Shuo Yao

Two stable 3D porous metal–organic frameworks with high performance for gas adsorption and separation

Two porous MOFs, [NO3][In3OL3]·4DMF·3H2O (JLU-Liu18) and [CdL]·0.5DMF (JLU-Liu19), H2L = pyridine-3,5-bis(phenyl-4-carboxylic acid), have been solvothermally synthesized and structurally characterized. Both of the two compounds possess a saturated coordination metal centre without open metal sites (OMSs) leading to remarkable thermal and water vapour stability. JLU-Liu18 displays a rare occurrence of 9-connected, trinuclear [In3O(CO2)6N3] secondary building units (SBUs) in a porous crystal, with high adsorption for small gases, especially CO2 (129 and 400 cm3 g−1 at 273 and 195 K, respectively, under 1 bar). It also performs with commendable selectivity for O2 over N2, and CO2, C2H6, C3H8 over CH4. JLU-Liu19 possesses outstanding performance for sieving small gases owing to its ultramicropores of 3.5 A. Both of the two MOFs are promising materials for gas adsorption and purification.

Two heterovalent copper–organic frameworks with multiple secondary building units: high performance for gas adsorption and separation and I2 sorption and release

With the help of the multiple secondary building unit (SBU) strategy, two novel heterovalent Cu–MOFs, [(Cu4I4)Cu4L4(DABCO)2]·16DMF (JLU-Liu31) and [(Cu4I4)Cu3L3(DABCO)(DMF)2]·18DMF (JLU-Liu32) [H2L = pyridine-3,5-bis(phenyl-4-carboxylic acid), DABCO = 1,4-diazabicyclo[2.2.2]-octane], have been successfully solvothermally synthesized and structurally characterized. Both of the two compounds feature multiple SBUs and exhibit novel topologies. JLU-Liu31 possesses the largest sustainable pore volume among the MOFs based on Cu4I4 clusters. Moreover, the adsorption behaviours of the desolvated JLU-Liu31 material for some small gases (H2, O2, CO2, CH4, C2H6 and C3H8) have been analysed in low pressure regions; meanwhile, it exhibits commendable selectivity for O2 over N2, and C3H8 over CH4. The remarkable results illustrate that JLU-Liu31 is a good candidate for application in the separation of light hydrocarbons. Additionally, JLU-Liu32 exhibits impressive performance for I2 sorption and release in solvents.

An ultrastable Zr-MOF for fast capture and highly luminescence detection of Cr2O72− simultaneously in an aqueous phase

Herein, using the modulator synthesis approach, a zirconium-based metal–organic framework (Zr-MOF), [Zr6O4(OH)4L4(H2O)2(HCOO)4]·9DMF·12H2O (JLU-MOF50, L = H2MDCPB = 5′-methyl-[1,1′,3′,1′′-terphenyl]-4,4′′-dicarboxylic acid, DMF = N,N-dimethylformamide), with pcu topology was successfully synthesized and structurally characterized. JLU-MOF50 exhibits excellent chemical stability in both acidic and alkaline aqueous solutions. Due to the missing linker sites, high porosity (BET surface area of 1101 m2 g−1), and excellent luminescence property, JLU-MOF50 possesses dual functionalities, which exhibits not only a commendable trapping capacity (92 mg g−1) and an adsorption rate (32.5 mg g−1 min−1), but also high detection sensitivity and selectivity for Cr2O72− in an aqueous phase. It is worth mentioning that the KSV value of JLU-MOF50 towards Cr2O72− can reach up to 4.99 × 104 M−1, which is one of the highest values reported to date for MOF materials. Based on the aforementioned properties, JLU-MOF50 is a good candidate for fast capture and highly luminescence detection of Cr2O72− simultaneously in an aqueous phase.

