Tuning Multiple Counter-Anions in Porous Coordination Polymers with lcy Topology for Acetylene/Ethylene Separation.

The efficient separation of acetylene (C2H2) and ethylene (C2H4) is an important and complex process in the industry. Herein, we report a new family of lcy-topologic coordination frameworks (termed NTU-90 to NTU-92) with Cu3MF6 (M = Si, Ti, and Zr) nodes. These charged frameworks are compensated by different counterbalanced ions (MF62-, BF4-, and Cl-), yielding changes in the size of the window apertures. Among these frameworks, NTU-92-a (activated NTU-92) shows good adsorption selectivity of C2H2/C2H4 and also significant ability in recovering both highly pure C2H4 (99.95%) and C2H2 (99.98%). Our work not only presents a potential alternative for energy-saving purification of C2 hydrocarbons but also provides a new approach for tuning the function of charged porous materials.

Exploring the impact of TGF-ß family gene mutations and expression on skin wound healing and tissue repair.

Transforming Growth Factor-Beta (TGF-ß) signalling pathway is of paramount importance in the processes of wound healing, epidermal integrity maintenance and development of skin cancer. The objective of this research endeavour was to clarify the impact of gene mutations and variations in expression within TGF-ß family on mechanisms of tissue repair, as well as to identify potential targets for therapeutic purposes in non-melanoma skin cancer (NMSC). The methods utilized in this study involved obtaining RNA-seq data from 224 NMSC patients and paired normal skin tissues from the PRJNA320473 and PRJEB27606 databases. The purpose of the differential gene expression analysis was to identify genes whose expression had changed significantly. In order to evaluate the effects and interrelationships of identified gene variants, structural analysis with AlphaFold and PDB data and network analysis with the STRING database were both utilized. Critical gene expression was externally validated through the utilization of the GEPIA database. Tumour tissues exhibited a notable upregulation of genes associated with the TGF-ß pathway, specifically MMP1, MMP3, MMP9, EGF, COL3A1 and COL1A2, in comparison with normal tissues. As indicated by the central node status of these genes in the network analysis, they play a crucial role in the progression of NMSCs. The results of the structural analysis suggested that mutations might cause functional disruptions. External validation of the upregulation confirmed the expression trends and emphasized the biomarker potential of the upregulated genes. In conclusion, this research offered thorough examination of molecular modifications that occur in TGF-ß family genes, which are linked to cutaneous wound healing and NMSC. The modified expression of the identified hub genes may represent innovative targets for therapeutic intervention.

Immobilization of Amino-site into a Pore-Partitioned Metal-Organic Framework for Highly Efficient Separation of Propyne/Propylene.

Adsorptive separation of propyne/propylene (C3H4/C3H6) is a crucial yet complex process, however, it remains a great difficulty in developing porous materials that can meet the requirements for practical applications, particularly with an exceptional ability to bind and store trace amounts of C3H4. Functionalization of pore-partitioned metal-organic frameworks (ppMOFs) is methodically suited for this challenge owing to the possibility of dramatically increasing binding sites on highly porous and confined domains. We here immobilized Lewis-basic (-NH2) and Lewis-acidic (-NO2) sites on this platform. Along with an integrated nature of high uptake of C3H4 at 1 kPa, high uptake difference of C3H4-C3H6, moderated binding strength, promoted kinetic selectivity, trapping effect and high stability, the NH2-decorated ppMOF (NTU-100-NH2) can efficiently produce polymer-grade C3H6 (99.95 %, 8.3 mmol ⋅ g-1) at room temperature, which is six times more than the NO2-decorated crystal (NTU-100-NO2). The in situ infrared spectroscopy, crystallographic analysis, and sequential blowing tests showed that the densely packed amino group in this highly porous system has a unique ability to recognize and stabilize C3H4 molecules. Moving forward, the strategy of organic functionalization can be extended to other porous systems, making it a powerful tool to customize advanced materials for challenging tasks.

