What a turnover! An efficient chiral iridium catalyst that bears a tridentate spiro aminophosphine ligand catalyzes the asymmetric hydrogenation of ketones with excellent enantioselectivities (up to ...99.9 % ee) and extremely high turnover numbers (TONs; as high as 4 550 000).
The authors examine the enantioselective hydrogenation of enamines and imines in metal-catalyzed transitions. The enantioselective hydrogenation of several catalysts is also studied.
Organic n‐type materials (e.g., fullerene derivatives, naphthalene diimides (NDIs), perylene diimides (PDIs), azaacene‐based molecules, and n‐type conjugated polymers) are demonstrated as promising ...electron transport layers (ETLs) in inverted perovskite solar cells (p–i–n PSCs), because these materials have several advantages such as easy synthesis and purification, tunable frontier molecular orbitals, decent electron mobility, low cost, good solubility in different organic solvents, and reasonable chemical/thermal stability. Considering these positive factors, approaches toward achieving effective p–i–n PSCs with these organic materials as ETLs are highlighted in this Review. Moreover, organic structures, electron transport properties, working function of electrodes caused by ETLs, and key relevant parameters (PCE and stability) of p–i–n PSCs are presented. Hopefully, this Review will provide fundamental guidance for future development of new organic n‐type materials as ETLs for more efficient p–i–n PSCs.
Organic n‐type materials as electron transport layers (ETLs) in inverted perovskite solar cells (p–i–n PSCs) have attracted many scientists' attention, not only because of their several advantages, including easy synthesis, tunable frontier molecular orbitals, decent electron mobility, and reasonable chemical/thermal stability, but also because of their ability to make large‐scale solution‐processing p–i–n PSCs possible.
Tons of TONs: Chiral iridium catalysts bearing ligand 1 are highly efficient for the asymmetric hydrogenation of β‐substituted β‐ketoesters. The product β‐hydroxyesters are delivered in high yield ...with excellent enantioselectivities and high turnover numbers (TONs). cod= 1,5‐cyclooctadiene.
A Ni‐catalyzed hydroarylation of styrenes and 1,3‐dienes with organoboron compounds has been developed. The reaction offers a highly selective approach to diarylalkanes and allylarenes under ...redox‐neutral conditions. In this hydroarylation reaction, a new strategy that uses the proton of methanol to generate the active catalyst species Ni−H was developed. The Ni‐catalyzed hydroarylation, combined with a Ir‐catalyzed C−H borylation, affords a very efficient and straightforward access to a retinoic acid receptor agonist.
OH yeah: A nickel(0)‐catalyzed hydroarylation of alkenes with organoboron reagents using an alcohol OH group as the H‐atom source is reported. The reaction offers a highly selective approach to diarylalkanes and allylarenes under redox‐neutral conditions.
•This study examines the compressive and flexural behaviour of a new material mixture, RSRAC.•RSRAC with an optimal rubber content displays good compressive behaviour.•RSRAC is a more environmentally ...friendly alternative to normal rubber concrete for use in the flexural member.
Using recycled concrete and crumb rubber as aggregates to produce green concrete is a promising technology toward sustainability in the construction industry. In this study, the compressive and flexural behaviours of a new type of concrete material, rubber crumb and steel-fibre-reinforced recycled aggregate concrete (RSRAC), are investigated. To popularise the application of this new type of green building material, an experimental study was conducted to investigate the effect of the rubber content on the compressive and flexural behaviours of RSRAC. A total of 18 cubes (150mm) and 18 cylinders (150mm×200mm) were tested under axial compressive loading, and 18 prisms of 150×150×550mm were tested subjected to three-point bending. The crumb rubber content was varied in the investigation at levels of 0%, 4%, 8%, 12% and 16% by volume substitution of sand. Recycled concrete aggregate (RCA) was introduced into the concrete mixture by 100% volume substitution of natural coarse aggregate (NCA), and 1% volumetric quantity of steel fibre was added to the concrete mixture. The effect of the rubber content on the compressive and flexural strength, failure mode, modulus of elasticity and toughness of RSRAC was analysed. The results indicate that RSRAC with an optimal rubber content displays good compressive behaviour compared with normal NCA concrete. RSRAC is also a more environmentally friendly alternative to normal rubber concrete for use in theflexural members of concrete structures.
