By regulating secondary building units and inducing multiplicate metal–ligand interactions, an unstable anionic framework MOF-Mn4Cl is structurally modified into a robust neutral framework MOF-Mn4. Although possessing same network topology, MOF-Mn4 shows a high BET surface area of 1718 m2/g, which is about an 8 times enhancement over MOF-Mn4Cl.

By using the net-to-net assembly strategy and HSAB interaction principle, a zeolitic metal–organic framework (FJI-Y3) with GIS topology is synthesized and derived from the tetrahedral crosslinking of interpenetrating dia nets. FJI-Y3 has a stable framework structure (at 280 °C) with an aperture of 6.7 Å and a high Cu+ density of 1.14 Cu+ nm−3. The activated sample FJI-Y3-ht exhibits very high D2 (250.1 cm3 g−1) and H2 (232.5 cm3 g−1) uptakes at 77 K and 1.06 Bar, as well as a C2H2 uptake of 147.8 cm3 cm−3 at 298 K and 1.06 bar. Furthermore, n-C4H10/i-C4H10 adsorption selectivity in excess of 84 for FJI-Y3-ht indicates its outstanding sieving properties for meeting the industrial challenge of n-C4H10/i-C4H10 separation.

•First report of Yb based MOF catalysts for the chemical fixation of CO2.•These MOFs contain uncommon Yb5 cluster and present unprecedented M12L8-cages.•These MOFs show highly selective CO2 adsorption and high-density Lewis acid sites.•These MOFs exhibit catalytic activities at ambient temperature and pressure.Two porous metal-organic frameworks (MOFs) incorporating pentanuclear Yb(III) clusters and pyridyl-supported tetracarboxylates or pyridyl carboxylic acid-supported tetracarboxylates, Yb-DDPY and Yb-DDIA, are presented, in which the pentanuclear Yb(III) cluster shows uncommon trigonal bipyramidal geometry. Furthermore, the pentanuclear Yb(III) clusters are extended by tetracarboxylates to form a 3D porous framework with uniform M12L8-cages constructed by 12 pentanuclear Yb(III) clusters and 8 tetracarboxylates with the size of ca. 20 Å × 17 Å. Their highly CO2 uptake capacity and the existence of Lewis acidic sites make these MOFs promising catalysts for the chemical conversion of CO2. These MOFs demonstrate good catalytic activities and recyclability in the cycloaddition of CO2 and epoxides at 60 °C under 1.0 MPa pressure or at room temperature and atmospheric pressure. In addition, the synergistic effect of the Brønsted acidic –COOH groups and the Lewis acidic Yb(III) sites makes Yb-DDIA exhibit higher catalytic activity towards the cycloaddition of CO2 and epoxides.Download high-res image (116KB)Download full-size image

•Coordination-assisted method was proposed for facile linking of energy donor and acceptor.•FRET-based probe improves the detection selectivity and further discriminate Fe3+ from Al3+ with different ratiometric fluorescence responses.•The probe showed good sensitivity with 166-fold fluorescence variation in the ratios I583/I502 before and after addition of Fe3+.Here we report a facile coordination-assisted method to construct a FRET-based probe that shows ratiometric detection of metal ions with improved selectivity. Probe 2 exhibits good sensitivity and selectivity towards the Fe3+ and Al3+ over other cations in aqueous acetonitrile solution. Probe 1 can be formed in situ by a convenient addition of Salen-Zn complex, which can further discriminate the Fe3+ from Al3+ with different ratiometric fluorescence responses.

The sharply rising level of atmospheric carbon dioxide resulting from anthropogenic emissions is one of the greatest environmental concerns nowadays. Capture and storage of carbon dioxide (CCS) from coal- or gas-burning power plants is an attractive route to reducing carbon dioxide emissions into the atmosphere. Porous organic polymers (POPs) have been recognized as a very promising candidate for carbon dioxide capture due to their low density, high thermal and chemical stability, large surface area, tunable pore size and structure, and facilely tailored functionality. In this review, we aim to highlight the POPs for CO2 capture and summarize the factors influencing CO2 capture capacity, such as surface area and pore structure, swellable polymers, heteroatomic skeleton and surface functionalized porous organic polymers.

