Jinjie Qian

Highly selective carbon dioxide adsorption in a water-stable indium–organic framework material

A metal-organic framework, with chiral 4(1) In(OH)(CO(2))(2) helix chains, exhibits a high CO(2) uptake under ambient conditions and outstanding selective separations of CO(2) from CH(4) or N(2). Its high stability toward humidity or even boiling water is confirmed by PXRD method.

An unusual bifunctional Tb-MOF for highly sensitive sensing of Ba2+ ions and with remarkable selectivities for CO2–N2 and CO2–CH4

An unusual bifunctional Tb-MOF (TbL) was synthesized by solvothermal method. Luminescent measurements show that the TbL compound exhibits high sensitivity for Ba2+ ions in DMF solution. Moreover, TbL presents significant selective capture of CO2 from the mixtures of CO2–N2 and CO2–CH4, based on the studies of gas sorption capability. To the best of our knowledge, it is the first reported Tb-MOF with such highly sensitive luminescence response for Ba2+ ions and excellent selectivities for CO2–N2 and CO2–CH4.

Thiacalix[4]arene-Supported Kite-Like Heterometallic Tetranuclear ZnIILnIII3 (Ln = Gd, Tb, Dy, Ho) Complexes

Four kite-like tetranuclear Zn(II)Ln(III)3 (Ln= Gd 1, Tb 2, Dy 3, Ho 4) clusters supported by p-tert-butylthiacalix[4]arene (H4BTC4A) have been prepared under solvothermal conditions and structurally characterized by single crystal X-ray diffraction and powder X-ray diffraction (PXRD). In the structures of these four complexes, each of them is capped by two tail-to-tail p-tert-butylthiacalix[4]arene molecules to form a bent sandwich-like unit. The photoluminescent analyses reveal that the H4BTC4A is an efficient sensitizer for Tb(3+) ions in 2. The magnetic properties of complexes 1-4 are also investigated, in which complex 3 exhibits slow magnetization relaxation typical for single molecule magnets.

Construction of Two Microporous Metal–Organic Frameworks with flu and pyr Topologies Based on Zn4(μ3-OH)2(CO2)6 and Zn6(μ6-O)(CO2)6 Secondary Building Units

By employment of a tripodal phosphoric carboxylate ligand, tris(4-carboxylphenyl)phosphine oxide (H3TPO), two novel porous metal-organic frameworks, namely, [Zn4(μ3-OH)2(TPO)2(H2O)2] (1) and [Zn6(μ6-O)(TPO)2](NO3)4·3H2O (2), have been synthesized by solvothermal methods. Complexes 1 and 2 exhibit three-dimensional microporous frameworks with flu and pyr topologies and possess rare butterfly-shaped Zn4(μ3-OH)2(CO2)6 and octahedral Zn6(μ6-O)(CO2)6 secondary building units, respectively. Large cavities and one-dimensional channels are observed in these two frameworks. Gas-sorption measurements indicate that complex 2 has a good H2 uptake capacity of 171.9 cm(3) g(-1) (1.53 wt %) at 77 K and 1.08 bar, and its ideal adsorbed solution theory calculation predicts highly selective adsorption of CO2 over N2 and CH4. Furthermore, complexes 1 and 2 exhibit excellent blue emission at room temperature.

Sorption behaviour in a unique 3,12-connected zinc–organic framework with 2.4 nm cages

A polyhedral metal–organic framework (FJI-2) has been synthesized based on rare hexanuclear zinc clusters, which comprises 2.4 nm double-walled octahedral cages topologically featuring a new 3,12-connected structure. FJI-2 has a good H2 uptake capacity of 149.7 cm3 g−1 (1.34 wt %) at 77 K and 1.0 bar, and the IAST calculation predicts highly selective adsorption of CO2 over N2 and CH4.

Stepwise construction of extra-large heterometallic calixarene-based cages.

