Superhydrophobic MOF/polymer composite with hierarchical porosity for boosting catalytic performance in an humid environment.

The poor hydrostability of most reported metal-organic frameworks (MOFs) has become a daunting challenge in their practical applications. Recently, MOFs combined with multifunctional polymers can act as a functional platform and exhibit unique catalytic performance; they can not only inherit the outstanding properties of the two components but also offer unique synergistic effects. Herein, an original porous polymer-confined strategy has been developed to prepare a superhydrophobic MOF composite to significantly enhance its moisture or water resistance. The selective nucleation and growth of MOF nanocrystals confined in the pore of PDVB-vim are closely related to the structure-directing and coordination-modulating properties of PDVB-vim. The resultant MOF/PDVB-vim composite not only produces superior superhydrophobicity without significantly disturbing the original features but also exhibits a novel catalytic activity in the Friedel-Crafts alkylation reaction of indoles with trans-ß-nitrostyrene because of the accessible sites and synergistic effects.

Solvent-Induced In(III)-MOFs with Controllable Interpenetration Degree Performing High-Efficiency Separation of CO2/N2 and CO2/CH4.

Herein, three In(III)-based metal-organic frameworks (In-MOFs) with different degrees of interpenetration (DOI), namely In-MOF-1, In-MOF-2, and In-MOF-3, constructed by In3+ and Y-shaped ligands 4,4',4″-s-triazine-2,4,6-triyltribenzoate (H3TATB), are successfully synthesized through the ionothermal/solvothermal method. Subsequently, three novel In-MOFs, including noninterpenetration polycatenation, 2-fold interpenetrated, and 4-fold interpenetrated structure, are employed as the platform for systematically investigating the separation efficiency of CO2/N2, CO2/CH4, and CO2/CH4/N2 mixture gas system. Among them, In-MOF-2 shows the highest CO2 uptake capacities at 298 K and simultaneously possesses the low adsorption enthalpy of CO2 (26.4 kJ/mol at low coverage), a feature desirable for low-energy-cost adsorbent regeneration. The CO2/N2 (v: v = 15/85) selectivity of In-MOF-2 reaches 37.6 (at 298 K and 1 bar), also revealing outstanding selective separation ability from flue gases and purifying natural gas, affording a unique robust separation material as it has moderate DOI and pore size. In-MOF-2 shows exceptional stability and feasibility to achieve reproducibility. Aperture adjustment makes In-MOF-2 a versatile platform for selectively capturing CO2 from flue gases or purifying natural gas.

Defect engineering improves CO2/N2 and CH4/N2 separation performance of MOF-801.

A defect engineering modification method is reported to improve the CO2/N2 and CH4/N2 separation performance of MOF-801, owing to skeleton shrinkage caused by defect modification, Zr-FA0.5 shows excellent gas separation performance compared with the prototype MOF.

Superhydrophobic MOFs with enhanced catalytic activity for chemical fixation of CO2.

A general approach to prepare superhydrophobic MOFs (denoted as MOFs-CF3) through a post-decorating strategy for highly efficient chemical fixation of CO2 was demonstrated. The enhanced catalytic activity of MOFs-CF3 is attributed to a synergistic effect between the Lewis acid sites of MOFs and modification of the electron-withdrawing trifluoromethyl group, which resulted in a high CO2 enrichment capacity. The possible mechanism of cycloaddition catalyzed by the MOFs-CF3 catalyst was also proposed.

Pore Space Partitioning MIL-88(Co): Developing Robust Adsorbents for CO2/CH4 Separation Featured with High CO2 Adsorption and Rapid Desorption.

Metal-organic frameworks (MOFs) have attracted significant attention as sorbents for gas separation and purification. Ideally, an industrially potential adsorbent should combine exceptional gas uptake, excellent stability, and a lower regeneration energy; however, it remains a great challenge. Here, by utilizing the pore space partition (PSP) strategy, we develop three isostructural MOF materials (Co-BDC-TPB, Co-DCBDC-TPB, and Co-DOBDC-TPB) based on pristine MIL-88(Co). The three pore-space-partitioned crystalline microporous MOFs have triangular bipyramid cages and segmented one-dimensional channels, and among them, Co-DOBDC-TPB exhibits the highest CO2 uptake capacity (4.35 mmol g-1) and good CO2/N2 (29.7) and CO2/CH4 (6.2) selectivity. The selectivity-capacity synergy endows it with excellent CO2/N2 and CO2/CH4 separation performance. Moreover, Co-DOBDC-TPB can complete desorption within 10 min. The satisfactory CO2 adsorption ability can be attributed to both microporous aperture arising from PSP and modification of the pore surface by the polar hydroxy group, which enhances the interaction between Co-DOBDC-TPB and CO2 molecules significantly. The exceptional regeneration property may be due to its lower CO2 isosteric heat of adsorption (23.6 kJ/mol). The developed pore-space-partitioned MIL-88(Co) material Co-DOBDC-TPB may have potential application to flue gas and natural gas purification.