Herein, an unprecedented monomeric bowl-like coordination complex, Ti12PgC3 (PgC3 = C-propylpyrogallol[4]arene), has been successfully synthesized. To the best of our knowledge, Ti12PgC3 not only presents the first pyrogallol[4]arene-based titanium coordination complex, but also the highest nuclearity titanium coordination complex in the metal–calixarene system. In addition, this titanium coordination complex can effectively degrade the methylene blue (MB) dye under sunlight.

To better understand the structure–catalytic property relationship, a platform of urea-containing MOFs with diverse topologies as hydrogen-bonding (H-bond) catalyst has been well established in the present work. During the construction of MOFs, we proposed a new strategy called the isoreticular functionalization approach in which the desired topological net is first considered as a blueprint, and then two predesigned functionalized polydentate ligands link to four different metal clusters by de novo routes to achieve the MOFs with expected pore structure and catalytic sites. By means of this strategy, we successfully synthesized four programmed MOFs (named as URMOF-1–4) with diverse topologies, pore morphologies, and sizes and distribution of active sites. Subsequently, we systematically investigated the Friedel–Crafts reactions of 1-methylpyrrole or 1-methylindole with nitroalkene derivatives with diverse sizes to assess the catalytic properties of the above-mentioned URMOFs. These four URMOFs can act as reusable H-bond catalysts and show varied catalytic capacities and size-selectivity properties. Most significantly, the open morphologies of pores, large channels in the framework, and effective distribution of active sites on the wall of the channel are proved to facilitate catalysis. This urea-containing MOF catalytic platform provides new insight into the catalytic properties of MOFs with the same kind of active sites but diverse topologies, pore morphologies, and sizes and distributions of catalytic sites.

•A high surface area host material PPN-13 was used in lithium–sulfur battery.•The host material PPN-13 exist vast nano-porous 3D diamond-cage structure.•The host material can efficient suppress the diffusive of polysulfide.•The unique host material impregnated sulfur present excellent electrochemical performance.Lithium–sulfur battery is one of the most promising energy storage systems for its high specific capacity. However, commercial development of lithium–sulfur batteries is severely hindered by the cathode host materials. To tackle this issue, we synthesized a new host material, high surface area, three-dimensional (3D) diamond-cage porous polymer frameworks PPN-13, to construct sulfur electrode by impregnating sulfur into its nano-pores. The PPN-13-S cathode deliveries a specific discharge capacity up to 606.4 mA h/g over 100 cycles at 0.1 C with a high coulombic efficiency. It demonstrates that the 3D porous structure PPN-13 as host material shows the high performance and a remarkable positive effect on the capacity retention as cathode materials in lithium–sulfur batteries. Due to the unique features of the material, our research provides a new type of materials for tailoring cathode materials in lithium–sulfur batteries.

Transferring the solution-state chemistry of organic-based molecular switches (OMS) into the solid state usually faces several fatal problems, such as spatial confinement or inefficient conversion. As a result, their switching behavior usually cannot be maintained. Herein, we report a redox-switchable metal–organic framework (MOF) that can undergo a reversible single-crystal-to-single-crystal (SCSC) transformation through a hydroquinone/quinone redox reaction. The redox-triggered transformation is quantitatively reversible while maintaining the crystallinity of the MOF scaffold. In addition, the transformation occurs gradually in the MOF backbone and from the outsurface of MOF to the inside. This study represents a general strategy to enable efficient conversion of the functionality of an OMS from solution into solid state, by incorporation of OMS into the framework of MOF. Furthermore, the material exhibits interesting changes in spectroscopic properties through reversible SCSC transformation and, thus, may be a starting point for the use of such materials in memory storage or redox-based electronic devices.

A series of porous hyper-cross-linked polymers with excellent physiochemical stability have been designed and prepared facilely through template-free Friedel–Crafts alkylation reactions between benzene/biphenyl/1,3,5-triphenylbenzene as co-condensing rigid aromatic building blocks and 1,3,5-tris(bromomethyl)benzene or 1,3,5-tris(bromomethyl)-2,4,6-trimethylbenzene as cross-linkers under the catalysis of anhydrous AlCl3 or FeCl3. The systematic study of gas uptake ability shows that anhydrous AlCl3 is a much more effective catalyst than anhydrous FeCl3. The synthesized polymers are thermally stable and are predominantly microporous with high surface areas up to 1783 m2 g−1. In addition, they exhibit high H2 and CO2 uptake capacity/selectivity. Among these materials, C1M3-Al has the highest H2 uptake capacity at 77 K and 1 bar (19.1 mg g−1) and CO2 uptake capacity at 273 K and 1 bar (181 mg g−1); the best CO2/N2 (15/85) selectivity calculated by IAST at 273 K and 1 bar belongs to C1M2-Al (32.3). Moreover, the synthesis route exhibits cost-effective advantages, which are essential for scale-up preparation, thus showing great potential for clean energy applications.

