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A novel fluorine-functionalized 2D covalent organic framework, with kgd topology and improved C2H2/CO2 separation over its fluorine-free counterpart, is reported.

As a highly promising candidate for hydrogen storage, crucial to vehicles powered by fuel cells, metal–organic frameworks (MOFs) have attracted the attention of chemists in recent decades. H2 uptak...

The unique structural advantage of metal-organic frameworks (MOFs) determines the great prospect and developability in gas adsorption and separation. Both ligand design and microporous engineering based on crystal structure are significant lever for coping with new application exploration and requirements. Focusing on the designable pore and modifiable frameworks of MOFs, this review discussed the recent advances in the field of gas adsorption and separation, and analyzed the host-guest interaction, structure-performance relations, and the adsorption/separation mechanism from ligand design, skeleton optimization, metal node regulation, and active sites construction. Based on the function-oriented perspective, we summarized the main research recently, and made an outlook based on the focus of microporous MOFs that require further attention in the structure design and industrial application.

A Co-doping core–shell shaped NiSe2 based catalyst (NixCo1−xSe2@NC) exhibits promising electrocatalytic activity for HER with a low overpotential of −143 mV at −10 mA cm−2, a small Tafel slope of 37.5 mV dec−1.

We present a controlled fabrication of selective ultrathin metal–organic framework (MOF) nanosheets as preassembling platforms, yolk–shell structured with a few-layered N-doped carbon (NC) shell-en...

An unexpected in-situ hydrolysis reaction occurred during the solvothermal reaction of N,N′-bis(4-carboxy-2-methylphenyl)pyromellitic di-imide) and Ba(NO3)2, and a novel porous Ba-MOF, [H2N(CH3)​2]0.5[Ba1.5(L)(DMA)]·1.5DMA·1.5H2O (UPC-70, H3L = 2-(4-carboxy-2-methylphenyl)-1,3-dioxoisoindoline-5,6-dicarboxylic acid, DMA = N,N-dimethylacetamide), was obtained on the basis of the partial hydrolysate. The as-synthesized 3D network with 1D open channels of different sizes (24 A and 10 A) contains abundant open metal sites after removal of solvents, which is conducive to the preferential adsorption of CO2. The subsequent gas sorption measurement reveals the high separation selectivity of UPC-70 for CO2/CH4 (15) and CO2/N2 (32) at ambient conditions, and GCMC theoretical simulation provides good verification of the experimental results, indicating that UPC-70 is a potential candidate for CO2 capture from flue gas and natural gas.

The structural diversity of three-dimensional (3D) covalent organic frameworks (COFs) are limited as there are only a few choices of building units with multiple symmetrically distributed connection sites. To date, 4 and 6-connected stereoscopic nodes with T

Solid-state transformations in metal-organic framework (MOF) systems are important phenomena and have led to the creation of new MOF structures. Solid-state transformations from interpenetrated to non-interpenetrated networks involving rearrangement of secondary building units (SBUs) in a single-crystal-to-single-crystal (SCSC) fashion have not been explored to date. Herein, we report the sequential, thermally stimulated solid-state transformations in a barium-organic framework ( UPC-600 ). The two-fold interpenetrated framework of UPC-600 is converted at 373 K to UPC-601 , a non-interpenetrated framework. This proceeds in a SCSC fashion and involves the rearrangement of two proximate rod-shaped SBUs in different nets to generate a new rod-shaped SBU. At 473 K, a continuous solid-state transformation involving a second rearrangement occurred, UPC-601 converted to UPC-602 by the rearrangement of the 1D rod-shaped SBU to a 2D layer SBU. This is the first example of such a thermally-driven stepwise transformation involving simultaneous cleavage and regeneration of multiple bonds. This result will enable detailed studies of solid-state transformations, and encourages a deep understanding of the role of solid-state transformations in the synthesis of MOF materials.

The design of MOFs with functionalized groups as well as suitable pore space plays a momentous part in gas adsorption and separation. Herein, a new Zn-MOF (Zn4(BTB-NH2)3·xsolvent, UPC-98, H3BTB-NH2...

Adsorptive separation of acetylene (C2H2) from carbon dioxide (CO2) promises a practical way to produce high-purity C2H2 required for industrial applications. However, challenges exist in the pore environment engineering of porous materials to recognize two molecules due to their similar molecular sizes and physical properties. Herein, we report a strategy to optimize pore environments of multivariate metal-organic frameworks (MOFs) for efficient C2H2/CO2 separation by tuning metal components, functionalized linkers, and terminal ligands. The optimized material UPC-200(Al)-F-BIM, constructed from Al3+ clusters, fluorine-functionalized organic linkers, and benzimidazole terminal ligands, demonstrated the highest separation efficiency (C2H2/CO2 uptake ratio of 2.6) and highest C2H2 productivity among UPC-200 systems. Experimental and computational studies revealed the contribution of small pore size and polar functional groups on the C2H2/CO2 selectivity and indicated the practical C2H2/CO2 separation of UPC-200(Al)-F-BIM.