Confining Water Nanotubes in a Cu10O13-Based Metal-Organic Framework for Propylene/Propane Separation with Record-High Selectivity.

Energy-efficient separation of propylene (C3H6)/propane (C3H8) is in high demand for the chemical industry. However, this process is challenging due to the imperceptible difference in molecular sizes of these gases. Here, we report a continuous water nanotube dedicatedly confined in a Cu10O13-based metal-organic framework (MOF) that can exclusively adsorb C3H6 over C3H8 with a record-high selectivity of 1570 (at 1 bar and 298 K) among all the porous materials. Such a high selectivity originates from a new mechanism of initial expansion and subsequent contraction of confined water nanotubes (∼4.5 Å) caused by C3H6 adsorption rather than C3H8. Such unique response was further confirmed by breakthrough measurements, in which one adsorption/desorption cycle yields each component of the binary mixture high purity (C3H6: 98.8%; C3H8: >99.5%) and good C3H6 productivity (1.6 mL mL-1). Additionally, benefiting from the high robustness of the framework, the water nanotubes can be facilely recovered by soaking the MOF in water, ensuring long-term use. The molecular insight here demonstrates that the confining strategy opens a new route for expanding the function of MOFs, particularly for the sole recognition from challenging mixtures.

Delicate Softness in a Temperature-Responsive Porous Crystal for Accelerated Sieving of Propylene/Propane.

Soft nanoporous crystals with structural dynamics are among the most exciting recently discovered materials. However, designing or controlling a porous system with delicate softness that can recognize similar gas pairs, particularly for the promoted ability at increased temperature, remains a challenge. Here, we report a soft crystal (NTU-68) with a one-dimensional (1D) channel that expands and contracts delicately around 4 Å at elevated temperature. The completely different adsorption processes of propane (C3H8: kinetic dominance) and propylene (C3H6: thermodynamic preference) allow the crystal to show a sieving separation of this mixtures (9.9 min·g-1) at 273 K, and the performance increases more than 2-fold (20.4 min·g-1) at 298 K. This phenomenon is contrary to the general observation for adsorption separation: the higher the temperature, the lower the efficiency. Gas-loaded in situ powder X-ray analysis and modeling calculations reveal that slight pore expansion caused by the increased temperature provides plausible nanochannel for adsorption of the relatively smaller C3H6 while maintaining constriction on the larger C3H8. In addition, the separation process remains unaffected by the general impurities, demonstrating its true potential as an alternative sorbent for practical applications. Moving forward, the delicate crystal dynamics and promoted capability for molecular recognition provide a new route for the design of next-generation sieve materials.

Ligand-Functional Groups Induced Tuning MOFs' 2D into 1D Pore Channels for Pipeline Natural Gas Purification.

The solvothermal reactions of CoCl2 ⋅ 6H2 O, 3,5-pyridinedicarboxylic acid (H2 L) and isonicotinic acid (HL1 )/3-amino isonicotinic acid (HL2 )/3-chloro isonicotinic acid (HL3 ) successfully led to three tfz-d topological pillar-layer [Co4 (µ-F)2 (COO)6 (NC5 H4 )4 ] cluster-based MOFs, namely, [Co4 (µ-F)2 (L)2 (L1 )2 ⋅ 2DMA] ⋅ DMA ⋅ 2H2 O (SNNU-Bai76, SNNU-Bai=Shaanxi Normal University Bai's group), [Co4 (µ-F)2 (L)2 (L2 )2 ⋅ 2H2 O] ⋅ 2DMA ⋅ 2H2 O (SNNU-Bai77) and [Co4 (µ-F)2 (L)2 (L3 )2 ⋅ 2H2 O] ⋅ 2DMF ⋅ 2H2 O (SNNU-Bai78). With the 2D pore channels in SNNU-Bai76 and SNNU-Bai77 being tuned to the 1D pore channel in SNNU-Bai78, C3 H8 and C2 H6 adsorption uptakes are apparently improved and the IAST selectivities of C3 H8 /CH4 and C2 H6 /CH4 almost remain, which indicate that SNNU-Bai78 may be one potential separation material for the pipeline natural gas purification. These were further confirmed by the breakthrough experiments for the simulated pipeline natural gas (C3 H8 /C2 H6 /CH4 : 5/10/85 gas mixture) of three isostructural MOFs. Furthermore, GCMC simulations revealed that due to one of the pore channels blocked by Cl atoms in a couple of 3-chloro isonicotinic acid with the changed conformation as the pillar, the pore wall of the formed 1D pore channel in SNNU-Bai78 may interact with the adsorbed C3 H8 or C2 H6 molecule more strongly, for which more atoms of framework at the new adsorption site will interact with the adsorbed gas molecule by more intermolecular interactions. This was also evidenced by the increased binding energies, being consistent with the tuning of adsorption enthalpies for C3 H8 and C2 H6 gas molecules, and the reduced C3 H8 and C2 H6 gas diffusion coefficients in SNNU-Bai78. Very interestingly, this work is the first example of finely tuning the pore connectivity of MOFs toward strengthened host-guest interactions for the gas adsorption and separation.

