Carlos

On page 4775, J.-S. Chang, C. Serre, and co-workers design and synthesize a new scalable hydrophilic metal–organic framework material built up from a bio-renewable linker named MIL-160, showing outstanding water-sorption properties, as highlighted by a comparison with the benchmark of each family of porous solids envisaged so far for applications in adsorption-driven heat pumps and chillers.

The porphyrin boxes (PB-1 and PB-2), which are rationally designed porous organic cages with a large cavity using well-defined and rigid 3-connected triangular and 4-connected square shaped building units are reported. PB-1 has a cavity as large as 1.95 nm in diameter and shows high chemical stability in a broad pH range (4.8 to 13) in aqueous media. The crystalline nature as well as cavity structure of the shape-persistent organic cage crystals were intact even after complete removal of guest molecules, leading to one of the highest surface areas (1370 m²g⁻¹) among the known porous organic molecular solids. The size of the cavities and windows of the porous organic cages can be modulated using different sized building units while maintaining the topology of the cages, as illustrated with PB-2. Interestingly, PB-2 crystals showed unusual N₂ sorption isotherms as well as high selectivity for CO₂ over N₂ and CH₄ (201 and 47.9, respectively at 273 K at 1 bar).

Find a way: A new strategy for synthesis of shape-persistent organic cages based on porphyrins through rational design is reported. The size of cavities and windows of the organic cages can be modulated using different sized building units while maintaining the topology of the cages.

The rational construction of covalent or noncovalent organic two-dimensional nanosheets is a fascinating target because of their promising applications in electronics, membrane technology, catalysis, sensing, and energy technologies. Herein, a large-area (square millimeters) and free-standing 2D supramolecular polymer (2DSP) single-layer sheet (0.7–0.9 nm in thickness), comprising triphenylene-fused nickel bis(dithiolene) complexes has been readily prepared by using the Langmuir–Blodgett method. Such 2DSPs exhibit excellent electrocatalytic activities for hydrogen generation from water with a Tafel slope of 80.5 mV decade⁻¹ and an overpotential of 333 mV at 10 mA cm⁻², which are superior to that of recently reported carbon nanotube supported molecular catalysts and heteroatom-doped graphene catalysts. This work is promising for the development of novel free-standing organic 2D materials for energy technologies.

Standing up: The Langmuir–Blodgett method can be used to prepare two-dimensional supramolecular polymer (2DSP) sheets from nickel bis(dithiolene) complexes at the air–water interface (see figure). These free-standing single-layer sheets, which are 0.7–0.9 nm thick and square millimeters in area, showed excellent electrocatalytic activities in the hydrogen evolution reaction from water.

Herein, the concept of macrocyclic weakly coordinating anions (M-WCAs) is introduced. Synthetic methodologies are described how to access M-WCAs by thermodynamically controlled self-assembly in high yields, in particular through condensation and alkyne metathesis reactions. The anticipated properties and applications of M-WCAs in solid state and in solution are discussed, specifically for gas storage and separation, homogeneous and heterogeneous catalysis, and as liquid and solid electrolytes.

A flavor of the weak: Macrocyclic weakly coordinating anions, synthesized by thermodynamically controlled self-assembly in high yields, are a fascinating new concept offering many new opportunities for electrolyte systems, catalysis, and gas storage and separation.

The vicinal P/B frustrated Lewis pair (FLP) Mes₂PCH₂CH₂B(C₆F₅)₂ undergoes 1,1-carboboration reactions with the Me₃Si-substituted enynes to give ring-enlarged functionalized C₃-bridged P/B FLPs. These serve as active FLPs in the activation of dihydrogen to give the respective zwitterionic [P]H⁺/[B]H⁻ products. One such product shows activity as a metal-free catalyst for the hydrogenation of enamines or a bulky imine. The ring-enlarged FLPs contain dienylborane functionalities that undergo “bora-Nazarov”-type ring-closing rearrangements upon photolysis. A DFT study had shown that the dienylborane cyclization of such systems itself is endothermic, but a subsequent C₆F₅ migration is very favorable. Furthermore, substituted 2,5-dihydroborole products are derived from cyclization and C₆F₅ migration from the photolysis reaction. In the case of the six-membered annulation product, a subsequent stereoisomerization reaction takes place and the resultant compound undergoes a P/B FLP 1,2-addition reaction with a terminal alkyne with rearrangement.

The vicinal P/B frustrated Lewis pair (FLP) Mes₂PCH₂CH₂B(C₆F₅)₂ undergoes 1,1-carboboration reactions with Me₃Si-substituted enynes to give ring-enlarged functionalized C₃-bridged P/B FLPs. These serve as active FLPs in the activation of dihydrogen to give the respective zwitterionic [P]H⁺/[B]H⁻ products.

A stable metal–organic framework pillared by Keggin-type polyoxometalate, Cu₆(Trz)₁₀(H₂O)₄[H₂SiW₁₂O₄₀]⋅8 H₂O (Trz=1,2,4-triazole) (1), has been prepared under hydrothermal condition. The 2D layer structure with a 22-member ring was formed by Cu²⁺ ions, which are connected with each other via the Trz ligands on the ab plane. Thus, the 2D layers are further interconnected through Keggin polyoxoanions to generate a 3D porous network with a small 1D channel. Moreover, the presence of polyoxoanions make it exhibit selective adsorption of water and proton-conducting properties. Additionally it showed efficient intrinsic peroxidase-like activity, providing a simple and sensitive colorimetric assay to detect H₂O₂.

Squaring up: A highly stable polyoxometalate-pillared metal–organic framework, which has been prepared by a hydrothermal method (see figure), exhibits selective adsorption of water, proton-conducting properties, and efficient intrinsic peroxidase-like activity, providing a simple and sensitive colorimetric assay for the detection of H₂O₂.

Ruthenium-catalyzed annulation of 1-naphthylsilanes with internal alkynes afforded silaphenalenes through cleavage of the CH bond at the 8-position of the naphthalene. [RuH₂(CO){P(p-FC₆H₄)₃}₃] efficiently catalyzed the reaction. The use of 1-naphthyldiphenylsilane as a substrate resulted in a better yield of the annulation product compared to the use of silanes with alkyl groups on the silicon atom. Internal alkynes with both aryl and alkyl groups were tolerated in this reaction.

Annulation rather than hydrosilylation: A ruthenium catalyst favored annulation products rather than hydrosilylation products in the reaction of 1-naphthylsilanes and alkynes. The annulation proceeded with selective cleavage of the CH bond at the 8-position of naphthalene. Substrate scope revealed that substituents on the silicon atom played a crucial role and the phenyl group helped to increase the yields.