A series of isostructural rare-earth metal–organic frameworks (RE-MOFs), namely {[RE(L-X)(H2O)]·2DMF}n (UPC-38, RE = Eu, Tb, X = H, F, Cl, NH2, CH3, OCH3; L = [1,1′:3′,1′′-terphenyl]-4,4′′,5′-tricarboxylic acid) have been successfully synthesized under solvothermal conditions. Single-crystal X-ray diffraction analysis shows that UPC-38 is an unprecedented three-dimensional (3D) (3,4,5)-czkf topological framework with one-dimensional (1D) chain secondary building units. Different functional groups can be attached to the ligand (L), and the effects of the different functional groups on the fluorescence intensity, emission wavelength and quantum yield of UPC-38 were systematically studied. It was found that the introduction of an amino group causes the emission wavelength to red shift significantly, while that of other groups causes slight effects on the emission wavelengths. UPC-38(Eu)-H and UPC-38(Tb)-H without modified functional groups in these twelve crystals exhibit the highest quantum yield ratios of 16.64% and 28.06%, respectively. Remarkably, by adjusting the ratio of Eu3+ to Tb3+ and the L-OCH33+ ligand with the strongest blue emission, a series of double-doped rare-earth metal–organic frameworks, UPC-38(EuxTb1−x)-OCH3 (0 ≤ x ≤ 1), are successfully acquired. The calculated CIE coordinates of UPC-38(Eu)-OCH3 and UPC-38(Tb)-OCH3 are (0.50, 0.28) and (0.23, 0.45), respectively. It is exciting that a white light emitting material, UPC-38(Eu0.34Tb0.66)-OCH3, can be successfully obtained through careful tuning of the Eu3+/Tb3+ ratio in the framework. The CIE coordinate is (0.335, 0.325), which is very close to the standardized value of (0.333, 0.333).

A series of cobalt and metal-free phthalocyanine ambipolar semiconductors, MPc[β/α-O(4-CF3-Ph)4] (M = Co, 2H) (1–4), are synthesized and fabricated into self-assembled microstructures. The Co[Pc(β/α-OPhCF3)4] (1 and 3) molecules formed one-dimensional (1D) nanoribbons (400–300 nm) with a larger width of 1 relative to 3, whereas the H2Pc[β/α-O(4-CF3-Ph)4] (2 and 4) molecules self-assembled into wider microbelts (5–4 μm) with 2 larger than 4, showing the effect of the M center and the substituent positions of the Pc rings on the dimensions of the microstructures. An increased crystallinity is revealed in the order of 4 < 3 < 2 < 1, resulting in an increased conductivity in the same order. Towards NO2 and NH3, both positive and negative current changes are found among the sensors 1–4, with the lowest limit of detection (LOD) as low as 3 ppb for NO2 and 420 ppb for NH3 from 1, while a positive current response to H2S is obtained only from 1 with a LOD of 100 ppb, respectively, achieving the best results for the room-temperature detection of NO2, NH3 and H2S gases based on all of the solution-processed phthalocyanine-based sensors reported so far. Accordingly, the sensor responses are dominated by both M-analyst interaction (M = Co, 2H) and conductivity among the sensors 1–4. In particular, different sensor arrays consisting of the sensor of 1 combined with one of the other three sensors of 2–4 are established. NO2, NH3 and H2S gases at ppb levels can be accurately identified by the combination of two parameters, namely current change direction and sensitivity.

The selective adsorption of APPT-Cd-MOF 1 for propyne, 2-butyne and phenylacetylene was confirmed by single-crystal analysis. In addition, the selective adsorption performance of Cd-MOF for C3H4/C3H6/C3H8 was investigated. The matching of the functionality and size/shape between porous materials and guest molecules clarified the specific recognition of 1 for linear alkyne molecules.

Covalent organic frameworks (COFs), a fast-growing field in crystalline porous materials, have achieved tremendous success in structure development and application exploration over the past decade. The vast majority of COFs reported to date are designed according to the basic concept of reticular chemistry, which is rooted in the idea that building blocks are fully connected within the frameworks. We demonstrate here that sub-stoichiometric construction of 2D/3D COFs can be accomplished by the condensation of a hexagonal linker with 4-connected building units. It is worth noting that the partially connected frameworks were successfully reticulated for 3D COFs for the first time, representing the highest BET surface area among imine-linked 3D COFs to data. The unreacted benzaldehydes in COF frameworks can enhance C2H2 and CO2 adsorption capacity and selectivities between C2H2/CH4 and C2H2/CO2 for sub-stoichiometric 2D COFs, while the reserved benzaldehydes control the interpenetrated architectures for the 3D case, achieving a rare non-interpenetrated pts topology for 3D COFs. This work not only paves a new avenue to build new COFs and endows residual function groups with further applications but also prompts redetermination of reticular frameworks in highly connected and symmetrical COFs.

Linker desymmetrization has been witnessed as a powerful design strategy for the discovery of highly connected metal-organic frameworks (MOFs) with unprecedented topologies. Herein, we introduce molecular pivot-hinge installation as a linker desymmetrization strategy to evolve the topology of highly connected rare-earth (RE) MOFs, where a pivot group is placed in the center of a linker similar to a hinge. By tuning the composition of pivot groups and steric hindrances of the substituents on various linker rotamers, MOFs with various topologies can be obtained. The combination of L-SO2 with C2v symmetry and 12-connected RE9 clusters leads to the formation of a fascinating (4,12)-c dfs new topology. Interestingly, when replacing L-SO2 with a tetrahedra linker L-O, the stacking behaviors of RE-organic layers switch from an eclipsed mode to a staggered stacking mode, leading to the discovery of an intriguing hjz topology. Additionally, the combination of the RE cluster and a linker [(L-(CH3 )6 )] with more bulky groups gives rise to a flu topology with a new 8-c inorganic cluster. The diversity of these RE-MOFs was further enhanced through post-synthetic installation of linkers with various functional groups. Functionalization of each linker with acidic and basic units in the mesoporous RE-based PCN-905-SO2 allows for efficient cascade catalytic transformation within the functionalized channels.