Green Synthesis of MOF-801(Zr/Ce/Hf) for CO2/N2 and CO2/CH4 Separation.

The purification of natural gas and the removal of carbon dioxide from flue gases are crucial to economize precious resources and effectively relieve a series of environmental problems caused by global warming. Metal-organic framework (MOF) materials have demonstrated remarkable performance and benefits in the area of gas separation; however, obtaining materials with high gas capacity and selectivity simultaneously remains difficult. In addition, harsh synthesis conditions and solvent toxicity have been restricted in large-scale production and industrial application. Therefore, MOF-801(Zr/Ce/Hf) was created based on the green synthesis of the MOF-801 construction unit by altering the kinds of metal salts, and the impact of three metal nodes on the performance of gas adsorption and separation was demonstrated by contrasting the three MOFs. The results showed that MOF-801(Ce) has the best CO2 adsorption capacity (3.3 mmol/g at 298 K), which also was demonstrated with in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) results, CO2/CH4 (ideal adsorbed solution theory (IAST) = 13.28 at 298 K, 1 bar, CO2/CH4 = 1:1, v/v), and the separation performance of CO2/N2 (IAST = 57.46 at 298 K, 1 bar, CO2/N2 = 1:1, v/v) among the group. Green synthesis of MOF-801(Zr/Ce/Hf) is an ideal candidate for flue gas separation and methane purification because of its high regeneration capacity and strong cyclic stability.

Bis-(di-methylamine-κN)bis[4-(1,2,4-triazol-1-yl)benzoato-κO]copper(II).

In the title compound, [Cu(C9H6N3O2)2(C2H7N)2], the Cu2+ cation is situated on an inversion center and is coordinated by the N atoms of two di-methyl-amine ligands and the carboxyl-ate O atoms of two 4-(1,2,4-triazol-1-yl)benzoate anions, leading to a slightly distorted square-planar N2O2 coordination environment. In the crystal, inter-molecular N-H⋯N hydrogen bonds between the amine function and the central N atom of the triazole ring lead to the formation of ribbons parallel to [11]. Weak inter-molecular C-H⋯O hydrogen-bonding inter-actions are also observed that consolidate the crystal packing.

Polymelamine Formaldehyde-Coated MIL-101 as an Efficient Dual-Functional Core-Shell Composite to Catalyze the Deacetalization-Knoevenagel Tandem Reaction.

Porous organic polymer (POP) coated on a metal-organic framework (MOF) has the functions and advantages of MOF and POP at the same time and has excellent catalytic ability. In this study, an efficient dual-functional core-shell composite MOF@POP with Lewis acid and Brønsted base sites was synthesized using the impregnation method in which MIL-101(Cr) was the core component and polymelamine formaldehyde (PMF) was the shell component. Most importantly, the obtained MIL-101(Cr)@PMF showed perfect catalytic activity in the deacetalization-Knoevenagel tandem reaction. In addition, it could still maintain ultrahigh physical and chemical stability.

A [(M2)6L8] metal-organic polyhedron with high CO2 uptake and efficient chemical conversion of CO2 under ambient conditions.

A new metal-organic polyhedron with a high surface area of 407 m2 g-1, possessing high CO2 uptake, is reported, which is synthesized using 4-connected Cu2(CO2)4 paddle-wheel moieties and 3-connected semi-rigid tripodal carboxylates. This material possesses a high density of Cu(II) Lewis acidic sites and demonstrates excellent performance as a heterogeneous catalyst for the chemical fixation of CO2 into cyclic carbonates under ambient conditions.

Trifunctional Metal-Organic Framework Catalyst for CO2 Conversion into Cyclic Carbonates.

Herein, we reported a facile strategy for the preparation of trifunctional ionic metal-organic frameworks (MOFs) incorporating imidazolium cation functionalities. This strategy exploits the Debus-Radziszewski reaction to create the cationic imidazole ring by postsynthetic modification, meanwhile introducing exchangeable counteranions. On the basis of this strategy, MIL-101-IMOH-Br- has been synthesized, which combines Lewis acidic sites, Brønsted acidic sites, and nucleophilic centers to achieve catalysis for the carbon dioxide-epoxide cycloaddition into cyclocarbonate without any cocatalyst and solvent.