Double-Walled Zn36@Zn104 Multicomponent Senary Metal-Organic Polyhedral Framework and Its Isoreticular Evolution.

Metal-organic polyhedral frameworks are attractive in gas storage and separation due to large voids with windows that can serve as traps for guest molecules. Introducing multivariant/multicomponent functionalities in them are ways of improving performances for certain targets. The high compatibility of organic linkers can generate multivariant MOFs, but by far, the diversity of secondary building units (SBUs) in a single metal-organic framework is still limited (no more than two in most cases). Here we report a new double-walled Zn36@Zn104 metal-organic polyhedral framework (HHU-8) with five types of topologically distinct SBUs and its isoreticular evolution to the Zn36@Zn136 counterpart (HHU-8s). Both MOFs are the first to be constructed with such high numbers of topologically distinct SBUs as well as topologically distinct nodes, and their formation and evolution provide new insight into SBU's controllability.

New Reticular Chemistry of the Rod Secondary Building Unit: Synthesis, Structure, and Natural Gas Storage of a Series of Three-Way Rod Amide-Functionalized Metal-Organic Frameworks.

Reticular chemistry and methane storage materials have been predominately focused on finite metal-cluster-based metal-organic frameworks (MOFs). In contrast, MOFs constructed from infinite rod secondary building units (SBUs), i.e., rod MOFs, are less developed, and the existing ones are typically built from simple one-way helical, zigzag, or (mixed)polyhedron SBUs. Herein, inspired by a recent unveiled structure of Zn6(H2O)3(BTP)4 and by means of an amide-functionalized preliminary single tricarboxylate, a subsequent mixed tricarboxylate, and dicarboxylate linkers, an intricate three-way rod MOF and the next three isoreticular three-way rod MOFs have been successfully realized, namely, 3W-ROD-1 and 3W-ROD-2-X (X = -OH, -F, and -CH3), respectively. The structural analyses disclosed that the four compounds were constructed from unprecedented three-way invariant nonintersecting trigonal rod-packing SBUs cross-linked via the noncovalent-interaction-driven self-assembly of pseudo hexacarboxylates with the original tricarboxylate or different functional ditopic linkers, resulting in cage-like pore geometries accessible via ultramicroporous apertures concomitant with the complex topology transitivity, namely, 18 42 and 18 44. Sorption studies show that the apparent surface areas of these materials are among the most highly porous materials for rod MOFs. Due to the presence of favorable pocket sites created by X, ketone, and proximal amide groups as revealed by Monte Carlo molecular dynamics (MCMD) computational calculations, the MOFs exhibit impressive methane storage working capacities, outperforming the well-known rod Ni-MOF-74 and representing the highest values among rigid rod MOFs.

Ligand-Conformer-Induced Formation of Zirconium-Organic Framework for Methane Storage and MTO Product Separation.

