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With the rapid development of global industrialization, global warming and ocean acidification caused by the accumulation of greenhouse gases (such as CO 2) have attracted widespread attention. It is of great significance to use microporous metal-organic frameworks (MOFs) to adsorb carbon dioxide and further convert it into valuable chemical products. Herein, two kinds of isomorphic (MOFs): {[Ln 3 (deta) 2 (DMF) 2 (COOH)·2H 2 O]·DMF·H 2 O} n (Ln Dy(1), Tb(2), DMF = N-N-dimethyl formamide) based on 4-(3,5-dicarboxyphenoxy)phthalic acid (H 4 deta) ligands were successfully synthesized by the solvothermal synthesis method. Interestingly, MOFs 1–2 is based on a trinuclear Dy/Tb unit connected to six adjacent trinuclear Dy/Tb units via a (deta)4- ligand, extending to a 3D microporous network structure. MOFs 1–2 not only has good thermal stability, chemical stability and excellent water resistance, but also has abundant active sites of Lewis acid due to the fact that the metal center of MOFs 1–2 is lanthanides metal. The results show that MOFs 1–2 has a good catalytic activity for the chemical fixation of carbon dioxide with epoxides under moderate conditions. Moreover, they can be recycled at least 5 times without affecting their activity, showing excellent chemical stability and reusability. In addition, the reaction mechanism of CO 2 cycloaddition to PO catalyzed by MOF 1–2 was also discussed. [Display omitted] • MOFs 1–2 show 3D microporous network structure containing trinuclear lanthanides clusters. • MOFs 1–2 have good thermal stability, chemical stability and excellent water resistance. • MOFs 1–2 have abundant active sites of Lewis acid due to the lanthanide metal clusters. • MOFs 1–2 have a good catalytic activity for the chemical fixation of carbon dioxide with epoxides under mild conditions. • MOFs 1-2 show good heterogeneity, reproducibility. [ABSTRACT FROM AUTHOR]

Two europium-postdoped metal organic frameworks (MOFs) Eu3+@1 and Eu3+@2 [ 1 :{[Zn 2 (bta)(bpy)(H 2 O) 2 ]·2H 2 O} n , 2 :{[Ni(bta)(bpy)(H 2 O) 2 ][Ni(bpy)·(H 2 O) 4 ]·4H 2 O} n (H 4 bta = 1, 2, 3, 5-benzenetetracarboxylic acid, bpy = 4, 4′-dipyridine)] were prepared by hydrothermal synthesis and post-synthesis modification. MOFs 1 – 2 are all three-dimensional network structure connected by (bta)4- and bpy ligands. Eu3+@ 1 and Eu3+@ 2 in aqueous solution can achieve the quantitative detection of 2, 4, 6-trinitrobenzene (TNP), tetracycline (TC) and pesticides with high sensitivity and selectivity. In particular, when the volume of TNP increases to 50 μL, the luminescence quenching rate of Eu3+@ 2 can reach 99.7% and the LOD for TNP can reach 78 nM. Interestingly, Eu3+@1 has a good response to PTH (Pyrimethanil), while Eu3+@ 2 has a good selectivity to FLU (Fluazinam), and both can be used for rapid in-situ imaging detection of simulated pesticide residues on fresh vegetables. Under UV lamp, Eu3+@ 1 showed a significant fluorescence quenching effect on PTH in beans, while the fluorescence quenching effect of Eu3+@ 2 on FLU on cabbage was obvious. Surprisingly, two kinds of composite materials can be used as anti-counterfeiting ink functional material with strong anti-counterfeiting ability and long term stability. Two kinds of fluorescence sensors (Eu3+@ 1 and Eu3+@ 2) were synthesized by post-synthetic modification method. The sensor not only has high sensitivity, selectivity, stability and anti-interference ability to TNP, TC, PTH/FLU, but also can effectively detect pesticides on vegetables. It is particularly meaningful that they can be used as anti-counterfeiting ink. [Display omitted] • Two Eu-postdoped MOFs Eu3+@ 1 and Eu3+@ 2 were obtained by post-synthesis. • Eu3+@ 1 and Eu3+@ 2 sensors can achieve the quantitative detection of TNP, TC and pesticides with high sensitivity and selectivity. • Eu3+@ 1 has a good response to PTH, while Eu3+@ 2 has a good selectivity to FLU. • Eu3+@ 1 and Eu3+@ 2 have significant fluorescence quenching effect on PTH in bean and FLU in cabbage, respectively. • They can be used as anti-counterfeiting ink with strong anti-counterfeiting ability and long term stability. [ABSTRACT FROM AUTHOR]

A terbium metal organic framework (Tb-MOF), namely {[Tb(dppa)(H 2 O) 2 ]·dima·H 2 O·0.5O} n (1), (H 4 dppa = 5-(3′4′-dicarboxylphenoxy)isophthalic acid, dima = dimethylamine, which is formed by the decomposition of DMF in aqueous solution at high temperature.) was prepared and characterized. Tb-MOF is connected by (dppa)4- ligands via μ 4 :η1,η2,η2,η2 coordination mode to form a two-dimensional wavy network, which is extended to three-dimensional supramolecular structures based on hydrogen bonding. Tb-MOF has excellent fluorescence properties, which can be used for fluorescence recognition and quantitative determination of cation and anion, antibiotics and small organic molecules in aqueous solution with high sensitivity and good selectivity. Tb-MOF showed enhanced fluorescene for Pb2+ and B 4 O 7 2− ions, while quenching fluorescence for Cr 2 O 7 2− ion. Noticeably, this is the first time that Pb2+ and B 4 O 7 2− ions have been detected by a MOF-based fluorescence sensor using a fluorescence enhancement mechanism. More interestingly, Tb-MOF can quantitatively detect aniline (ANI) in aqueous solution by ratiometric fluorescence sensing. In addition, Tb-MOF has great selectivity and sensitivity for detecting of nitrobenzene (NB) and cefixime (CEF). In particular, when NB concentration is 50 μM, the fluorescence quenching rate of Tb-MOF reaches 99.6%. Therefore, this paper introduces a highly sensitive and multi-responsive Tb-MOF sensor, which can be used to detect Pb2+, B 4 O 7 2−, Cr 2 O 7 2−, ANI, NB and CEF with fast response speed and good selectivity. • A Tb-MOF based on H 4 dppa and dima ligands was obtained and characterized. • Tb-MOF shows a 2D wavy network structure. • Tb-MOF has excellent fluorescence properties. • Tb-MOF sensor can be used to detect Pb2+, Cr 2 O 7 2−, B 4 O 7 2−, aniline, nitrobenzene and cefixime with fast response, high sensitivity and good selectivity. • The possible fluorescence sensing mechanisms of analytes are discussed in detail. [ABSTRACT FROM AUTHOR]