Crystal Engineering of an nbo Topology Metal-Organic Framework for Chemical Fixation of CO2under Ambient Conditions

Isomorphic MOFs functionalized by free-standing acylamide and organic groups serving as self-supported catalysts for the CO2 cycloaddition reaction

MOFs exhibited different catalytic activities depending on the organic groups decorated on the pore walls, which displayed a synergetic catalytic effect.

A robust indium–porphyrin framework for CO2 capture and chemical transformation

A robust indium–porphyrin framework based on amido-decorated porphyrin ligands is used for CO₂ capture and chemical fixation, showing good catalytic activity and recyclability.

Two microporous metal–organic frameworks constructed from trinuclear cobalt(ii) and cadmium(ii) cluster subunits

This work presents two novel microporous metal–organic frameworks which are constructed from a tetracarboxylate ligand and trinuclear cobalt(ii) and cadmium(ii) cluster subunits.

Experimental and theoretical insights into binary Zn-SBA-15/KI catalysts for the selective coupling of CO2and epoxides into cyclic carbonates under mild conditions

Experimental and theoretical evidence gives insights into Zn-SBA-15/KI for selective coupling of CO₂and epoxides under mild conditions.

The electrochemical properties, nitrogen adsorption, and photocatalytic activities of three 3D metal–organic frameworks bearing the rigid terphenyl tetracarboxylates ligands

Three new 3D complexes derived from the rigid terphenyl tetracarboxylates ligands with different transition metal ions have been successfully prepared. In addition, the title complexes exhibit different properties.

Exceptional gravimetric and volumetric CO2 uptake in a palladated NbO-type MOF utilizing cooperative acidic and basic, metal–CO2 interactions

A novel NbO-type MOF based on a palladated organic linker shows exceptional gravimetric and volumetric CO₂ uptake.

POSS-based meso-/macroporous covalent networks: supporting and stabilizing Pd for Suzuki–Miyaura reaction at room temperature

Porous covalent organic networks synthesized by Schiff base chemistry reaction of POSS and terephthalic aldehyde could serve as both supports and stabilizers for Pd catalyst, which exhibited excellent performances for Suzuki-Miyaura reactions.

A microporous Cu-MOF with optimized open metal sites and pore spaces for high gas storage and active chemical fixation of CO2

A novel Cu-MOF featuring optimized open metal sites and pore spaces displays excellent performance in terms of gas storage and heterogeneous catalysis activity.

One-step assembly of a hierarchically porous phenolic resin-type polymer with high stability for CO2 capture and conversion

A hierarchically porous phenolic resin-type polymer with high stability has been rationally synthesized, which behaves as an excellent adsorbent and catalyst for CO₂ capture and conversion.

Amino-functionalized metal–organic framework for adsorption and separation of dichloromethane and trichloromethane

MOF functionalized with –NH₂ exhibits improved adsorption capacity and selectivity for the adsorption and separation of dichloromethane and trichloromethane.

Construction of solvent-dependent self-assembled porous Ni(ii)-coordinated frameworks as effective catalysts for chemical transformation of CO2

Two types of Ni(ii)-based coordinated frameworks have been solvothermally synthesized via solvent driven self-assembly, showing efficient heterogeneous catalytic activity toward cycloaddition of CO₂ with epoxides under ambient conditions.

Polyoxometalate-based homochiral metal-organic frameworks for tandem asymmetric transformation of cyclic carbonates from olefins

Currently, great interest is focused on developing auto-tandem catalytic reactions; a substrate is catalytically transferred through mechanistically distinct reactions without altering any reaction conditions. Here by incorporating a pyrrolidine moiety as a chiral organocatalyst and a polyoxometalate as an oxidation catalyst, a powerful approach is devised to achieve a tandem catalyst for the efficient conversion of CO₂ into value-added enantiomerically pure cyclic carbonates. The multi-catalytic sites are orderly distributed and spatially matched in the framework. The captured CO₂ molecules are synergistically fixed and activated by well-positioned pyrrolidine and amine groups, providing further compatibility with the terminal W=O activated epoxidation intermediate and driving the tandem catalytic process in a single workup stage and an asymmetric fashion. The structural simplicity of the building blocks and the use of inexpensive and readily available chemical reagents render this approach highly promising for the development of practical homochiral materials for CO₂ conversion.

Using a single catalyst to promote multiple distinct reactions without alteration in reaction conditions is an attractive synthetic goal. Here, to this end, the authors have developed a polyoxometalate-based metal-organic framework for the synthesis of cyclic carbonates from olefins.