In pursuit of novel adsorbents with efficient adsorptive gas storage and separation capabilities remains highly desired and challenging. Although the documented zirconium-tricarboxylate-based metal-organic frameworks (MOFs) have displayed a variety of topologies encompassing underlying and geometry mismatch ones, the employed organic linkers are exclusively rigid and poorly presenting one type of conformation in the resultant structures. Herein, a used and semirigid tricarboxylate ligand of H3 TATAB was judiciously selected to isolate a zirconium-based spe-MOF after the preliminary discovery of srl-MOF. Single-crystal X-ray diffraction reveals that the fully deprotonated TATAB linker in spe-MOF exhibits two distinct conformers, concomitant with popular Oh and rare S6 symmetrical Zr6 molecular building blocks, generating an unprecedented (3,3,12,12)-c nondefault topology. Specifically, the spe-MOF exhibits structurally higher complexity, hierarchical micropores, open metal sites free and rich electronegative groups on the pore surfaces, leading to relatively high methane storage capacity without considering the missing-linker defects and efficient MTO product separation performance.

Single-Crystal Synthesis and Diverse Topologies of Hexanuclear CeIV-Based Metal-Organic Frameworks.

CeIV6-based metal-organic frameworks (MOFs) have gained increasing attention recently because of their diverse potential applications and similarity to prominent Zr-MOFs, e.g., the UiO-66 series. However, the reported CeIV6-based MOFs were all structurally determined by means of the powder X-ray diffraction technique, indicative of less practice and convenience. Herein, four single-crystalline CeIV6-based MOFs were successfully isolated and characterized by single-crystal X-ray diffraction, disclosing two series of topologically distinct isoreticular nets accompanied by nine-coordinated central CeIV ions, i.e., 8-connected hex and 12-connected fcu, respectively, in contrast to the previously reported sole fcu topology based on the combination of linear dicarboxylate ligands and a CeIV6 cluster associated with eight-coordinated central CeIV ions according to the UiO-66 structural model. Moreover, all four single-crystalline compounds exhibit permanent microporous porosities and a certain amount of gas uptake toward CO2, CH4, and H2.

Pure-Supramolecular-Linker Approach to Highly Connected Metal-Organic Frameworks for CO2 Capture.

A pure-supramolecular-linker (PSL) approach for the formation of metal-organic frameworks (MOFs) was initially given, which was demonstrated by syntheses of two highly connected and isostructural MOFs, {Fe3O(TPBTM6-)(Cl)(H2O)2}∞ (TPBTM = N,N',N″-tris(isophthalyl)-1,3,5-benzenetricarboxamide) (NJU-Bai52, NJU-Bai for Nanjing University Bai group) and {Sc3O(TPBTM6-)(OH)(H2O)2}∞ (NJU-Bai53). Very interestingly, they exhibit exceptional thermal stability, water stability, and highly selective CO2 capture properties. In particular, NJU-Bai53 with higher uptakes (2.74 wt % at 0.4 mbar and 298 K, 7.67 wt % at 298 K and 0.15 bar) and higher selectivity may be an excellent candidate for CO2 capture.

Solvents-Dependent Formation of Three MOFs from the Fe3O Cluster and 3,3',5,5'-Diphenyltetracarboxylic Acid and Their Selective CO2 Adsorption.

On the basis of the [Fe3(µ3-O)(COO)6] cluster and 3,3',5,5'-diphenyltetracarboxylic acid (H4BPTC), three novel metal-organic frameworks (MOFs), NJU-Bai25, NJU-Bai26, and NJU-Bai27 (NJU-Bai for Bai's group at Nanjing University ) with different (4,4,4,6)-, (4,4,4,4,4,6)-, and (4,4,6)-connected nets were obtained in different solvent systems, in which due to the steric hindrance of the coordinated solvents the conformations of BPTC gradually change from the planar to the torsional; thus, the pore sizes of those MOFs were also gradually narrowed. Interestingly, the MOFs show high thermal/chemical stabilities and selective CO2 adsorption: NJU-Bai27 exhibits larger CO2 uptake (5.0 and 13.8 wt %) at 298 K under 0.15 and 1 bar, whereas NJU-Bai26 has a higher selectivity for CO2/N2 (366).