Two Co(II)-MOFs with different structures were successfully synthesized under the premise of designing two ligands containing alkynyl functional groups. Complexes 1 ([Co(TEPA)(TPT)2/3]·2DMF·H2O) and 2 ([Co(EPA)(TPT)]·1.5DMF·1.5H2O) show excellent luminescence properties. Meanwhile, as fluorescent sensors, complexes 1 and 2 exhibit selectivity and sensitivity for Fe3+ with the Ksv of 1.520 × 104 L/mol and 3.543 × 104 L/mol, which can rapidly detect nitroaromatic compounds in methanol and ethanol, especially for 2,4-NPH through fluorescence quenching with high quenching efficiency. In particular, the Ksv value of complexes 1 and 2 towards 2,4-NPH can reach up to 1.627 × 105 L/mol and 9.600 × 104 L/mol, demonstrating that complexes 1 and 2 are good candidates for the identification and detection of Fe3+ and nitroaromatic compounds.

Ethylene (C2H4) and propylene (C3H6) are important energy sources and raw materials in the chemical industry. Storage and separation of C2H4 and C3H6 are vital to their practical application. Metal–organic frameworks (MOFs) having adjustable structures and pore environments are promising candidates for C3H6/C2H4 separation. Herein, we obtained a Cu-based MOF synthesized by H3TTCA and pyrazine ligands. By adding different functional groups on the ligands within the MOFs, their pore environments are adjusted, and thus, the C3H6 storage capacity and C3H6/C2H4 separation efficiency are improved. Eventually, the fluoro- and methyl-functionalized iso-MOF-4 exhibits a better gas storage and C3H6/C2H4 separation performance compared with iso-MOF-1 (nonfunctionalized), iso-MOF-2 (fluoro-functionalized), and iso-MOF-3 (methyl-functionalized). A record-high C3H6 uptake of 293.6 ± 2.3 cm3 g–1 (273 K, 1 atm) is achieved using iso-MOF-4. Moreover, iso-MOF-4 shows excellent repeatability, and only 3.5% of C3H6 storage capacities decrease after nine cycles. Employing Grand Canonical Monte Carlo (GCMC) simulations, it is indicated that iso-MOF-4 preferentially adsorbs C3H6 rather than C2H4 at low pressure. Single-crystal X-ray diffraction on C3H6-adsorbed iso-MOF-4 crystals precisely demonstrates the adsorption positions and arrangement of C3H6 molecules in the framework, which is consistent with the theoretical simulations. Remarkably, gas sorption isotherms, molecular simulations, and breakthrough experiments comprehensively demonstrate that this unique MOF material exhibits highly efficient C3H6/C2H4 separation. Additionally, iso-MOF-4 also possesses efficient separation of C3H8/CH4 and C2H6/CH4, indicating its promising potential in storage/separation of light hydrocarbons in industry., Fine-tuning the pore environment through multifunctionalized ligand modification in an isoreticular Cu-MOF framework for optimal gas adsorption and separation is studied.

The structural diversity of highly connected metal-organic frameworks (MOFs) has long been limited due to the scarcity of highly connected metal clusters and the corresponding available topology. Herein, we deliberately chose a series of tritopic linkers with multiple substituents to construct a series of highly connected rare-earth (RE) MOFs. The steric hindrance of these substituents can be systematically tuned to generate various linker rotamers with tunable configurations and symmetries. For example, the methyl-functionalized linker (L-CH3) with C2 v symmetry exhibits larger steric hindrance, forcing two peripheral phenyl rings perpendicular to the central one. The combination of C2 v linkers and 9-connected RE6 clusters leads to the formation of a new fascinating (3,9)-c sep topology. Unlike Zr-MOFs exhibiting Zr6 clusters in various linker configurations and corresponding different structures, the adaptable RE6 clusters can undergo metal insertion and rearrange into new RE9 clusters when connected to an unfunctionalized linker (L-H) with C1 symmetry, giving rise to a new (3,3,18)-c ytw topology. More interestingly, by judiciously combining the linkers with both small and bulky substituents through mixed-linker strategies, an RE9-based MOF with an engaging (3,3,12)-c flg topology could be obtained as a result of continuous steric hindrance control. In this case, the two mixed linkers adopt configurations with moderate steric hindrances. Molecular simulation demonstrates that the combination of substituents with various steric hindrances dictates the resulting MOF structures. This work provides insights into the discovery of unprecedented topologies through systematic and continuous steric tuning, which can further serve as a blueprint for the design and construction of highly complicated porous structures for sophisticated applications.

Three cadmium(II) metal-organic frameworks (MOFs) based on tetracarboxylate ligands, namely [Cd2(TTTA)(DMF)3]·2DMF (1), [Cd2(TB)(H2O)4]·3DMF·H2O (2) and [Cd(TEB)0.5]·2DMF·4H2O (3) have been designed and synthesized. Complex 1 is a 2-dimensional (2D) 3,4-connected network with 3,4L13 topology, complex 2 features a 3-dimensional (3D) 3,4-connected tfa topology with a 2-fold interpenetrating structure and complex 3 has a 3D 4-connected dia topology with a 4-fold interpenetrating structure. Interestingly, 2 exhibits permanent pores and selective adsorption of CO2 over CH4. In addition, 2 shows fluorescence sensing of Fe3+ ion and rapid detection of nitroaromatic compounds (NACs) through fluorescence quenching.