Herein, we report the targeted synthesis and solid state assembly of a novel triazine-based [4+6] organic molecular cage. The tetrahedral cage features a large cavity (∼2070 Å3), and after desolvation, the resultant material exhibits a high Brunauer–Emmett–Teller surface area of 1181 m2 g−1 and also features selective adsorption of CO2 over N2.

Herein, two stable lead(II) molecular-bowl-based metal–organic frameworks and their micro- and nanosized forms with open metal sites were presented. These materials could act as Lewis acid catalysts to cyanosilylation reaction. Moreover, the catalytic performances are size-dependent, with the catalyst with nanosized form being 1 order of magnitude more efficient than those with micro- and millisized forms.

A luminescent metal–organic framework was assembled by using 3,3′-((6-hydroxy-1,3,5-triazine-2,4-diyl)bis(azanediyl))dibenzoic acid and Zn(II), which exhibits a 2D layer architecture, and the adjacent layers are further stacked via hydrogen-bonding and N···N van der Waals interactions to form a 3D supramolecular framework. This material can be used as fluorescent probe of K+ ion.

A dual-functional complex with the formula Cd2(L)(DMF)2(H2O)2 (L = 2,3′,5,5′-biphenyl tetracarboxylic acid) has been successfully synthesized under solvothermal conditions and characterized by thermogravimetric analyses, IR spectroscopy, X-ray powder diffraction and single crystal X-ray diffraction. This material can selectively sense Zn2+ and Fe3+ ions over mixed metal ions through fluorescence enhancement and quenching, respectively. The cyanosilylation of aldehydes reaction studied used activated complex as a catalyst; the results showed that this complex with Lewis acid sites can act as a stable heterogeneous catalyst.

Four new coordination polymers, {[Cd2(L)2·H2O]·4DMF·14H2O}n (1), {[Cd (L)]·2DMF·6H2O}n (2), {[Zn2(L)2]·4DMF·5H2O}n (3) and {[Cu (L)]·2DMF}n (4) (H2L = 2,5-bis((4H-1,2,4-triazol-4-yl)carbamoyl)terephthalic acid), have been synthesized under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction. All of them exhibit three-dimensional structures possessing one-dimensional channels filled with solvent molecules. 1 is a 3D framework with large 1D channels (6.60 × 8.56 Å2) filled with free DMF molecules and the 3D structure of 1 is a new (4, 8) network with Schläfli symbol {416.612}{44.62}2. 2 and 3 with different metal centers have similar structure except for the numbers of free water molecules. They both feature a (4, 4)-connected 3D network of {65.10} {65.8} topology with left- and right-handed helical chains along b-axis. While 4 is a 3D framework with typical CdSO4 topology. In addition, 1–3 show strong fluorescent emissions at room temperature, which can be assigned to the ligand-to-ligand charge transfer (LLCT) emissions.Four new metal–organic frameworks display interesting 3D structures have been synthesized based on a novel organic ligand (H2L) involving both 1,2,4-triazole and carboxylic groups under solvothermal conditions. Compounds 1–3 display intense fluorescent emissions at 435, 444 and 445 nm, respectively.

Head-on polymerization of tetrahedral monomers inherently imparts interconnected diamond cages to the resulting framework with each strut widely exposed. We have designed and synthesized a series of 3,3′,5,5′-tetraethynylbiphenyl monomers, in which the two phenyl rings are progressively locked into a nearly perpendicular position by adding substituents of different size at 2, 2′, 6, and 6′ positions, as evident from single crystal structures. Computational simulation suggests that these monomers, though not perfectly regular tetrahedra, could still be self-polymerized into three-dimensional frameworks with the same topology. Indeed, five porous polymer networks (PPNs) have been successfully synthesized with these newly designed monomers through Cu(II)-promoted Eglinton homocoupling reaction. Among them, PPN-13 shows exceptionally high Brunauer–Emmett–Teller (BET) surface area of 3420 m2/g. The total hydrogen uptake is 52 mg/g at 40 bar and 77 K, and the total methane uptake is 179 mg/g at 65 bar and 298 K.

