Eco-Friendly Sustainable and Responsive High-Performance Benzotriazole-Metal Organic Frameworks/Silica Composite Coating with Active/Passive Corrosion Protection on Copper

Coatings with only passive protection cannot offer long-term anticorrosion on metals. Eco-friendly sustainable and responsive coating for active/passive corrosion protection is desirable to extend the service life of metals. Here, benzotriazole (BTA)-metal organic frameworks (Cu-MOFs, UiO-66) were embedded in silica (SiO2) coating by one-step electrodeposition on copper. Combined with passive capability of MOFs and active protection of BTA inhibitor, the composite coating (BTA-MOF/SiO2) exhibited high and stable corrosion resistance, confirmed by microstructure characterizations and electrochemical tests. As a result, the as-prepared composite coating exhibited superhydrophobicity with a water contact angle of 154.2°. With loading of BTA-MOF in SiO2 coating, the impedance modulus at 0.01 Hz increased by ∼10-fold and the corrosion current density decreased to 3.472 × 10-9 A·cm-2. Immersion and salt spray tests confirmed the long-term protection of the composite coating. The responsive release of BTA inhibitor endows the coating with a responsively anticorrosive behavior. The active-passive ability makes the coating a good candidate for protection on metals used in highly salty environments.

Ionic metal-organic frameworks (iMOFs): progress and prospects as ionic functional materials

Metal-organic frameworks (MOFs) have been a research hotspot for the last two decades, witnessing an extraordinary upsurge across various domains in materials chemistry. Ionic MOFs (both anionic and cationic MOFs) have emerged as next-generation ionic functional materials and are an important subclass of MOFs owing to their ability to generate strong electrostatic interactions between their charged framework and guest molecules. Furthermore, the presence of extra-framework counter-ions in their confined nanospaces can serve as additional functionality in these materials, which endows them a significant advantage in specific host-guest interactions and ion-exchange-based applications. In the present review, we summarize the progress and future prospects of iMOFs both in terms of fundamental developments and potential applications. Furthermore, the design principles of ionic MOFs and their state-of-the-art ion exchange performances are discussed in detail and the future perspectives of these promising ionic materials are proposed.

A self-assembly solvothermal synthesis of SiMoVn@[Cu6O(TZI)3(H2O)6]4·nH2O for the efficient selective oxidation of various alkylbenzenes

A series of SiMoVn@rht-MOF-1 were isolated via a one-pot self-assembly solvothermal synthesis, exhibiting effective catalytic activity and excellent recyclability.

Crystal structure of catena-poly[[bis-(acetato-κO)copper(II)]-bis-[μ-4-(1H-imidazol-1-yl)phenol]-κ2N3:O;κ2O:N3]

In the title compound, [Cu(CH3COO)2(C9H8N2O)2] n , the CuII ion resides on a centre of inversion, displaying a tetra-gonally distorted octa-hedral coordination environment defined by two pairs of N and O atoms of symmetry-related 4-(1H-imidazol-1-yl)phenol ligands and the O atoms of two symmetry-related acetate ligands. The bridging mode of the 4-(1H-imidazol-1-yl)phenol ligands is associated with a very long Cu⋯O inter-actions involving the phenol O atom of the heterocyclic ligand, which creates chains extending parallel to [100]. In the crystal, the chains are arranged in a distorted hexa-gonal rod packing and are linked via C-H⋯O hydrogen bonds and by π-π stacking inter-actions involving centrosymmetrically related pairs of imidazole and phenol rings.

Post-synthetic ion-exchange process in nanoporous metal–organic frameworks; an effective way for modulating their structures and properties

In this review paper, we considered all of the reports on the ion-exchange process which occur in the pores of MOFs. A comparison between MOFs before and after-exchange process and their applications were addressed.

Can a highly flexible copper(i) cluster-containing 1D and 2D coordination polymers exhibit MOF-like properties?

The p-TolS(CH₂)₈STol-p and p-tBuC₆H₄S(CH₂)₈SC₆H₄-tBu-p ligands react with CuI respectively in MeCN and EtCN and in EtCN form the 2D and 1D polymers [Cu₈I₈(p-TolS(CH₂)₈STol-p)₃(solvent)₂]_n (solvent = MeCN, EtCN) and [Cu₄I₄(p-tBuC₆H₄S(CH₂)₈SC₆H₄-tBu-p)₂(EtCN)]_n susceptible to exchange solvent molecules.

Fe3O4@SiO2/EDAC–Pd(0) as a novel and efficient inorganic/organic magnetic composite: sustainable catalyst for the benzylic C–H bond oxidation and reductive amination under mild conditions

Magnetically recyclable ethylene diamine functionalized inorganic/organic composite, Fe₃O₄@SiO₂/EDAC–Pd(0) for selective C–H bond oxidation and reductive amination under sustainable reaction media.