The separation of ethylene (C2 H4 ) from a mixture of ethane (C2 H6 ), ethylene (C2 H4 ), and acetylene (C2 H2 ) at normal temperature and pressure is a significant challenge. The sieving effect of pores is powerless due to the similar molecular size and kinetic diameter of these molecules. We report a new modification method based on a stable ftw topological Zr-MOF platform (MOF-525). Introduction of a cyclopentadiene cobalt functional group led to new ftw-type MOFs materials (UPC-612 and UPC-613), which increase the host-guest interaction and achieve efficient ethylene purification from the mixture of hydrocarbon gases. The high performance of UPC-612 and UPC-613 for C2 H2 /C2 H4 /C2 H6 separation has been verified by gas sorption isotherms, density functional theory (DFT), and experimentally determined breakthrough curves. This work provides a one-step separation of the ternary gas mixture and can further serve as a blueprint for the design and construction of function-oriented porous structures for such applications.

The storage and separation of C2H2 and CO2 require specific porous materials having surfaces onto which C2H2 or CO2 molecular can be selectively adsorbed. Through the modification of a multifunctional ligand with −F, −Cl, −NH2, −CH3, −OCH3, and inorganic secondary building units (SBUs) with bipy-N ligands (dimethylamine, pyridine, 4-aminopyridine, and isonicotinic acid) based on a microporous Ni-MOF, the pore environment optimization is realized, achieving the enhancement of the adsorption and separation performances of C2H2 and CO2. The C2H2 uptakes vary from 178.4 to 130.1 cm3 g–1 and CO2 from 83.8 to 44.6 cm3 g–1 at 273 K and 1 atm. The 4-aminopyridine and dimethylamine modified UPC-110 has the highest C2H2/CO2 separation selectivity (5.1), further supported and explained via Grand Canonical Monte Carlo (GCMC) simulation and breakthrough experiments. Our work not only provides new porous materials for efficient C2H2 and CO2 storage but also contributes to the strategy on improving gas adsorption and se...

The functionalized modification of targeted porous metal–organic frameworks (MOFs) is important to improve the adsorption capacity of light hydrocarbon gases. Five isomorphic MOFs with different functional groups (F, Cl, NH2, CH3, and OCH3) are successfully synthesized by systematic functional modification of UMCM-151. By studying the adsorption properties of C2 and C3 hydrocarbons (C2H2, C2H4, C2H6, C3H6, and C3H8), it is found that the electron-withdrawing group functional UMCM-151-F and UMCM-151-Cl exhibit strong affinity for C2H2 (98.71 cm3 g–1 for UMCM-151-F and 90.29 cm3 g–1 for UMCM-151-Cl), while the electron-donating group functional UMCM-151-NH2, UMCM-151-CH3, and UMCM-151-OCH3 have strong affinity for C2H4 (97.89 cm3 g–1 for UMCM-151-NH2, 90.22 cm3 g–1 for UMCM-151-CH3 and 94.13 cm3 g–1 for UMCM-151-OCH3). The differences in affinity of electron effects for light hydrocarbon provide an experimental basis for porous MOFs to improve their light hydrocarbon storage capacity.

Developing effective and robust electrocatalysts that are applicable for different pH conditions is promising for variable industrial hydrogen evolution reaction (HER), whereas it remains challenging for designing proper materials and protocols. Herein, we have developed a two-step electrodeposition-hydrothermal strategy to construct heterostructured binary Ni-W sulfides nanosheets based on carbon fiber (NiWS/CF). The electrodeposited nickel oxides film on CF in the first step is sulfurized and concurrently incorporated with tungsten disulfide in the following hydrothermal process. Benefiting from synergistic advantages of bimetallic sulfides as well as interwoven nanosheets for efficient mass/charge transport, the NiWS/CF electrode shows excellent HER performances over a broad pH range from acidic (pH = 0), neutral (pH = 7) to alkaline (pH = 14) media. The NiWS/CF electrode also presents stability in long-term electrolysis in wide PH range for at least 12 h, and its interlaced nanosheets structure are well maintained. Our work may provide general and promising strategies to obtain inexpensive and efficient electrocatalysts for pH-universal hydrogen production.

A Co-based two-dimensional (2D) microporous metal-organic frameworks, [Co2(TMTA)(DMF)2(H2O)2]·NO3−·DMF (UPC-32) has been synthesized based on 4,4′,4′′-(2,4,6-trimethylbenzene-1,3,5-triyl)tribenzoic acid (H3TMTA). UPC-32 features a 2D microporous framework exhibits high adsorption of H2 (118.2 cm3/g, 1.05 wt%, at 77 K), and adsorption heat (Qst) of CO2 (34–46 kJ/mol). UPC-32 with narrow distance between layers (3.8 A) exhibits high selectivity of C3H6/CH4 (31.46) and C3H8/CH4 (28.04) at 298 K and 1 bar. It is the first 2D Co-MOF that showed selective separation of C3 hydrocarbon from CH4.