Design of Zeolitic Imidazolate Framework Derived Nitrogen-Doped Nanoporous Carbons Containing Metal Species for Carbon Dioxide Fixation Reactions

Various N-doped nanoporous carbons containing metal species were prepared by direct thermal conversion of zeolitic imidazolate frameworks (ZIFs; ZIF-7, -8, -9, and -67) at different temperatures (600, 800, and 1000 °C). These materials were utilized as bifunctional acid-base catalysts to promote the reaction of CO2 with epoxides to form cyclic carbonates under 0.6 MPa of CO2 at 80 °C. The catalyst generated by thermal conversion of ZIF-9 at 600 °C (C600-ZIF-9) was found to exhibit a higher catalytic activity than the other ZIFs, other conventional catalysts, and other metal-organic framework catalysts. The results of various characterization techniques including elemental analysis, X-ray diffraction, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and transmission electron microscopy show that C600-ZIF-9 contains partly oxidized Co nanoparticles and N species. Temperature-programmed desorption measurements by using CO2 and NH3 as probe molecules revealed that C600-ZIF-9 has both Lewis acid and Lewis base catalytic sites. Finally, the substrate scope was extended to seven other kinds of epoxides.

Chemical principles underpinning the performance of the metal-organic framework HKUST-1

A common feature of multi-functional metal-organic frameworks is a metal dimer in the form of a paddlewheel, as found in the structure of Cu3(btc)2 (HKUST-1). The HKUST-1 framework demonstrates exceptional gas storage, sensing and separation, catalytic activity and, in recent studies, unprecedented ionic and electrical conductivity. These results are a promising step towards the real-world application of metal-organic materials. In this perspective, we discuss progress in the understanding of the electronic, magnetic and physical properties of HKUST-1, representative of the larger family of Cu···Cu containing metal-organic frameworks. We highlight the chemical interactions that give rise to its favourable properties, and which make this material well suited to a range of technological applications. From this analysis, we postulate key design principles for tailoring novel high-performance hybrid frameworks.

Highly Efficient Heterogeneous Hydroformylation over Rh-Metalated Porous Organic Polymers: Synergistic Effect of High Ligand Concentration and Flexible Framework

A series of diphosphine ligand constructed porous polymers with stable and flexible frameworks have been successfully synthesized under the solvothermal conditions from polymerizing the corresponding vinyl-functionalized diphosphine monomers. These insoluble porous polymers can be swollen by a wide range of organic solvents, showing similar behavior to those of soluble analogues. Rather than just as immobilizing homogeneous catalysts, these porous polymers supported with Rh species demonstrate even better catalytic performance in the hydroformylations than the analogue homogeneous catalysts. The sample extraordinary performance could be attributed to the combination of high ligand concentration and flexible framework of the porous polymers. Meanwhile, they can be easily separated and recycled from the reaction systems without losing any activity and selectivity. This excellent catalytic performance and easy recycling heterogeneous catalyst property make them be very attractive. These diphosphine ligand constructed porous polymers may provide new platforms for the hydroformylation of olefins in the future.

Crystalline capsules: metal-organic frameworks locked by size-matching ligand bolts

Metal-organic frameworks (MOFs) are shown to be good examples of a new class of crystalline porous materials for guest encapsulation. Since the encapsulation/release of guest molecules in MOF hosts is a reversible process in nature, how to prevent the leaching of guests from the open pores with minimal and nondestructive modifications of the structure is a critical issue. To address this issue, we herein propose a novel strategy of encapsulating guests by introducing size-matching organic ligands as bolts to lock the pores of the MOFs through deliberately anchoring onto the open metal sites in the pores. Our proposed strategy provides a mechanical way to prevent the leaching of guests and thereby has less dependence on the specific chemical environment of the hosts, thus making it applicable for a wide variety of existing MOFs once the size-matching ligands are employed.

Absorbate-induced piezochromism in a porous molecular crystal

Atmospherically stable porous frameworks and materials are interesting for heterogeneous solid-gas applications. One motivation is the direct and selective uptake of pollutant/hazardous gases, where the material produces a measurable response in the presence of the analyte. In this report, we present a combined experimental and theoretical rationalization for the piezochromic response of a robust and porous molecular crystal built from an extensively fluorinated trispyrazole. The electronic response of the material is directly determined by analyte uptake, which provokes a subtle lattice contraction and an observable bathochromic shift in the optical absorption onset. Selectivity for fluorinated absorbates is demonstrated, and toluene is also found to crystallize within the pore. Furthermore, we demonstrate the application of electronic structure calculations to predict a physicochemical response, providing the foundations for the design of electronically tunable porous solids with the chemical properties required for development of novel gas-uptake media.