The applications and prospects of hydrophobic metal-organic frameworks in catalysis.

In recent years, large numbers of hydrophobic/superhydrophobic metal-organic frameworks (MOFs) have been developed. These hydrophobic MOFs not only retain rich structural variety, highly crystalline frameworks, and uniform micropores, but they also have lower affinity towards water and boosted hydrolytic stability. Until now, there were two main strategies to prepare hydrophobic MOFs, including a one-step method and post-synthesis modification (PSM). PSM was an often-used strategy for preparing hydrophobic MOFs. Hydrophobic MOFs showed unique advantages when used as catalysts for various categories of reactions. Herein, recent research advances relating to hydrophobic MOFs in the catalytic field are presented. The catalytic activities of hydrophobic MOFs and corresponding hydrophilic ones are also compared, and the superiority of hydrophobic MOFs or MOF materials as catalysts in 10 reactions is discussed. Finally, the advantages of hydrophobic MOFs as catalysts or auxiliary materials are summarized and promising future developments of hydrophobic MOFs are highlighted.

Disparity in clinical outcomes between pure and combined pulmonary large-cell neuroendocrine carcinoma: A multi-center retrospective study.

OBJECTIVES: The 2015 World Health Organization classification defines pulmonary large-cell neuroendocrine carcinoma (LCNEC) as a high-grade neuroendocrine carcinoma. However, the clinical characteristics and prognostic factors of pure LCNEC and combined LCNEC remain unclear. Hence, we performed a multi-center retrospective study to compare the clinical outcomes of pure versus combined LCNEC. MATERIALS AND METHODS: Data from 381 patients with pulmonary LCNEC admitted to 17 Chinese institutes between 2009 and 2016 were collected retrospectively. Clinical characteristics and prognosis were analyzed among patients receiving adjuvant (adjuvant group; n = 56) and first-line (first-line group; n = 146) chemotherapy, as well as among patients receiving small cell lung cancer (SCLC) and non-SCLC (NSCLC) chemotherapy regimens. The Kaplan-Meier method and multivariable Cox regression were used to identify clinicopathological variables that might influence patient outcomes. RESULTS: Expression levels of neuroendocrine markers (synaptophysin, chromogranin-A, CD56) were associated with patients' prognosis in the total study cohort. In the adjuvant group, median disease-free survival was non-significantly longer for SCLC-based regimens than for NSCLC-based regimens (P = 0.112). In the first-line group, median progression-free survival was significantly longer for SCLC-based regimens than for NSCLC-based regimens (11.5 vs. 7.2 months, P = 0.003). Among patients with combined LCNEC, adenocarcinoma was the most common combined component, accounting for 70.0 % of cases. Additionally, median overall survival was non-significantly shorter for combined LCNEC than for pure LCNEC (P = 0.083). CONCLUSION: The SCLC regimen is a more effective choice, as either first-line or adjuvant chemotherapy, when compared to the NSCLC regimen for LCNEC treatment. Further studies are needed to clarify the survival differences between patients with pure-, and combined LCNEC.

An exceptionally stable core-shell MOF/COF bifunctional catalyst for a highly efficient cascade deacetalization-Knoevenagel condensation reaction.

A novel strategy has been developed to construct a highly stable core-shell MOF@COF (PCN-222-Co@TpPa-1) bifunctional catalyst through strong π-π stacking interaction. This hybrid material with spatially isolated antagonistic acid-base sites can effectively catalyze the deacetalization-Knoevenagel condensation cascade reaction.

Highly Efficient Cooperative Catalysis of Single-Site Lewis Acid and Brønsted Acid in a Metal-Organic Framework for the Biginelli Reaction.

A unique 3D framework containing three different types of nanoscale polyhedron cages was constructed by incorporating dinuclear [M2(µ2-OH)(COO)4] (M = Co, Ni) secondary building units and pyridyl-carboxylic-acid-supported tetracarboxylates. The assembled complexes possess isolated bifunctional single-site Lewis acid and Brønsted acid and can be used as highly efficient heterogeneous catalysts for the solvent-free Biginelli reaction with a high turnover frequency value of 338.4 h-1. Interestingly, a variety of 3,4-dihydropyrimidin-2(1 H)-ones have been obtained in high yields and short times.

A highly stable nanofibrous Eu-MOF membrane as a convenient fluorescent test paper for rapid and cyclic detection of nitrobenzene.