Based on the 5,10,15,20-tetra(cyanophenyl)porphyrin (CNTCPP) ligand, two supermolecule complexes formulated as [Cu(CNTCPP)]·2DMF (Cu-CNTCPP) and [Zn(CNTCPP)] (Zn-CNTCPP) have been synthesized and structurally characterized by single-crystal X-ray diffraction. Cu-CNTCPP features a 0 dimensional (0D) supramoleculer structure, whereas Zn-CNTCPP is a 2D structure. With coordination unsaturated points, Cu-CNTCPP exhibits electrocatalytic activity toward oxygen evolution reaction (OER) with low potential in 1.0 M KOH, generating a current density of 10 mA cm−2 at an potential of 1.66 V vs. RHE, which means it an efficient electrocatalytic material for OER.

Exploring active and stable electrocatalysts for the acidic oxygen evolution reaction (OER) is necessary to broaden the practical applications of proton exchange membrane electrolyzers. Unfortunately, the active sites of electrocatalysts for the acidic OER, which are the most powerful tool for designing and optimizing OER electrocatalysts, still remain ambiguous. Herein, we synthesize Ag doped Co3O4 with different atomic ratios of Co2+/Co3+ and investigate the effect of preferential exposure of Co2+ in Co3O4 on the acidic OER through systematic experiments for the first time. X-ray photoelectron spectroscopy is used to probe the atomic ratio of Co2+/Co3+ on the surface of Co3O4. The results demonstrate that Co3O4 richer in Co2+ shows the best acidic OER performance, and affords a current density of 10 mA cm−2 at an overpotential of 470 mV along with having a satisfactory stability in H2SO4 solution. Moreover, low-temperature calcination treatment is found to be an effective method to aid preferential growth of Co2+ on the surface of Co3O4, further making our synthesis process more practical and universal. Therefore, this work provides some insight into designing non-precious electrocatalysts for the acidic OER, by identifying active sites and offering a versatile modulation strategy on the preferential growth of real active sites.

A major goal of metal–organic framework (MOF) research is to adjust the structure and function for specific applications. It is highly desirable to develop new multifunctional MOF materials for selective guest molecule storage/separation and catalysis. Recent advances in the synthesis of MOFs have created new opportunities in this direction. Although many multifunctional MOFs have been synthesized to explore different applications, it is still a challenge to construct MOFs with high physicochemical stability for specific applications. In addition, most of the MOFs only have a microporous structure, which is not conducive to the transportation of substances and the entry of macromolecules, thus limiting the applications of these materials in macromolecular adsorption. Herein, we present three amino-functionalized InIII/AlIII/ZrIV-based MOFs with high physicochemical stability for multifunctional performances. The pore size of these MOFs varies from a few angstroms to the nanometre scale, and their specific surface areas and pore volumes gradually increase with the change of nodes. Further studies reveal that these MOFs are promising candidates as storage mediums for hydrogen (H2) and as separation agents for the selective removal of (C3Hn–C2Hn) from natural gas (NG). The mesoporous Zr-MOF can effectively enrich dye molecules to purify water, and the adsorption dynamics of a series of organic dyes shows that there are no size and charge-selective effects for the adsorption process. Furthermore, the catalytic efficiency and mechanism of Knoevenagel condensation reactions have also been studied in detail. Overall, the three versatile amino-functionalized MOFs highlight the advantages of metal–organic frameworks for designing host materials tailored for applications in hydrogen (H2) storage, light hydrocarbon adsorption/separation, water purification, and catalysis.

A barium(II) metal-organic framework (MOF) based on a predesigned amino-functionalized ligand, namely [Ba2(L)(DMF)(H2O)(NO3)1/3]∙DMF∙EtOH∙2H2O (UPC-33) [H3L = 4,4'-((2-amino-5-carboxy-1,3-phenylene)bis(ethyne-2,1-diyl))dibenzoic acid] has been synthesized. UPC-33 is a 3-dimensional 3,18-connected network with fcu topology with a rarely twelve nuclear Ba12(COO)18(NO3)2 cluster. Interestingly, UPC-33 shows permanent pores and high adsorption heat of CO2 (49.92 kJ*mol-1), which can be used as a platform for selective adsorption of CO2/CH4 (8.09). In addition, UPC-33 exhibits high separation selectivity for C3 light hydrocarbons with respect to CH4 (228.34, 151.40 for C3H6/CH4, C3H8/CH4 at 273k and 1 bar), as shown by single component gas sorption and selectivity calculations. Due to the existence of -NH2 groups in the channels, UPC-33 can effectively catalyze Knoevenagel condensation reactions with high yield and substrate size and electron dependency.

Due to the advantages of ultrahigh power density, long lifespan and easy integration with wearable and microscale electronics, micro-supercapacitors (MSCs) have attracted great interest in recent years. However, new high-performance electrode materials for such micro-electrochemical energy storage devices require deep excavation. Herein, we precisely synthesized a new 3D bulk MOF and new 2D ultrathin MOF nanosheets with a thickness of less than 10 nm, and utilized them as high-capacitance microelectrode materials for sophisticated all-solid-state MSC devices respectively. Notably, the MSCs based on MOF nanosheets displayed a high areal capacitance of 28.3 mF·cm−2, and a volumetric capacitance of 15.7 F·cm−3 at 0.2 mA·cm−2. Especially, our MSCs exhibited remarkable energy density of 8.7 mWh·cm−3 at a power density of 110.3 mW·cm−3, and excellent cycling lifespans with retention of 96.0% after 10,000 cycles, and all performances are better than the MSCs based on MOF bulks. This work provides a new way to further explore the inherent advantages of MOFs and stimulates the synthesis of advanced MOFs materials for application in microscale energy storage.