Radiation dosimeters displaying conspicuous response of irradiance are highly desirable, owing to the growing demand of monitoring high-energy radiation and environmental exposure. Herein, we present ...a case of dosimetry based on a discrete nanocluster, Th
(OH)
(O)
(H
O)
(TPC)
(HCOO)
∙4DMF∙H
O (Th-SINAP-100), by judiciously incorporating heavy Th
polynuclear centers as radiation attenuator and organic linkers as photo-responsive sensor. Interestingly, dual-module photochromic transitions upon multiple external stimuli including UV, β-ray, and γ-ray are integrated into this single material. The striking color change, and more significantly, the visible color transition of luminescence in response to accumulating radiation dose allow an on-site quantitative platform for naked-eye detection of ionization radiations over a broad range (1-80 kGy). Single crystal X-ray diffraction and density functional theory calculations reveal that the dual-module photochromism can be attributed to the π(TPC) → π*(TPC) intermolecular charge transfer driven by enhanced π-π stacking interaction between the adjacent TPC moieties upon irradiation.
A highly enantio‐ and regioselective hydrosulfonylation of 1,3‐dienes with sulfonyl hydrazides has been realized by using a palladium catalyst containing a monodentate chiral spiro phosphoramidite ...ligand. The reaction provided an efficient approach to synthetically useful chiral allylic sulfones. Mechanistic studies suggest that the reaction proceeds through the formation of an allyl hydrazine intermediate and subsequent rearrangement to the chiral allylic sulfone product. The transformation of the allyl hydrazine intermediate to the product is the enantioselectivity‐determining step.
A highly enantio‐ and regioselective hydrosulfonylation of 1,3‐dienes with sulfonyl hydrazides by using a palladium catalyst containing a monodentate chiral spiro phosphoramidite ligand is reported. The reaction provides a new strategy for the synthesis of chiral allylic sulfones in high enantioselectivity.
Covalent–organic frameworks (COFs), featuring structural diversity, framework tunability and functional versatility, have emerged as promising organic electrode materials for rechargeable batteries ...and garnered tremendous attention in recent years. The adjustable pore configuration, coupled with the functionalization of frameworks through pre‐ and post‐synthesis strategies, enables a precise customization of COFs, which provides a novel perspective to deepen the understanding of the fundamental problems of organic electrode materials. In this review, a summary of the recent research into COFs electrode materials for rechargeable batteries including lithium‐ion batteries, sodium‐ion batteries, potassium‐ion batteries, and aqueous zinc batteries is provided. In addition, this review will also cover the working principles, advantages and challenges, strategies to improve electrochemical performance, and applications of COFs in rechargeable batteries.
Covalent–organic frameworks (COFs) have been demonstrated to be promising electrode materials in rechargeable batteries due to their structural versatility and functional tunability. Aiming to attract more research interest in this field, the working mechanisms, strategies for enhancing the electrochemical performance, and challenges of COFs electrode materials for rechargeable batteries (lithium‐ion batteries, sodium‐ion batteries, potassium‐ion batteries, and aqueous zinc batteries) are presented.
A diastereoselective and enantioselective formal 4+1 ylide annulation of chiral sulfonium salts with various substituted α‐substituted nitroalkene leading to optically active isoxazoline N‐oxides ...using CF3SO3− as a key anion has been explored. The salient features of this methodology include high diastereo‐ and enantioselecties, easily available starting materials, mild reaction conditions, simple procedure, broad substrate scope and the isoxazoline N‐oxides are conveniently transformed into other functionalized compounds.
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