A Flexible Doubly Interpenetrated Metal–Organic Framework with Breathing Behavior and Tunable Gate Opening Effect by Introducing Co2+ into Zn4O Clusters

A Zn4O clusters based flexible doubly interpenetrated metal-organic framework [(Zn4O)2(DCPB)6DMF]·2DMF·8H2O (JLU-Liu33, H2DCPB = 1,3-di(4-carboxyphenyl)benzene, DMF = N,N-dimethylformamide) with pcu topology has been solvothermally synthesized. Because of its flexible structure, JLU-Liu33 exhibits a breathing behavior upon N2 and CO2 adsorption at low temperature, and C2H6 and C3H8 adsorption at 273 and 298 K. Furthermore, by adopting the direct synthesis method, two isomorphic compounds-JLU-Liu33L and JLU-Liu33H-have been obtained by partial substituting Zn with different amounts of Co into the JLU-Liu33 framework. The gas adsorption study of Co-doped materials reveals that the gate opening effect of JLU-Liu33 can be modulated by introducing different contents of Co2+ into Zn4O clusters. Meanwhile, with the increasing amount of Co2+, the adsorption amount and isosteric enthalpy values for CO2 have been improved. It is worth mentioning that JLU-Liu33H exhibits commendable selectivity for CO2 over CH4 which may be a good candidate for industrial gas purification and air separation applications.

A novel trinuclear Cd(II) cluster-based metal–organic framework: synthesis, structure and luminescence properties

A novel three-dimensional metal–organic framework (MOF), [H3O][Cd3Cl(PZC)3(H2O)3] (1), has been synthesized based on a trinuclear Cd(II) cluster and H2PZC ligand (H2PZC = 1H-pyrazole-4-carboxylic acid). Compound 1 crystallizes in a trigonal crystal system with the space group R3m. Trinuclear Cd(II)-clusters as secondary building units (SBU) are further connected by the H2PZC ligand to form a two-fold interpenetrated 3D framework. Compound 1 exhibits excellent water-stability and good luminescence properties for various organic solvents and different metal ions. The systematic investigation for luminescence indicates that compound 1 possesses unique performance for the detection of acetone, Fe2+ and Na+ based on a fluorescence quenching and enhancing mechanism, thus it can be regarded as a potential luminescence probe for the detection of acetone, Fe2+ and Na+.

Assembly of an indium–porphyrin framework JLU-Liu7 : a mesoporous metal–organic framework with high gas adsorption and separation of light hydrocarbons

By reacting with indium nitrate and tetrakis(4-carboxyphenyl)-porphyrin (H4TCPP), a mesoporous indium–porphyrin framework, named JLU-Liu7, which features a rare (4,4)-connected frl net based on 1D inorganic indium rod SBUs, has been constructed. It exhibits high performance for gas adsorption and light hydrocarbon separation.

Two Analogous Polyhedron-Based MOFs with High Density of Lewis Basic Sites and Open Metal Sites: Significant CO2 Capture and Gas Selectivity Performance

By means of modulating the axial ligand and adopting supermolecular building blocks (SBBs) strategy, two polyhedron-based metal-organic frameworks (PMOFs) have been successfully synthesized [Cu6(C17O9N2H8)3(C6H12N2)(H2O)2(DMF)2]·3DMF·8H2O (JLU-Liu46) and [Cu6(C17O9N2H8)3(C4H4N2)(H2O)2(DMF)2]·3DMF·8H2O (JLU-Liu47), which possess a high density of Lewis basic sites (LBSs) and open metal sites (OMSs). Since the size of axial ligand in JLU-Liu47 is smaller than that in JLU-Liu46, JLU-Liu47 shows larger pore volume and higher BET surface area. Then, the adsorption ability of JLU-Liu47 for some small gases is better than JLU-Liu46. It is worthwhile to mention that both of the two compounds exhibit outstanding adsorption capability for CO2 ascribed to the introducing of urea groups. In addition, the theoretical ideal adsorbed solution theory (IAST) calculation and transient breakthrough simulation indicate that JLU-Liu46 and JLU-Liu47 should be potential materials for gas storage and separation, particularly for CO2/N2, CO2/CH4, and C3H8/CH4 separation.