Stable Amide-Functionalized Metal-Organic Framework with Highly Selective CO2 Adsorption.

A new amide-functionalized metal-organic framework (AFMOF) with the combined feature of highly selective CO2 adsorption and high thermal and chemical stability, [Sc3(µ3-O)(L)1.5(H2O)3Cl] n [NJU-Bai49; NJU-Bai for Nanjing University Bai's group, H4L = 5-(3,5-dicarboxybenzamido)isophthalic acid], was synthesized that exhibits 4.5 wt % CO2 uptake at 298 K and 0.15 bar and the highest selectivity for CO2/N2 (166.7) among all AFMOFs. Grand canonical Monte Carlo simulations further indicate that both the decorated amide group and the open metal site act as CO2 binding sites, which may contribute to its highly selective CO2 uptake.

The Quality of Spontaneous Adverse Drug Reaction Reports in China: A Descriptive Study.

Pharmacovigilance is important to monitor the safety of drugs. There are, however, problems with the quality of adverse drug reaction reports in China. This study aimed to analyze the quality of adverse drug reaction reports in China, identify the factors affecting it, and propose measures to improve it. In our study, the western province of Shaanxi, the central province of Hubei and the eastern province of Jiangsu were chosen as typical, and adverse drug reaction reports from these three provinces from 2015 to 2017 were systematically sampled. The sampling reports were scored and graded to assess their quality. The results showed that only 10.18% were considered high quality in a total of 3429 reports. There were statistically significant differences in quality by year, province, report type, report source, and occupation of the reporter (p < 0.001). Reports from Shaanxi were slightly poorer quality, and "new" and "serious" reports and those from pharmacists were higher quality. Five indicators were particularly poor quality: patient information, adverse drug reaction, reporter information, drug information and vigilance. In conclusion, the quality of adverse drug reaction reports in China still needs improvement. Factors affecting quality included timing, location, report type, report source, and reporter's occupation. It may be helpful to publicize the importance of monitoring adverse drug reactions and improve the knowledge of reporters.

Higher Symmetry Multinuclear Clusters of Metal-Organic Frameworks for Highly Selective CO2 Capture.

A new approach of finely tuning multinuclear clusters of metal-organic frameworks (MOFs) through symmetry-upgradingly isoreticular transformation was first presented and a bcu-type MOF, {[Cu4(µ4-O)Cl2(IN)4][CuCl2]}∞ (NJU-Bai35; NJU-Bai for Nanjing University Bai group), with cluster [Cu4(µ4-O)Cl2(COO)4N4] of higher symmetry compared to the pristine MOF, was successfully synthesized. The symmetry upgrading implemented on the inorganic part triggers the adjustment of channels in NJU-Bai35 to fit CO2 molecules, leading to a high CO2 adsorption capacity (7.20 wt % at ∼0.15 bar and 298 K) and high selectivity of CO2 over N2 and CH4 (275.8 for CO2/N2 and 11.6 for CO2/CH4) in NJU-Bai35. Breakthrough experiments further confirmed that NJU-Bai35 might be an excellent candidate for CO2 capture and natural gas purification.

Fine Tuning of MOF-505 Analogues To Reduce Low-Pressure Methane Uptake and Enhance Methane Working Capacity.

