Reticular Synthesis of 3D Metal Cluster-Based COFs With Record High-Connectivity for Efficient Photocatalytic HO Synthesis.

The assembly of metal clusters with organic building units by covalent bonds to form metal cluster-based covalent-organic frameworks (MCCOFs) material is a novel strategy in reticular synthesis. However, only 2, 3, and 6 connectivity of MCCOFs have been achieved in reported structures. Developing a higher connectivity remains a great challenge in the MCCOFs due to the difficulties in introducing multiple connecting nodes to the metal cluster.

Modulating Adsorption Kinetics in a 3D-Interconnected Nanocavity Framework with Narrow Apertures for Enhanced Propylene Separation.

The energy-intensive distillation currently used for CH/CH separation─challenged by their small boiling point difference─could be improved via adsorption. However, most porous materials face a trade-off among CH adsorption capacity, selectivity, and kinetics. Herein, we report the synthesis and characterization of a novel metal-organic framework, denoted NiPzBim, constructed from a weak Lewis-base pyrazole-based ligand PzBim and the weak Lewis-acid Ni, featuring 3D pore structures with nanocavities (∼1 nm) connected by very narrow apertures (∼5 Å).

Charge-Transport Divergence in Ultrastable Heterometal-Oxo Clusters Exerting Significant Effect on Photoreactivity.

The transfer path of photogenerated charges greatly affects the final photocatalytic performance, but this important fact has not been clearly demonstrated experimentally. Here, we construct an ultrastable crystalline catalytic system including three heterometal-oxo clusters, BiM-TBC4A (M = group IVB metal-Ti/Zr/Hf), which include cubic metal-oxo cluster core with eight Bi atoms at the vertices, one M atom at the body center, and six M atoms above the cubic face centers. It is worth noted that the change of group IVB elements in BiM-TBC4A can specifically modulate the LUMO-HOMO orbitals to distribute on different active metal atoms.

A Stable Polyoxovanadate-based Metal-organic Framework Containing Dual Catalytic Sites for Efficient Synthesis of p-benzoquinones.

A novel polyoxovanadate-based metal-organic framework (POV-MOF), [Cu(bix)]{VO} (V-Cu-MOF, bix=1,4-bis(imidazol-1-ylmethyl)benzene), has been successfully synthesized and characterized. The V-Cu-MOF demonstrates exceptional performance in the selective oxidation of 2,3,6-trimethylphenol to 2,3,5-trimethyl-1,4-benzoquinone within just 10 minutes under mild conditions using hydrogen peroxide as the oxidant. The V-Cu-MOF exhibits remarkable versatility, efficiently oxidizing various substituted phenols while maintaining high catalytic activity.

Conjugated phthalocyanine-based framework as artificial SEI for over 400 Wh kg lithium-metal battery.

High-voltage lithium-metal batteries (HVLMBs) are appealing candidates for next-generation high-energy rechargeable batteries, but their practical applications are still limited by the severe capacity degradation, attributed to the poor interfacial stability and compatibility between the electrode and the electrolyte. In this work, a 2D conjugated phthalocyanine framework (CPF) containing single atoms (SAs) of cobalt (CoSAs-CPF) is developed as a novel artificial solid-electrolyte interphase (SEI) in which a large amount of charge is transferred to the CPF skeleton due to the Lewis acid activity of the Co metal sites and the strong electron-absorbing property of the cyano group (-CN), greatly enhancing the adsorption of the Li and regulating the Li distribution toward dendrite-free LMBs, which are superior to most of the reported SEI membranes. As a result, the Li||Li symmetrical cell with CoSAs-CPF-modified Li anodes (CoSAs-CPF@Li) exhibits a low polarization with an area capacity of 1.

3D Covalent Organic Frameworks with 16-Connectivity for Photocatalytic C(sp)-C(sp) Cross-Coupling.

The connectivity (valency) of building blocks for constructing 3D covalent organic frameworks (COFs) has long been limited to 4, 6, 8, and 12. Developing a higher connectivity remains a great challenge in the field of COF structural design. Herein, this work reports a hierarchical expansion strategy for making 16-connected building blocks to construct 3D COFs with sqc topology.

In situ Construction of Single-Atom Electronic Bridge on COF to Enhance Photocatalytic H Production.

Photocatalytic hydrogen production is one of the most valuable technologies in the future energy system. Here, we designed a metal-covalent organic frameworks (MCOFs) with both small-sized metal clusters and nitrogen-rich ligands, named COF-CuTG. Based on our design, small-sized metal clusters were selected to increase the density of active sites and shorten the distance of electron transport to active sites.

Insight into the Mechanism of CO Chemical Fixation into Epoxides by Windmill-Shaped Polyoxovanadate and -BuNX (X = Br, I).

Carbon dioxide (CO) coupled with epoxide to generate cyclic carbonate stands out in carbon neutrality due to its 100% atom utilization. In this work, the mechanism of CO cycloaddition with propylene oxide (PO) cocatalyzed by windmill-shaped polyoxovanadate, [(CNH)(CHO)VVO]·4CHOH (V-1), and -BuNX (X = Br, I) was thoroughly investigated using density functional theory (DFT) calculations. The ring-opening, CO-insertion, and ring-closing steps of the process were extensively studied.