Three rigid, linear ligands, namely 2′,5′-dimethyl-[1,1′:4′,1′′-terphenyl]-4,4′′-dicarboxylic acid (H2L1), triphenyl-6,6′-dicarboxylic acid (H2L2), and 2,2′-bipyridine-5,5′-dicarboxylic acid (H2L3), were used for constructing metal–organic frameworks (MOFs) with Pb(II). With a similar nature of solvent conditions (DMF/EtOH, with different volumes' rates), four structurally diverse MOFs, namely, [Pb(L1)(DMF)] 1, [Pb(L1)(DMF)] 2, [Pb(L2)] 3, and [Pb3(L3)2(Cl−)2] 4, were synthesized and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, elemental analysis, and powder X-ray diffraction measurements. As the numbers of the central benzene ring contained in the ligands changed from three to two, the length of the ligands varied from 15.64 A to 10.89 A, and steric functional groups endowed the three ligands with more variations, such as a 1D zigzag chain of 1, a 2D wave-like layer of 2, a 3D Pb–O–C-based layer of 3, and a 3D Pb–O–Cl-based chain of 4. Solid-state photoluminescence studies were carried out for all the complexes at room temperature.

N-doped carbon-encapsulated transition metal selenides (TMSs) have garnered increasing attention as promising electrocatalysts for hydrogen evolution reaction (HER). Accurately regulating the electronic structure of these nanohybrids to reveal the underlying mechanism for enhanced HER performances is still challenging and thus requires deep excavation. Herein, a series of pomegranate-like Nix Sey @NC core-shell nanohybrids (including Ni0.85 Se @ NC, NiSe2 @NC, and NiSe@NC) through controllable selenization of a Ni-MOF precursor is reported. The component of the nanohybrids can be fine-tuned by tailoring the selenization temperature and feed ratio, through which the electronic structure can be synchronously regulated. Among these nanohybrids, the Ni0.85 Se @ NC exhibits the optimum pH-universal HER performance with overpotentials of 131, 135, and 183 mV in 0.5 m H2 SO4 , 1.0 m KOH, and 1.0 m PBS, respectively, at 10 mA cm-2 , which are attributed to the increased partial density of state at the Fermi level and effective van der Waals interactions between Ni0.85 Se and NC matrix explained by density functional theory calculations.

Four metal–organic complexes [Ni(HET)(phen)(H2O)]·(HET)·H2O (1), [Cu(HET)(phen)(H2O)]·1.5H2O (2), [Cu2(HET)2(bipy)1.5(H2O)]·15DMF·2H2O (3), and [Cd2O(HET)2(bipy)(H2O)]·2H2O·EtOH (4) (HET = 1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid, phen = 1,10-phenanthroline, bipy = 4,4′-bipyridine) have been synthesized via hydro- or solvothermal reactions. It was found that complexes 1 and 2 are two-dimensional (2D) structures built from discrete complexes via the typical intermolecular interactions, and there was a closed loop built from the lattice water and carboxylate groups in 1 through intramolecular hydrogen bonds. Complex 3 exhibits three-dimensional (3D) structure with 5-connected bnn hexagonal BN topology. Complex 4 features a non-interpenetrating sql 2D coordination network, which is further linked into a 3D structure by C–H···Cl weak interaction. The properties of magnetism, fluorescence, and electrochemistry have also been investigated in this paper.

An anionic metal-organic framework, H3[(Mn4Cl)3L8]⋅30H2O⋅2.5 DMF⋅5 Diox (UPC-15), was successfully prepared by the reaction of MnCl2 with tris(p-carboxylic acid)tridurylborane (H3 L) under solvothermal conditions. UPC-15 with wide-open pores (∼18.8 Å) is constructed by packing of octahedral and cuboctahedral cages, and exhibits high gas-sorption capabilities. Notably, UPC-15 shows selective adsorption of cationic dyes due to the anion framework. Moreover, the catalytic and magnetic properties were investigated, and UPC-15 can highly catalyze the cyanosilylation of aromatic aldehydes. UPC-15 exhibits the exchange of metal ions from Mn to Cu in a single-crystal-to-single-crystal manner to generate UPC-16, which could not be obtained by the direct solvothermal reaction of CuCl2 and H3L. UPC-16 exhibits similar properties for gas sorption, dye separation, and catalytic activity. However, the magnetic behaviors for UPC-15 and UPC-16 are distinct due to the metal-specific properties. Below 47 K, UPC-15 exhibits a ferromagnetic coupling but UPC-16 shows a dominant antiferromagnetic behavior.

Five lanthanide metal–organic frameworks, [Ln(L)(H2O)(NMP)]·1.5H2O (Ln = Ce (1), Pr (2); H3L = 1,3,5-tris(4-carboxyphenyl-1-ylmethyl)-2,4,6-trimethylbenzene), and [Ln2(L)2(H2O)3]·2H2O (Ln = Eu (3), Tm (4), Yb (5)), have been synthesized and characterized. Complexes 1–5 exhibit similar 1D channels through the linkage of Ln-carboxylate chains with the backbones of H3L ligands. The channels for complexes 1 and 2 are occupied by coordinated NMP molecules. 3 shows potential application for the luminescence sensing of small organic molecules. Moreover, 5 exhibits selective adsorption of CO2 over N2 and CH4 and catalytic activities toward the cyanosilylation reaction.

