Two Structurally Similar Co5 Cluster-Based Metal-Organic Frameworks Containing Open Metal Sites for Efficient C2H2/CO2 Separation

To reasonably design and synthesize metal-organic frameworks (MOFs) with high stability and excellent adsorption/separation performance, the pore configuration and functional sites are very important. Here, we report two structurally similar cluster-based MOFs using a pyridine-modified low-symmetry ligand [H₄L = 2,6-bis(2',5'-dicarboxyphenyl)pyridine], [(NH₂Me₂)₂][Co₅(L)₂(OCH₃)₂(μ₃-OH)₂·2DMF]·2DMF·2H₂O (1) and [Co₅(L)₂(μ₃-OH)₂(H₂O)₂]·2H₂O·4DMF (2). The structures of 1 and 2 are built from Co₅ clusters, which have one-dimensional open channels, but their microporous environments are different due to the different ways in which ligands bind to the metals. Both MOFs have extremely high chemical stabilities over a wide pH range (2-12). The two MOFs have similar adsorption capacities of C₂H₂ (144.0 cm³ g^-1 for 1 and 141.3 cm³ g^-1 for 2), but 1 has a higher C₂H₂/CO₂ selectivity of 3.5 under ambient conditions. The difference in gas adsorption and separation between the two MOFs has been compared by a breakthrough experiment and theoretical calculation, and the influence of the microporous environment on the gas adsorption and separation performance of MOFs has been further studied.

g-C3N4@Ce-MOF Z-scheme heterojunction photocatalyzed cascade aerobic oxidative functionalization of styrene

A unique composite of the cerium-based metal–organic framework (Ce-UiO-66) modified with graphitic carbon nitride nanosheets (g-C₃N₄) has been synthesized. The g-C₃N₄@Ce-MOF as a photocatalyst was employed in photocatalytic aerobic oxidative Hantzsch pyridine synthesis of styrene.

Tuning the Pore Surface of an Ultramicroporous Framework for Enhanced Methane and Acetylene Purification Performance

Both methane (CH₄) and acetylene (C₂H₂) are important energy source and raw chemicals in many industrial processes. The development of an energy-efficient and environmentally friendly separation and purification strategy for CH₄ and C₂H₂ is necessary. Ultramicroporous metal-organic framework (MOF) materials have shown great success in the separation and purification of small-molecule gases. Herein, the synergy effect of tritopic polytetrazolate and ditopic terephthalate ligands successfully generates a series of isoreticular ultramicroporous cadmium tetrazolate-carboxylate MOF materials (SNNU-13-16) with excellent CH₄ and C₂H₂ purification performance. Except for the uncoordinated tetrazolate N atoms serving as Lewis base sites, the pore size and pore surface of MOFs are systematically engineered by regulating dicarboxylic acid ligands varying from OH-BDC (SNNU-13) to Br-BDC (SNNU-14) to NH₂-BDC (SNNU-15) to 1,4-NDC (SNNU-16). Benefiting from the ultramicroporous character (3.8-5.9 Å), rich Lewis base N sites, and tunable pore environments, all of these ultramicroporous MOFs exhibit a prominent separation capacity for carbon dioxide (CO₂) or C2 hydrocarbons from CH₄ and C₂H₂. Remarkably, SNNU-16 built by 1,4-NDC shows the highest ideal adsorbed solution theory CO₂/CH₄, ethylene (C₂H₄)/CH₄, and C₂H₂/CH₄ separation selectivity values, which are higher than those of most famous MOFs with or without open metal sites. Dynamic breakthrough experiments show that SNNU-16 can also efficiently separate the C₂H₂/CO₂ mixtures with a gas flow rate of 4 mL min^-1 under 1 bar and 298 K. The breakthrough time (18 min g^-1) surpasses most best-gas-separation MOFs and nearly all other metal azolate-carboxylate MOF materials under the same conditions. The above prominently CH₄ and C₂H₂ purification abilities of SNNU-13-16 materials were further confirmed by the Grand Canonical Monte Carlo (GCMC) simulations.

Structural diversity, gas adsorption and magnetic properties of three coordination polymers based on a rigid multicarboxylate ligand

A pictogram: the gas adsorption and magnetic properties of three Co(ii) coordination polymers constructed from 3,5-di(2′,5′-dicarboxylphenyl)benzoic acid ligand have been explored.

Enhanced Z-scheme photocatalytic activity of a π-conjugated heterojunction: MIL-53(Fe)/Ag/g-C3N4

We study the Z-Scheme charge transfer in an MACN heterojunction, looking in particular at the charge transfer between nanosheets and nanorods at the molecular level.

Ag-NPs embedded in two novel Zn3/Zn5-cluster-based metal–organic frameworks for catalytic reduction of 2/3/4-nitrophenol

Two novel microporous Zn-MOFs consist of different SBUs have been used to embed Ag NPs, resulting in two composite catalysts, which show outstanding catalytic activities toward the reduction of nitrophenol.

Preparation of a Fe2O3/MIL-53(Fe) composite by partial thermal decomposition of MIL-53(Fe) nanorods and their photocatalytic activity

A Fe₂O₃/MIL-53(Fe) composite (89% MIL-53(Fe), 11% Fe₂O₃) and Fe₂O₃ were prepared by partial and complete thermal decomposition of MIL-53(Fe).

Sensitive and accurate determination of sialic acids in serum with the aid of dispersive solid-phase extraction using the zirconium-based MOF of UiO-66-NH2 as sorbent

An zirconium-based MOFs of UiO-66-NH₂ has been synthetized and characterized in a dispersive solid-phase extraction procedure combined with HPLC with fluorescence detection for the pre-concentration and detection of sialic acids in serum samples.

Surface functionalization of dinuclear clathrochelates via Pd-catalyzed cross-coupling reactions: facile synthesis of polypyridyl metalloligands

Clathrochelates can be decorated with pyridyl groups by cross-coupling reactions. They represent interesting ligands for supramolecular chemistry and materials science.

An amino-decorated NbO-type metal–organic framework for high C2H2 storage and selective CO2 capture

A novel amino-decorated NbO-type metal–organic framework (ZJU-8) has been designed and synthesized, exhibiting high acetylene storage and selective CO₂ capture and separation capacities at room temperature.

Photocatalytic degradation of methylene blue in ZIF-8

ZIF-8 was used to perform photocatalytic degradation of methylene blue, a typical organic dye.