Photochromic radical states in 3D covalent organic frameworks with zyg topology for enhanced photocatalysis.

Covalent-organic frameworks (COFs) with photoinduced donor-acceptor (D-A) radical pairs show enhanced photocatalytic activity in principle. However, achieving long-lived charge separation in COFs proves challenging due to the rapid charge recombination. Here, we develop a novel strategy by combining [6 + 4] nodes to construct -type 3D COFs, first reported in COF chemistry.

Bridging the Homogeneous and Heterogeneous Catalysis by Supramolecular Metal-Organic Cages with Varied Packing Modes.

Integrating the advantages of homogeneous and heterogeneous catalysis has proved to be an optimal strategy for developing catalytic systems with high efficiency, selectivity, and recoverability. Supramolecular metal-organic cages (MOCs), assembled by the coordination of metal ions with organic linkers into discrete molecules, have performed solvent processability due to their tunable packing modes, endowing them with the potential to act as homogeneous or heterogeneous catalysts in different solvent systems. Here, the design and synthesis of a series of stable {Cu} cluster-based tetrahedral MOCs with varied packing structures are reported.

Photocatalytic aerobic oxidation of C(sp)-H bonds.

In modern industries, the aerobic oxidation of C(sp)-H bonds to achieve the value-added conversion of hydrocarbons requires high temperatures and pressures, which significantly increases energy consumption and capital investment. The development of a light-driven strategy, even under natural sunlight and ambient air, is therefore of great significance. Here we develop a series of hetero-motif molecular junction photocatalysts containing two bifunctional motifs.

Calix[4]arene-Functionalized Titanium-Oxo Compounds for Perceiving Differences in Catalytic Reactivity Between Mono- and Multimetallic Sites.

While the difference in catalytic reactivity between mono- and multimetallic sites is often attributed to more than just the number of active sites, still few catalyst model systems have been developed to explore more underlying causal factors. In this work, we have elaborately designed and constructed three stable calix[4]arene (C4A)-functionalized titanium-oxo compounds, , , and , with well-defined crystal structures, increasing nuclearity, and tunable light absorption capacity and energy levels. Among them, and can be taken as model catalysts to compare the differences in reactivity between mono- and multimetallic sites.

Molecular oxidation-reduction junctions for artificial photosynthetic overall reaction.

Constructing redox semiconductor heterojunction photocatalysts is the most effective and important means to complete the artificial photosynthetic overall reaction (i.e., coupling CO photoreduction and water photo-oxidation reactions).

Superiority of Iridium Photocatalyst and Role of Quinuclidine in Selective α-C(sp)-H Alkylation: Theoretical Insights.

Recent experimental work reported that visible-light photoredox catalysis coupled with primary sulfonamides and electron-deficient alkenes could efficiently construct C-C bonds at the α-position of primary amine derivatives under mild conditions. Here, a systematic study was conducted to explore the non-negligible excited-state single-electron-transfer (SET) processes and the catalytic cycle. Hydrogen atom transfer (HAT) catalysis containing different site-selective functionalization, involved as a critical process during the reaction, was computationally characterized.

Different Protonic Species Affecting Proton Conductivity in Hollow Spherelike Polyoxometalates.

Polyoxometalates (POMs), which possess strong acidity and chemical stability, are promising solid proton conductors and potential candidates for proton exchange membrane fuel cell applications. To investigate how factors such as proton concentration and carrier affect the overall proton conduction, we have synthesized new compounds HImMo (Im, imidazole), HMeImMo, ILMo, and TBAMo with hollow structures and HImPMo with a solid spherelike structure. These crystal models were prepared by encapsulating POM with organic molecules with different proton contents.

Orthogonal reactivity of Ni(i)/Pd(0) dual catalysts for Ullmann C-C cross-coupling: theoretical insight.

Dual catalysis has become a desirable alternative because of the synergetic effect of two distinct catalysts, but little is known about the mechanism of dual catalysis and its effect on the high reactivity and selectivity. Here, a novel Ullmann C-C cross-coupling of bromobenzene and 4-methoxyphenyltriflate via nickel/palladium dual catalysis has been investigated using density functional theory. The orthogonal reactivity of NiI/Pd0 combination is the precondition and foundation of achieving such a Ullmann cross-coupling reaction.

[Perioperative management of severe obstructive sleep apnea hypopnea syndrome].

Objective: To investigate the perioperative management of severe obstructive sleep apnea hypopnea syndrome (OSAHS).

Methods: Fifty-three patients with severe OSAHS received uvulopalatopharyngoplasty with uvula preservation and radiofrequency tongue base reduction. All the patients were treated with automated continuous positive airway pressure (CPAP) for 3-7 days before operation and automated antibiotic therapy administered in the oropharynx, with 24 h ECG monitoring postoperatively.

[Modified type I thyroplasty for treating unilateral vocal cord paralysis].

Objective: To explore a new surgical approach for treating unilateral vocal cord paralysis.

Methods: Five cases of unilateral vocal cord paralysis due to various causes were treated with modified type I thyroplasty. Laryngostroboscopy and electroglottography were performed before and after the operations.