Mesoporous alumina with different morphologies was synthesized via thermal decomposition of the Al-based metal–organic frameworks (Al-MOFs) MIL-110 and MIL-100, in which Al-MOFs were used as the Al source and precursor. The hexagon rod-shaped and octahedron-shaped alumina products with morphology retained from their precursors were obtained and characterized. The results show that the construction of Al-MOFs, especially the aluminium building units plays a key role in the textural structure of the obtained alumina products. Besides, the differences in textural properties as well as the possible formation mechanism of the final alumina products are well explained by taking into account thermal behaviour and intrinsic structure features, especially the aluminium building units, of the Al-MOFs precursors. This work presents an easy new method to produce alumina with tailored morphology, tunable texture and microstructure, which is also an operational method fit for other metal oxide materials.

Three new metal–organic frameworks (MOFs) constructed from terphenyl-3,3′′,5,5′′-tetracarboxylic acid (H4ptptc) and zinc nitrate, [Zn2(ptptc)(DMF)3]·4H2O·5.5DMF (1), [Zn2(ptptc)(DMA)(H2O)]·2.5H2O·3.5DMA (2) and [Zn(ptptc)0.5(H2O)]·DMF·DMA (3), have been obtained and characterized. All the complexes exhibit 3D 4-connected networks with different topologies involving diamond (dia, for 1), lonsdaleite (lon, for 2) and Nbo (for 3), which emanate from the different reaction solvents (DMF, DMA and mixture of DMF/DMA (1 : 1), respectively). The results of photoluminescence properties show that the three complexes can be act as potential luminescent probes or sensors for detecting small organic molecules and toxic substances.

Due to their tunable structure and porosity, metal–organic frameworks have provided a new platform for fluorescence sensing and adsorption/separation of gas or organic molecules. Many studies have focused on sensing metal ions, anions, or organic molecules through fluorescence quenching or enhancement of MOFs, but studies on pH-fluorescence sensors are seldom reported. Furthermore, highly solvent-dependent adsorption and degradation of dye molecules based on functional MOFs has not been explored to date. In this study, we describe a multifunctional Eu MOF, [H3O][Eu3(HBPTC)2(BPTC)(H2O)2]·4DMA (UPC-5, UPC = China University of Petroleum [East China]) based on a tetracarboxylate ligand. The luminescence intensity of UPC-5 is strongly correlated with the pH value in the pH range from 7.5 to 10.0, and a linear relationship between pH value and fluorescent intensity is observed. Another attractive property of UPC-5 is that its Li-exchanged form, Li-UPC-5, possesses solvent-dependent adsorption and degradation of rhodamine B. The highly efficient degradation or decolorization of rhodamine B with long-term stability and activity gives Li-UPC-5 a potential advantage in treating rhodamine B pollution.

This work presents the construction of a porous lead-organic framework (UPC-10) with large channels of ∼24 A. UPC-10 shows efficient adsorption of I2 and selective adsorption of some dyes containing the SO3− group. After the adsorption of dyes, UPC-10 exhibits a CO2 gas uptake ability. Furthermore, UPC-10 could be transformed into PbS in a H2S atmosphere, and the derived PbS manifests N2 and CO2 uptake abilities.

Two 2-fold interpenetrating metal–organic frameworks based on 1,3,5-tris[2-(4-carboxyphenyl)-1-ethynyl]-2,4,6-trimethylbenzene (H3LMe), [Mn3(LMe)2(DMF)4(H2O)]·1.5DMF·3.5H2O (1) and [Cd3(LMe)2(DMF)][Cd3(LMe)2(DMF)2(H2O)]·5DMF·3.5H2O (2), have been synthesized by using rigid trigonal H3LMe and nitrate under solvothermal conditions. Complex 1 displays a three-dimensional open framework with rare (3,6)-connected 2-nodal sit topology, whereas complex 2 features a new (3,3,6)-connected topology. Both 1 and 2 are blue fluorescent, and the magnetic measurement of 1 indicates that metal centers within the trinuclear cluster exhibit antiferromagnetic coupling interactions. Significantly, although complexes 1 and 2 have similar total solvent-accessible volumes, 2 demonstrates a higher Brunauer–Emmett–Teller surface area than that of 1, further indicating the influence of pore structure on gas absorption.

Successful encapsulation of phosphotungstic acid (PTA) within the nanocages of MIL-101 has been achieved via “ bottle around ship ” approach under static condition. XRD, FT-IR, 31 P MAS NMR, N 2 adsorption, SEM–EDS and XRF confirm the incorporation and well-distribution of PTA in both middle and large cavities of the MIL-101. SEM, XRD and TEM reveal the dominant crystal shapes of high loading PTA@MIL-101 are a monolithic and the adjacent lattice planes of MIL-101 are larger due to the addition of PTA. The host–guest composite materials PTA@MIL-101 containing 17–50 wt.% of PTA have been obtained and demonstrate an excellent catalytic performance in the oxidative desulfurization process of the refractory sulfur-containing compounds. This is the first example of the application of MIL-101 or PTA@MIL-101 composite materials in oxidative desulfurization. The reactivity of the sulfur-containing compounds follows the order DBT > 4,6-DMDBT > BT. In four consecutive reaction cycles, the catalyst recovery is in excess of 71%, while the DBT conversion slightly decreases.