A Review on Breathing Behaviors of Metal-Organic-Frameworks (MOFs) for Gas Adsorption

Metal-organic frameworks (MOFs) are a new class of microporous materials that possess framework flexibility, large surface areas, "tailor-made" framework functionalities, and tunable pore sizes. These features empower MOFs superior performances and broader application spectra than those of zeolites and phosphine-based molecular sieves. In parallel with designing new structures and new chemistry of MOFs, the observation of unique breathing behaviors upon adsorption of gases or solvents stimulates their potential applications as host materials in gas storage for renewable energy. This has attracted intense research energy to understand the causes at the atomic level, using in situ X-ray diffraction, calorimetry, Fourier transform infrared spectroscopy, and molecular dynamics simulations. This article is developed in the following order: first to introduce the definition of MOFs and the observation of their framework flexibility. Second, synthesis routes of MOFs are summarized with the emphasis on the hydrothermal synthesis, owing to the environmental-benign and economically availability of water. Third, MOFs exhibiting breathing behaviors are summarized, followed by rationales from thermodynamic viewpoint. Subsequently, effects of various functionalities on breathing behaviors are appraised, including using post-synthetic modification routes. Finally, possible framework spatial requirements of MOFs for yielding breathing behaviors are highlighted as the design strategies for new syntheses.

Applications of metal–organic frameworks in heterogeneous supramolecular catalysis

The contributions of MOFs to the field of heterogeneous supramolecular catalysis are comprehensively reviewed with regard to active sites, selectivity, as well as host–guest chemistry.

Coordination frameworks assembled from CuII ions and H2-1,3-bdpb ligands: X-ray and magneto structural investigations, and catalytic activity in the aerobic oxidation of tetralin

CFA-5, a novel MOF containing Cu(ii) ions and pyrazolate ligands, shows heterogeneous catalytic activity in the liquid-phase aerobic oxidation of tetralin.

The role of C–H⋯π interactions in modulating the breathing amplitude of a 2D square lattice net: alcohol sorption studies

Higher uptake of longer chain alcohol vapours by a flexible 2D Zn-framework1is attributed to C–H⋯π interactions with hydrophobic channel walls.

Pyridinium linkers and mixed anions in cationic metal–organic frameworks

Mixing anions in a cationic metal–organic framework with pyridinium linkers significantly enhances CO₂ selectivity and uptake capacity.

The Chemistry and Applications of Metal-Organic Frameworks

Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.

Two Zn(II) metal-organic frameworks with coordinatively unsaturated metal sites: structures, adsorption, and catalysis

Assembly of Zn(NO(3))(2) with the tripodal ligand H(3)TCPB (1,3,5-tri(4-carboxyphenoxy)benzene) affords two porous isoreticular metal-organic frameworks, [Zn(3)(TCPB)(2)⋅2DEF]⋅3DEF (1) and [Zn(3)(TCPB)(2)⋅2H(2)O]⋅2H(2)O⋅4DMF (2). Single-crystal X-ray diffraction analyses reveal that 1 crystallizes in the monoclinic space group P2(1)/c and possesses a 2D network containing 1D microporous opening channels with an effective size of 3.0×2.9 Å(2), whereas 2 crystallizes in the trigonal space group P3c1 and also possesses a 2D network containing 1D channels, with an effective aperture of 4.0×4.0 Å(2). TOPOS analysis reveals that both 1 and 2 have a (3,6)-connected network topology with the Schläfli symbol of (4(3)⋅6(12)) (4(3))(2). According to the variable-temperature powder X-ray diffraction patterns, the solid phase of 1 can be converted into that of 2 during a temperature-induced dynamic structural transformation, thus indicating that the framework of 2 represents the most thermally stable polymorph. Desolvated 2 exhibits highly selective adsorption behaviors toward H(2)/N(2), CO(2)/N(2), and CO(2)/CH(4); furthermore, it displays size-selective catalytic activity towards carbonyl cyanosilylation and Henry (nitroaldol) reactions.

Two ligand-functionalized Pb(II) metal-organic frameworks: structures and catalytic performances

A microporous Pb(II) metal-organic framework (MOF) [PbL(2)]·2DMF·6H(2)O (1) has been assembled from a N-oxide and amide doubly functionalized ligand HL (= N-(4-carboxyphenyl)isonicotinamide 1-oxide). Complex 1 features a three-dimensional (3D) framework possessing one-dimensional (1D) rhombic channels with dimensions of 13 × 13 Å(2). The 3D framework is built up from 1D PbO(2) chains that link ligands in parallel fashion to construct single-wall channels. When recrystallizing 1 in a DMSO-DMF mixture (3 : 5 v/v), a new coordination polymer, [PbL(2)]·DMF·2H(2)O (2), was obtained. Complex 2 is also a 3D framework containing 1D rectangular channels, but the channel dimensions become reduced in size to 13 × 8 Å(2) due to reorganization of the Pb(ii) coordination environment. The PbO(2) chains in 2 are reformed to link ligands in a double-wall fashion, significantly reducing the channel size. Even though, the guest exchange study indicates that the DMF molecules in 2 could be replaced with benzene molecules when immersing in benzene solvent, showing single-crystal-to-single-crystal (SC-SC) guest exchange in the solid state and leading to a daughter crystal [PbL(2)]·0.5C(6)H(6)·2H(2)O (2'). Desolvated 1 and 2 display preferential adsorption behaviors of water vapour over CO(2) due to the hydrophilic nature of the channels and the strong host-guest interactions. Catalytic tests indicate that desolvated 1 and 2 have size-selective catalytic activity towards the Knoevenagel condensation reaction.