The current study describes the first in situ synthesis and characterization of a new family of cationic coordination tetrahedra of both the V4F4 and V4E6 type, which are constructed by a new building block based on a trinuclear zirconocene moiety and the dicarboxylate or tricarboxylate anions.

A 2-fold interpenetrated microporous MOF [Ni2(C2O4)(L)2]n·6nH2O (HL = 4,2′:4″,2′-terpyridine-4′-carboxylic acid) (1) was synthesized and structurally characterized. 1 has obvious 1D channels along the crystallographic a and c axes with a pore size of 5.7 to 6.9 Å. Topological analysis shows that the framework of 1 can be interpreted as a (3,4)-connected net with point symbol (63)(65·8). 1 exhibits high water and thermal stability, which is demonstrated by TGA, PXRD, and VT-PXRD. Additionally, the high temperature structure of 1′ (433 K) undoubtedly demonstrates the stability of the framework. More importantly, 1 shows high selectivities for CO2 over N2, H2, and CH4 at low pressure and 273 K.

Two dicopper(II)-paddlewheel-based metal–organic frameworks (PCN-81 and -82) have been synthesized by using tetratopic ligands featuring 90°-carbazole–dicarboxylate moieties. Both adopt 12-connected tfb topology with nanoscopic octahedra as building units. The freeze-dried PCN-82 shows Brunauer–Emmett–Teller (BET) and Langmuir surface areas as high as 4488 and 4859 m2 g−1, respectively. It also exhibits high H2-adsorption capacity at low pressure (300 cm3 g−1 or 2.6 wt% at 77 K and 1 bar), which can be attributed to its high surface area, microporosity, and open metal sites.

A new semi-rigid 5-(bis(4-carboxybenzyl)amino)isophthalic acid (H4L) is designed and synthesized to obtain novel flexible metal organic frameworks (MOFs). The tetracarboxylate ligand (L4−) links to Cu(II) paddle-wheel second build units (SBUs) under different solvent condition to afford two MOFs, [Cu2(L)(S)2]n (S = DMF, 1 and H2O, 2). Single crystal X-ray diffraction structural analyses reveal that the coordinating solvent molecules are DMF and H2O in the SBUs for 1 and 2, respectively. The torsion angle between two methylene benzoate ring subunits of the ligand is 122.7° in 1 but 175.1° in 2. Three phenyl rings of the ligand are nonplanar and orient in different directions in 1 and 2. A reversible crystal to crystal transformation between 1 and 2 are investigated by exchanging the terminal ligated solvent molecule, in which the phenyl rings of the benzoate subunit act as “a pair of waving wings” accompanying the ligated solvent exchange. Time-dependent powder X-ray diffraction data confirms this reversible dynamic transformation. This hinge within the semi-rigid ligand is a built-in breathing mechanism and suggests a novel approach for general synthesis of breathing MOFs. A gas sorption study for 1 demonstrates 1 has the ability to selectively adsorb CO2 over CH4, H2 and N2.

Three porous (3,24)-connected rht-type metal–organic frameworks (MOFs), [Cu3L(H2O)3]·xsolvents (H6LOH = 4,4′,4″-(hydroxysilanetriyl)tris(triphenyl-3,5-dicarboxylic acid), SDU–6; H6LMe = 4,4′,4″-(methylsilanetriyl)tris(triphenyl-3,5-dicarboxylic acid), SDU–7; H6LiBu = 4,4′,4″-(isobutylsilanetriyl)tris(triphenyl-3,5-dicarboxylic acid), SDU–8), have been successfully prepared from [Cu2(COO)4] paddlewheel SBUs (secondary building units) and C3-symmetric Si-based hexatopic carboxylatelinkers. All porous MOFs are constructed from 3D packing of nanosized cuboctahedral, truncated tetrahedral, and truncated octahedral cages. SDU–6–8 differ only in the functionality of the central Si atom of the hexacarboxylate ligands with hydroxyl, methyl, and isobutyl groups, respectively. Gas adsorption measurements of activated MOFs suggested that decoration of the cage walls with strong polar groups can enhance the adsorption capacities for N2, H2, and CH4. SDU–6 with −OH as the functional group possesses high CH4 uptake (172 cm3 cm–3 at 35 bar), which is very close to DOE target of 180 cm3 cm–3.