A stable fluorescent nanofibrous membrane was fabricated by in situ growing Eu-MOF crystals on electrospun polyacrylonitrile nanofibers modified with γ-aminobutyric acid. This nanofibrous membrane can be used as a convenient fluorescent test paper for rapid and cyclic detection of nitrobenzene.

Superhydrophobic/Superoleophilic MOF Composites for Oil-Water Separation.

A universal strategy is developed to construct metal-organic framework (MOF)-based superhydrophobic/superoleophilic materials by the reaction of activated MOFs and octadecylamine. In particular, S-MIL-101(Cr) composite can efficiently separate chloroform, toluene, petroleum ether, and n-hexane from water with excellent oil-water separation performance, with potential application in the environmental field.

Hollow core-shell ZnO@ZIF-8 on carbon cloth for flexible supercapacitors with ultrahigh areal capacitance.

Rational design and synthesis of hollow core-shell hetero-structures with high complexity still remains challenging for high-performance supercapacitors. Here, a simple and effective strategy that involves a 'root-etch-wrap' process was developed to synthesize hollow core-shell hetero-structured electrodes. Specifically, ZnO hollow spheres take root on carbon cloth via an in situ growth routine, then are etched to aid the generation of a ZIF-8 shell. As-synthesized hollow core-shell ZnO@ZIF-8 is wrapped by PANI nanocoating, resulting in a flexible conductive porous electrode (denoted as PANI/ZnO@ZIF-8-CC). The optimized electrode exhibits an ultrahigh areal capacitance (4839-3987 mF cm-2 at 5-30 mA cm-2), which is at least 3 times higher than that of PANI-CC and ZnO@ZIF-8-CC owing to the synergistic effect. In addition, a symmetric flexible supercapacitor fabricated by PANI/ZnO@ZIF-8-CC exhibits a high energy density of 0.137-0.0891 mW h cm-3 (at a power density of 1.421-23.629 W cm-3) and a good long-term cycling ability (87% for 10 000 cycles at 5 mA cm-2). All of these results make unique core-shell structured PANI/ZnO@ZIF-8-CC a promising electrode material for advanced energy storage and conversion applications.

Robust Bifunctional Core-Shell MOF@POP Catalyst for One-Pot Tandem Reaction.

A new bifunctional acid-base catalyst, core-shell UiO-66@SNW-1, with robust chemical and thermal stability, recyclability, and durable catalytic activity is synthesized by a convenient, universal strategy. Interestingly, this hybrid material can effectively catalyze deacetalization-Knoevenagel condensation reaction in the presence of excellent compartmentalization to spatially isolate opposing acid-base sites.

Palladium Nanoparticles Encapsulated in the MIL-101-Catalyzed One-Pot Reaction of Alcohol Oxidation and Aldimine Condensation.

A bifunctional catalyst, Pd nanoparticles (NPs) encapsulated in MIL-101, has been synthesized by capillary impregnation. The as-prepared Pd@MIL-101 was characterized by powder X-ray diffraction, N2 physisorption, X-ray photoelectron spectroscopy, transmission electron microscopy, and high-angle annular dark field scanning transmission electron microscopy, indicating that Pd NPs were highly dispersed in the pores of MIL-101 without deposition of the nanoparticles on the external surface or aggregation. The bifunctional catalyst of Pd@MIL-101 exhibited highly catalytic activity for alcohol oxidation and aldimine condensation one-pot reactions, where Pd NPs affords good oxidation activity and MIL-101 offers Lewis acidity. In particular, Pd@MIL-101 yielded an effective catalytic performance with toluene as the solvent, K2CO3 as the co-catalyst, and 353 K as the optimum reaction temperature for the one-pot reaction. After five cycles of reuse, Pd@MIL-101 still shows high catalytic performance. Above all, it is found that the enhanced catalytic performance was achieved via the synergistic cooperation of MIL-101 and Pd NPs.

Robust Bifunctional Lanthanide Cluster Based Metal-Organic Frameworks (MOFs) for Tandem Deacetalization-Knoevenagel Reaction.

A series of 12-connected lanthanide cluster based metal-organic frameworks (MOFs) have been constructed by [Ln6(µ3-OH)8(COO-)12] secondary building units (SBUs) and 2-aminobenzenedicarboxylate (BDC-NH2) ligands. These obtained materials exhibit high chemical stability and generic thermal stability, especially in acidic and basic conditions. They also present commendable CO2 adsorption capacity, and Yb-BDC-NH2 was further confirmed by a breakthrough experiment under both dry and wet conditions. Moreover, these materials possess both Lewis acid and Brønsted base sites that can catalyze one-pot tandem deacetalization-Knoevenagel condensation reactions.