Utilizing presynthesized large Na2Ni12Ln2 clusters (Ln = Dy and Tb) supported by calixarene as molecular building blocks (MBBs), we have obtained a series of cationic trigonal prismatic heterometallic organic nanocages (HMONCs) with tunable sizes through a stepwise method. Specially, in each structure of the HMONCs, three linear dicarboxylate linkers substitute the peripheral coordinated acetate ligands of two Na2Ni12Ln2 clusters to form an unprecedented Na4Ni24Ln4 HMONC through a M2L3 condensation. Moreover, magnetic study reveals that the Na2Ni12Dy2 core retains its slow magnetic relaxation behavior. Gas sorption behaviors of these HMONCs were also studied. To the best of our knowledge, these HMONCs built from large heterotrimetallic Na2Ni12Ln2 MBBs, which are based on smaller Ni4-calix ones, have not been reported in any other cages to date. In addition, this research also provides a new strategy for the design and construction of HMONCs with predictable structures and functional properties.

Open Pentameric Calixarene Nanocage

A novel open helmetlike coordination cage has been synthesized based on Co4-calixarene shuttlecock-like secondary building units and in situ generated phosphate anions, where the opening of the cage comprises a large 16-membered ring. The above unprecedented Co20 nanocage presents the first pentameric calixarene coordination compound. Sorption behavior and magnetic properties are also investigated.

In situ large-scale construction of sulfur-functionalized metal–organic framework and its efficient removal of Hg(II) from water

A new strategy that uses sulfur-functionalized metal organic frameworks (MOFs) for removal of Hg(II) from water has been developed. This strategy is based around a novel sulfur-functionalized MOF FJI-H12, which is composed of octahedral M6L4 cages and free NCS− groups. At the same time, large-scale synthesis of FJI-H12 microcrystals has also been carried out under very mild conditions. The resulting material can remove Hg(II) completely and selectively from water with high saturation, adsorption (439.8 mg g−1) and distribution coefficient (1.85 × 106 mL g−1) relative to other MOFs. More interestingly, a continuous and fast removal of Hg(II) from water has also been carried out using a column loaded with FJI-H12 microcrystals.

An alternative strategy to construct Fe(II)-based MOFs with multifarious structures and magnetic behaviors

An alternative strategy using cyclopentadienyliron dicarbonyl dimer as a starting material has been applied to construct six new Fe(II)-based MOFs, formulated as [Fe2(Nic)4(μ-H2O)]·CH3CN (1), [Fe(PIP)(H2O)]·H2O (2), [Fe(Hbidc)(H2O)] (3), [Fe(Hbidc)] (4), [Fe(Py-3,4-BDC)(H2O)2]·H2O (5) and [Fe(Py-3,4-BDC)(H2O)2] (6) (HNic = nicotinic acid, H2PIP = 5-(pyridin-4-yl) isophthalic acid, H3bidc = benzimidazole-5,6-dicarboxylic acid and Py-3,4-H2BDC = 3,4-pyridinedicarboxylic acid). X-ray structural analysis reveals that 1 possesses a 3D framework, while the rest of the compounds are 2D layer structures which are further connected by hydrogen bonding into 3D supramolecular architectures. Magnetic analyses have been performed with the classical spin approximation, revealing that 2, 5 and 6 exhibit ferromagnetic interactions between Fe(II) ions, while 3 and 4 show antiferromagnetic interactions between Fe(II) centres. The successful preparation of compounds 1–6 may provide an alternative and useful approach for the synthesis of Fe(II)-based MOFs in the future.

Carbon dioxide capture and conversion by an acid-base resistant metal-organic framework.

Considering the rapid increase of CO2 emission, especially from power plants, there is a constant need for materials which can effectively eliminate post-combustion CO2 (the main component: CO2/N2 = 15/85). Here, we show the design and synthesis of a Cu(II) metal-organic framework (FJI-H14) with a high density of active sites, which displays unusual acid and base stability and high volumetric uptake (171 cm3 cm−3) of CO2 under ambient conditions (298 K, 1 atm), making it a potential adsorbing agent for post-combustion CO2. Moreover, CO2 from simulated post-combustion flue gas can be smoothly converted into corresponding cyclic carbonates by the FJI-H14 catalyst. Such high CO2 adsorption capacity and moderate catalytic activity may result from the synergistic effect of multiple active sites.Increasing CO2 emissions pose serious environmental issues. Here, the authors report the synthesis of a robust metal-organic framework which displays high volumetric uptake of post-combustion CO2 under ambient conditions and can catalyze CO2 fixation into cyclic carbonates.