We present a crystal engineering strategy to fine tune the pore chemistry and CH4 -storage performance of a family of isomorphic MOFs based upon PCN-14. These MOFs exhibit similar pore size, pore surface, and surface area (around 3000 m2 g-1 ) and were prepared with the goal to enhance CH4 working capacity. [Cu2 (L2)(H2 O)2 ]n (NJU-Bai 41: NJU-Bai for Nanjing University Bai's group), [Cu2 (L3)(H2 O)2 ]n (NJU-Bai 42), and [Cu2 (L4)(DMF)2 ]n (NJU-Bai 43) were prepared and we observed that the CH4 volumetric working capacity and volumetric uptake values are influenced by subtle changes in structure and chemistry. In particular, the CH4 working capacity of NJU-Bai 43 reaches 198 cm3 (STP: 273.15 K, 1 atm) cm-3 at 298 K and 65 bar, which is amongst the highest reported for MOFs under these conditions and is much higher than the corresponding value for PCN-14 (157 cm3 (STP) cm-3 ).

The Utilization of Amide Groups To Expand and Functionalize Metal-Organic Frameworks Simultaneously.

A new stepwise ligand-elongation strategy by amide spacers is utilized to prepare isoreticularly high-porous metal-organic frameworks (MOFs), namely, quasi-mesoporous [Cu2 (PDBAD)(H2 O)]n (H4 PDBAD=5,5'-((4,4'-((pyridine-3,5-dicarbonyl)bis(azanediyl))bis(benzoyl))bis(azanediyl))diisophthalic acid; NJU-Bai22: NJU-Bai for Nanjing University Bai's group), and mesoporous [Cu2 (PABAD)(H2 O)]n (H4 PABAD=5,5'-((4,4'-((4,4'-((pyridine-3,5-dicarbonyl)bis(azanediyl))bis(benzoyl))bis (azanediyl))bis(benzoyl))bis(azanediyl))diisophthalic acid; NJU-Bai23). Compared with the prototypical MOF of [Cu2 (PDAD)(H2 O)]n (H4 PDAD=5,5'-(pyridine-3,5-dicarbonyl)bis(azanediyl)diisophthalic acid; NJU-Bai21, also termed as PCN-124), both MOFs exhibit almost the same CO2 adsorption enthalpy and CO2 selectivity values, and better capacity for CO2 storage under high pressure; these results make them promising candidate materials for CO2 capture and sequestration. Interestingly, this new method, in comparison with traditional strategies of using phenyl or triple-bond spacers, is easier and cheaper, resulting in a better ability to retain high CO2 affinity and selectivity in MOFs with large pores and high CO2 storage capacity. Additionally, it may lead to the high thermal stability of the MOFs and also their tolerance to water, which is related to the balance between the density of functional groups and pore sizes. Therefore, this strategy could provide new opportunities to explore more functionalized mesoporous MOFs with high performance.

Functionalization of Microporous Lanthanide-Based Metal-Organic Frameworks by Dicarboxylate Ligands with Methyl-Substituted Thieno[2,3-b]thiophene Groups: Sensing Activities and Magnetic Properties.

From a methyl-substituted thieno[2,3-b]thiophene dicarboxylate, three types of three-dimensional (3-D) microporous lanthanide-based metal-organic frameworks, {[Ln(DMTDC)1.5(H2O)2]·DEF}n (type I, Ln = Eu 1, Tb 2), {[Ln(DMTDC)1.5(H2O)2]·0.5DMF·0.5H2O}n (type II, Ln = Gd 3, Dy 4, Er 5), and {[Ln4(DMTDC)6(DMF)2]·0.5DMF·1.5H2O}n (type III, Ln = Er 6) (H2DMTDC = 3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylic acid, DEF = N,N'-diethylformamide, DMF = N,N'-dimethylformamide), have been solventhermally synthesized. Types I and II are isostructural, which exhibit 1-D triangular channels constructed by double-stranded rod-shaped {Ln(CO2)2}n chains. Type III demonstrates an intriguing framework with triple-stranded rod-shaped {Ln(CO2)3}n chains arranged along the (1,1,0) and (1,-1,0) axes and possesses two kinds of triangular channels along two axes, respectively. Immobilization of the Lewis basic sites of thiophene groups induced gas adsorption and sensing properties into these microporous frameworks. Complexes 5(Er) and 6(Er) display moderate adsorption properties toward N2 and CO2, and the Qst of CO2 are as high as 36.3 and 34.8 kJ mol(-1), respectively. Complexes 1(Eu) and 2(Tb) exhibit sensing properties toward nitrobenzene, acetone, and the Cu(2+) ion in both DMF and aqueous solution. Complex 3(Gd) shows a significant magnetocaloric effect with ΔSm = 24.3 J·kg(-1)·K(-1) at 3.0 K and 7 T. Complex 4(Dy) exhibits slow magnetic relaxation with the energy barrier Δ/kB of 48.29 K.