Polar group and defect engineering in a metal-organic framework: synergistic promotion of carbon dioxide sorption and conversion

A sulfone-functionalized metal-organic framework (MOF), USTC-253, has been synthesized that exhibits a much higher CO2 uptake capacity (168-182 %) than the corresponding unfurnished MOFs. The introduction of trifluoroacetic acid (TFA) during the synthesis of USTC-253 affords defect-containing USTC-253-TFA with exposed metal centers, which has an increased CO2 uptake (167 %) compared to pristine USTC-253. USTC-253-TFA exhibits a very high ideal adsorption solution theory selectivity (S=75) to CO2 over N2 at 298 K. In addition, USTC-253-TFA demonstrates good catalytic activity and recyclability in the cycloaddition of CO2 and epoxide at room temperature under 1 bar CO2 pressure as a result of the presence of Lewis and Brønsted acid sites, which were evaluated by diffuse reflectance infrared Fourier transform spectroscopy with a CO probe molecule. We propose that the CO2 adsorption capability has a positive correlation with the catalytic performance toward CO2 conversion.

Porous coordination polymers with ubiquitous and biocompatible metals and a neutral bridging ligand

The design of inexpensive and less toxic porous coordination polymers (PCPs) that show selective adsorption or high adsorption capacity is a critical issue in research on applicable porous materials. Although use of Group II magnesium(II) and calcium(II) ions as building blocks could provide cheaper materials and lead to enhanced biocompatibility, examples of magnesium(II) and calcium(II) PCPs are extremely limited compared with commonly used transition metal ones, because neutral bridging ligands have not been available for magnesium(II) and calcium(II) ions. Here we report a rationally designed neutral and charge-polarized bridging ligand as a new partner for magnesium(II) and calcium(II) ions. The three-dimensional magnesium(II) and calcium(II) PCPs synthesized using such a neutral ligand are stable and show selective adsorption and separation of carbon dioxide over methane at ambient temperature. This synthetic approach allows the structural diversification of Group II magnesium(II) and calcium(II) PCPs.

Inexpensive porous materials synthesized from Group II metals may be useful for industrial applications. Here, the authors demonstrate that neutral bridging ligands can be used for the synthesis of magnesium(II) and calcium(II) porous coordination polymers.

Luminescent MOF material based on cadmium(ii) and mixed ligands: application for sensing volatile organic solvent molecules

A luminescent MOF was constructed by employing a mixed ligands strategy and may be used as a potential luminescent probe for the detection of acetone.

Investigation of prototypal MOFs consisting of polyhedral cages with accessible Lewis-acid sites for quinoline synthesis

A series of prototypal metal–organic frameworks (MOFs) consisting of polyhedral cages with accessible Lewis-acid sites, have been systematically investigated for Friedländer annulation reaction.

Gas promotes the crystallization of nano-sized metal–organic frameworks in ionic liquid

Gas can promote metal–organic framework (MOF) crystallization and MOF nanoparticles were obtained at room temperature.

Toward a robust porous coordination polymer: the inhibition of mutual movement between interpenetrating sub-networks by introduction of multiple C–H⋯π interactions

We demonstrate that a robust porous coordination polymer can be achieved by introduction of multiple C–H⋯π interactions between diamonded sub-networks.

Open metal sites dangled on cobalt trigonal prismatic clusters within porous MOF for CO2 capture

A porous MOF adapting a rare SBU with open metal sites dangled on cobalt trigonal prismatic clusters has been constructed based upon a custom-designed octacarboxylate ligand.

Synthesis of metal–organic framework particles and thin films via nanoscopic metal oxide precursors

Metal–organic framework films were fabricated on versatile substrates through the nanoscale-facilitated transformation of nanoscopic metal-oxide precursors.

A metal–organic framework as a highly efficient and reusable catalyst for the solvent-free 1,3-dipolar cycloaddition of organic azides to alkynes

A new highly efficient and reusable Cu-MOF has been developed for the regioselective synthesis of 1,2,3-triazoles via the 1,3-dipolar cycloaddition of organic azides to terminal alkynes under solvent-free conditions.

4-(4-Carboxyphenoxy)phthalate-based coordination polymers and their application in sensing nitrobenzene

Structural characterization of 4-(4-carboxyphenoxy)phthalate-based Cd²⁺ and Mn²⁺ coordination polymers are reported, and Cd²⁺ coordination polymer can serve as probe to sense nitrobenzene.

A highly robust metal–organic framework based on an aromatic 12-carboxyl ligand with highly selective adsorption of CO2 over CH4

A stable microporous anionic MOF based on a dendritic aromatic 12-carboxyl ligand was synthesized, which demonstrates high Q_st for CO₂ and highly selective gas adsorption of CO₂ over CH₄.

Melamine–ZnI2 as heterogeneous catalysts for efficient chemical fixation of carbon dioxide to cyclic carbonates

Melamine–ZnI₂ as heterogeneous catalysts showed high activity and versatility for cycloaddition of CO₂ to epoxides due to the synergistic effects.