Two isostructural lanthanide complexes, [Ln2(INO)4(NO3)2]n·2nDMF [Ln = Eu (1), Tb (2)] (INO = isonicotinate-N-oxide; DMF = N,N-dimethylformamide), have been synthesized under the solvothermal condition and characterized by single-crystal X-ray diffraction, X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and elemental analysis (EA). In these two complexes, each dinuclear Ln(III) unit is connected with six neighboring dinuclear units, which finally constructs a three-dimensional (3D) framework. Along the crystallographic [0 0 1] direction, there are one-dimensional (1D) tunnels, in which free DMF molecules reside as guests. Additionally, the photoluminescent properties of 1 and 2 are also discussed.Two isostructural lanthanide(III) complexes both exhibit 3D microporous pcu structures containing di-nuclear lanthanide(III) units, in which free DMF molecules reside as guests. To further investigate the properties of the above complexes, the photoluminescent properties of 1 and 2 are also discussed.Highlights► Two microporous lanthanide(III) complexes both exhibit 3D pcu structures. ► Free DMF molecules reside in 1D tunnels as guests. ► The title complexes emit intensely in the visible region.

Herein, we report the targeted synthesis and solid state assembly of a novel triazine-based [4+6] organic molecular cage. The tetrahedral cage features a large cavity (∼2070 Å3), and after desolvation, the resultant material exhibits a high Brunauer–Emmett–Teller surface area of 1181 m2 g−1 and also features selective adsorption of CO2 over N2.

Two dicopper(II)-paddlewheel-based metal–organic frameworks (PCN-81 and -82) have been synthesized by using tetratopic ligands featuring 90°-carbazole–dicarboxylate moieties. Both adopt 12-connected tfb topology with nanoscopic octahedra as building units. The freeze-dried PCN-82 shows Brunauer–Emmett–Teller (BET) and Langmuir surface areas as high as 4488 and 4859 m2 g−1, respectively. It also exhibits high H2-adsorption capacity at low pressure (300 cm3 g−1 or 2.6 wt% at 77 K and 1 bar), which can be attributed to its high surface area, microporosity, and open metal sites.

A series of porous hyper-cross-linked polymers with excellent physiochemical stability have been designed and prepared facilely through template-free Friedel–Crafts alkylation reactions between benzene/biphenyl/1,3,5-triphenylbenzene as co-condensing rigid aromatic building blocks and 1,3,5-tris(bromomethyl)benzene or 1,3,5-tris(bromomethyl)-2,4,6-trimethylbenzene as cross-linkers under the catalysis of anhydrous AlCl3 or FeCl3. The systematic study of gas uptake ability shows that anhydrous AlCl3 is a much more effective catalyst than anhydrous FeCl3. The synthesized polymers are thermally stable and are predominantly microporous with high surface areas up to 1783 m2 g−1. In addition, they exhibit high H2 and CO2 uptake capacity/selectivity. Among these materials, C1M3-Al has the highest H2 uptake capacity at 77 K and 1 bar (19.1 mg g−1) and CO2 uptake capacity at 273 K and 1 bar (181 mg g−1); the best CO2/N2 (15/85) selectivity calculated by IAST at 273 K and 1 bar belongs to C1M2-Al (32.3). Moreover, the synthesis route exhibits cost-effective advantages, which are essential for scale-up preparation, thus showing great potential for clean energy applications.

The sharply rising level of atmospheric carbon dioxide resulting from anthropogenic emissions is one of the greatest environmental concerns nowadays. Capture and storage of carbon dioxide (CCS) from coal- or gas-burning power plants is an attractive route to reducing carbon dioxide emissions into the atmosphere. Porous organic polymers (POPs) have been recognized as a very promising candidate for carbon dioxide capture due to their low density, high thermal and chemical stability, large surface area, tunable pore size and structure, and facilely tailored functionality. In this review, we aim to highlight the POPs for CO2 capture and summarize the factors influencing CO2 capture capacity, such as surface area and pore structure, swellable polymers, heteroatomic skeleton and surface functionalized porous organic polymers.

Following the HSAB principle, the cooperative assembly of tetrahedral [Cu4I4(Ina)4]4− metalloligands and 8-connecting [Zr6(μ3-OH)8(OH)8]8+ building units leads to the first heterometallic cluster-based Zr-MOF (1). The results provide a successful strategy for rational design of heterometallic cluster-based Zr-MOFs.