Finely Tuning Metal Ion Valences of [Fe3-xMx(µ3-OH)(Carboxyl)6(pyridyl)2] Cluster-Based ant-MOFs for Highly Improved CO2 Capture Performances.

Solvothermal reactions of different trinuclear precursors and 5-(pyridin-4-yl)isophthalic acid (H2L) successfully led to four anionic ant topological MOFs as Fe3-xMx(µ3-OH)(CH3COO)2(L)2·(DMA+)·DMF [M = Mn(II), Fe(II), Co(II), x = 0, 1, 2 and 3], namely, NJTU-Bai79 [NJTU-Bai = Nanjing Tech University Bai's group, Mn3(µ3-OH)], NJTU-Bai80 [Fe2Mn(µ3-OH)], NJTU-Bai81 [Fe3(µ3-OH)], and NJTU-Bai82 [Fe2Co(µ3-OH)], which possess the narrow pores (2.5-6.0 Å). NJTU-Bai80-82 is able to be tuned to the neutral derivatives [NJTU-Bai80-82(-ox), ox = oxidized] with M2+ ions oxidized to M3+ ones in the air and the OH- ions coordinated on M3+ ions. Very interestingly, selective CO2/N2 adsorptions of NJTU-Bai80-82(-ox) are significantly enhanced with the CO2 adsorption uptakes more than about 6 times that of NJTU-Bai79. GCMC simulations further revealed that neutral NJTU-Bai80-82(-ox) supplies more open frameworks around the -CH3 groups at separate spaces to the CO2 gas molecules with relatively more pores available to them after the removal of counterions. For the first time, finely tuning metal ion valences of metal clusters of ionic MOFs and making them from electrostatic to neutral were adopted for greatly improving their CO2 capture properties, and it would provide another promising strategy for the exploration of high-performance CO2 capture materials.

Fine-tuning pore size by shifting coordination sites of ligands and surface polarization of metal-organic frameworks to sharply enhance the selectivity for CO2.

Based upon the (3,6)-connected metal-organic framework {Cu(L1)·2H(2)O·1.5DMF}(∞) (L1 = 5-(pyridin-4-yl)isophthalic acid) (SYSU, for Sun Yat-Sen University), iso-reticular {Cu(L2)·DMF}(∞) (L2 = 5-(pyridin-3-yl)isophthalic acid) (NJU-Bai7; NJU-Bai for Nanjing University Bai group) and {Cu(L3)·DMF·H(2)O}(∞) (L3 = 5-(pyrimidin-5-yl)isophthalic acid) (NJU-Bai8) were designed by shifting the coordination sites of ligands to fine-tune pore size and polarizing the inner surface with uncoordinated nitrogen atoms, respectively, with almost no changes in surface area or porosity. Compared with those of the prototype SYSU, both the adsorption enthalpy and selectivity of CO(2) for NJU-Bai7 and NJU-Bai8 have been greatly enhanced, which makes NJU-Bai7 and NJU-Bai8 good candidates for postcombustion CO(2) capture. Notably, the CO(2) adsorption enthalpy of NJU-Bai7 is the highest reported so far among the MOFs without any polarizing functional groups or open metal sites. Meanwhile, NJU-Bai8 exhibits high uptake of CO(2) and good CO(2)/CH(4) selectivity at high pressure, which are quite valuable characteristics in the purification of natural gases.