic MOFs with tunable channel size is still difficult. In this work, two pillar-layered MOFs, namely [(CH3)2NH2]2[Zn4(BTC)2TCPB]·3DMF·H2O (JOU-44) and [(CH3)2NH2]2[Zn4(BPTC)2TCPB]·12DMF·6H2O (JOU-45), were solvothermally synthesized by using a reticular chemistry strategy (H3BTC = 1,3,5-benzenetricarboxylic acid; H3BPTC = [1,1′-biphenyl]-3,4′,5-tricarboxylic acid; H4TCPB = 1,2,4,5-tetrakis(4-carboxyphenyl)benzene). Structural analyses show that JOU-44 and JOU-45 show an isoreticular three-dimensional anionic framework based on [Zn2(COO−)5]− clusters. It should be noted that the pillar-layered framework of JOU-44 is expanded by adjusting the length of the ligands in the layer part, which is different from the pillar extension method reported in the literature. Due to its anionic and highly porous framework, JOU-44 was exploited for adsorption and chromatographic separation of organic dyes. In addition, JOU-44 was also developed as an antenna to selectively sensitize EuIII ions. This work provides a new clue for constructing pillar-layered MOFs with an extensible structure, as well as a new way to extend the applications of MOFs in separation and fluorescence. [ABSTRACT FROM AUTHOR]

A microporous indium-based metal-organic frameworks (MOFs), namely [(CH 3) 2 NH 2 ] 2 [In 2 (H 3 L) 2 (OX)]·3DMF·2H 2 O (JOU-23) (H 3 L ​= ​terphenyl-3, 4′, 5-tricarboxylic acid; OX ​= ​oxalic acid), have been solvothermal synthesized and characterized. Single-crystal X-ray diffraction show that JOU-23 displays three-dimensional anionic framework with 2-fold interpenetrated nets and rare topology. Due to its anionic and porous framework, JOU-23 can be developed for effective absorbing and separating cationic organic dyes. Further studies reveal that both the charge and size of dye molecules would affect the dyes' absorption and separation. In addition, JOU-23 dispersed in dimethyl formamide shows strong emission at about 364 ​nm. Thus, it was developed as an efficient fluorescent sensor for probing Fe3+ ions and nitroaromatic compounds. The detection limit of Fe3+ is as low as 2 ​× ​10−6 ​M (K SV ​= ​59,755 ​M−1), which is excellent in MOFs fluorescent probe. At the same time, JOU-23 shows widespread sensing performance to nitroaromatic compounds. Especially, the detection ability of JOU-23 for nitrobenzene (NB) is good. Although the NB concentration reaches only 4.175 ​× ​10−5 ​M, the quenching efficiency can achieve 86.4%. Further studies show that the quenching performance of JOU-23 is mainly attributed to the competition of excitation light absorption and the absorption of emission light by measured objects. These results indicate that JOU-23 can be applied as a multifunctional material for organic dyes adsorption/separation, Fe3+ ions detection, and nitroaromatic compounds sensing. A microporous anionic 2-fold interpenetrated In(III)-MOF has been synthesized and developed as multifunctional materials for organic dyes adsorption/separation and fluorescent sensitization of Fe3+ ions and nitroaromatic compounds. [Display omitted] • A microporous In-MOF with 2-fold interpenetrated anionic framework has been solvothermal synthesized. • JOU-23 represents a rare (3,6)-connected topology with the Schläfli symbol of (4·62) 2 (42·610·83). • JOU-23 can selective absorption and chromatographic separation of cationic dyes. • JOU-23 has been utilized as an efficient fluorescence "turn-off" sensor for probing Fe3+ ions and nitroaromatic molecules. [ABSTRACT FROM AUTHOR]