Crystallizations of tris(2-carboxyethyl)isocyanuric acid (H3tci) without or with N-heterocyclic organic molecules result in three distinct supramolecular complexes, [(H3tci)] (1), organic salt [(Hma)+·(H2tci)−] (2) and cocrystal [(H3tci)·(bipy)1.5] (3) (ma = melamine, bipy = 4,4′-bipyridine). In the absence of N-heterocyclic organic molecules, three 2-carboxyethyl arms of H3tci show a cisanti–cisanti–transanti conformation. The H3tci molecules are extended to a 2D 44-sql net via O–H⋯O hydrogen bonds. However, in the presence of ma or bipy, the conformation of the 2-carboxyethyl arms of H3tci in both 2 and 3 is transformed to cisanti–cisanti–cisgauche induced by cocrystallized N-heterocyclic organic molecules. In 2, ma plays a crucial role in the formation of O–H⋯N, N–H⋯O and O–H⋯O hydrogen bonds which direct the binary species to form the 2D double-layer structure containing 24-membered supramolecular macrocycles. Complex 3 is a 1D chain based on a [(H3tci)2·(bipy)2] 42-membered macrocycle incorporating the carboxyl–pyridyl H-bonding supramolecular synthons, which are extended by another bipy molecule to form the 1D chain. The 1D chains are further extended by means of a C–H⋯O non-classic hydrogen bond to form the resulting 2D layer containing three kinds of macrocycles. The 2D layers are packed into a 3D framework through π⋯π interaction between the triazinyl and pyridyl rings. Based on the structural analysis, we found that the conformation of H3tci could be modulated by introduction of the cocrystallized N-heterocyclic organic molecules. Moreover, the thermal stabilities of 2 and 3 are discussed.

Three lanthanide–organic frameworks have been solvothermally synthesized and characterized. Complex 1 {[Pr2(bbda)(OH)2(H2O)6]·12H2O}n (H4bbda = 5,5′-(2,4,6-trimethyl-1,3-phenylene)bis(methylene)bis(oxy)diisophthalic acid) is a 3D porous framework belonging to a 2-nodal net with the ssa topology. The coordinated formate ligand from in situ hydrolyzation of dmf binds metal centers to generate rigid rod-shaped SBUs (secondary building units) in both complexes 2 and 3, [Ln(HCOO)(L1)(dmf)]n (Ln = Er (2), Tm (3), H2L1 = 2,2′-(2,3,5,6-tetramethyl-1,4-phenylene) bis(methylene)bis(sulfanediyl)dibenzoic acid, dmf = N,N′-dimethylformamide). The flexible ligand H4bbda in complex 1 exhibits syn conformation, while the flexible ligand H2L1 in complexes 2 and 3 adopts anti conformation. The anti L1 ligand links the rod-shaped SBUs to give 2 and 3 3D network with the rtl topology.

Single-crystal-to-single-crystal (SCSC) transformations, which involve cooperative movement of atoms in the solid state, have received much attention from chemists. Through SCSC transformation, new complexes, which may not be obtained under conventional conditions, can be obtained in high yield. The SCSC transformation was first reported as a photoreaction in organic complexes, which could be considered as a new organic synthetic method. Solid-state photochemical [2+2] cycloadditions of organic molecules have been well studied. Recently, SCSC transformation has been extended to other complexes, such as metal complexes and coordination polymers (or metal–organic frameworks). In the past decades, many metal–organic frameworks (MOFs) that undergo SCSC transformation have been reported. Most of these reports describe the sliding of layers or breathing of 3D porous MOFs through solvent exchange. SCSC transformations involving breaking and forming bonds in the solid state remain quite rare. The MacGillivray and Foxman groups attained considerable success in solid-state photodimerization of organic groups mediated by metals. Converting a finite metal complex into an infinite coordination network was also reported by the groups of MacGillivray and Vittal. The reported topochemical dimerizations of metal complexes involve the organization of two double or triple bonds in the solid state: the geometric criteria are very important for such SCSC reactions. However, the coordination geometry of the metal ion remains unchanged in these topochemical dimerizations. More recently, zur Loye and co-workers described a 3D cobalt–organic framework exhibiting reversible shrinkage and expansion involving a change in the cobalt coordination geometry through SCSC transformation induced by the removal and re-absorption of guest molecules. Studies on the change in the metal coordination geometry caused by the removal and addition of ligands from the framework itself through SCSC transformation remain less common. Herein, we describe a new type of SCSC dimerization of a mononuclear copper complex, specifically, thermally induced head-to-tail dimerization involving the formation of a new Cu Oligand bond and a change in the metal coordination geometry. The transformation induced a color change from blue to green, which was caused by the change in the copper coordination geometry (Scheme 1). Interestingly, the trans

The solvothermal reaction of Nd(NO3)3·6H2O and 5-amino-2,4,6-triiodoisophthalic acid (H2atiip) in DMF/ethonal/H2O (5:2:1) in the presence of pyridine gave rise to a new open neodymium−organic framework having the NbO structure type, [Nd(HCOO)(atiip)(DMF)2]·DMF·H2O (1). Complex 1 can keep its diffraction pattern even after being heated to 200 °C.

Two 1D coordination polymers with a 1D zigzag and a helical chain, respectively, have been solvothermally synthesized. The different coordinated small molecules on the cadmium ion have significant influences on the formation of different architectures. Due to the existence of supramolecular interactions between the helices in complex 2, the same chirality is preserved, resulting in a chiral architecture. By introducing a chiral molecule as cosolute, the bulk homochiral crystallization from achiral precursors for 2 can be achieved.