Science China Chemistry最新文献

A series of novel atropisomeric diphosphine ligands termed TanPhos were designed and synthesized, which has a smaller bite angle compared with that of other ligands such as BINAP. TanPhos showed high reactivity and enantioselectivity in the rhodium-catalyzed asymmetric hydrogenation of a-dehydro amino ketones, and up 99% yield and 99% ee were obtained for a wide range of chiral α-amino ketones.

Oxocarbons (C_nO_n, n=3, 4, 5, 6, …) are a series of compounds that are only composed of carbonyl groups. The highly electrophilic carbon atoms in C_nO_n make their poor stability toward H₂O, and thus the synthesis of C_nO_n is very challenging. Here an oxidation-dehydration method is developed to successfully synthesize C₄O₄ and C₅O₅. The combination of nuclear magnetic resonance (¹³C NMR, ¹H NMR), mass spectra, and infrared spectra unambiguously proves the exact chemical structure of C₄O₄ and C₅O₅. When used as a cathode material in lithium-ion batteries (LIBs), C₅O₅ could deliver a high discharge capacity of 698 mAh g^-1 (corresponding to an energy density of 1,256 Wh kg^-1_C5O5). Furthermore, ex-situ infrared spectra and density functional theory (DFT) calculations demonstrate that the carbonyl groups are redox active sites during discharge and charge processes. This work paves the way to achieve the synthesis and battery application of oxocarbons.

Significant advancements have been achieved in the field of C,C-palladacycles functionalization in recent decades, which have greatly contributed to the synthesis of intricate drug molecules, natural products, innovative materials, and chiral ligands. Additionally, these advancements have led to the establishment of highly efficient and atom-economic synthetic processes. Based on the differences in the C–Pd bonds, C, C-palladacycles can be further classified into several main types: C(aryl), C(alkyl)-, C(aryl), C(aryl)-, C(aryl), C(vinyl)-, and C(alkyl), C(carbonyl)-palladacycles. This minireview will highlight the recent advances in the synthesis of functional molecules through the functionalization of different C,C-palladacycles, and we hope this survey will inspire future strategic developments for C,C-palladacycle catalysts and their synthetic application.

The divergent reductive cross-coupling with an ambident electrophile is rare. Previously, we demonstrated a nickel-catalyzed reductive 2-pyridination of aryl iodides with difluoromethyl 2-pyridyl sulfone (2-PySO₂CF₂H) via selective C(sp²)–S bond cleavage of the sulfone by using a phosphine ligand. In this communication, we report a novel nickel-catalyzed reductive coupling of aryl iodides and 2-PySO₂CF₂H reagent, which constitutes a new method for aromatic difluoromethylation. The use of a tridentate terpyridine ligand is pivotal for the selective C(sp³)–S bond cleavage of the sulfone. This method employs readily available nickel catalyst and 2-PySO₂CF₂H as the difluoromethylation reagent, providing a facile access to difluoromethylarenes under mild reaction conditions without pre-generation of arylmetal reagents.

A green method for synthesis of nitriles from aldehydes and ammonium salts under air is developed under extremely mild conditions, i.e., 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) as a photocatalyst, 2,2,6,6-tetrametylpiperidine-1-oxyl (TEMPO) as a cocatalyst, and oxygen (ambient air) as the terminal oxidant, visible light irradiation of substrate solutions, producing the desired nitriles with excellent yields. The reaction involves two distinct transformations, imine formation between an aldehyde and an ammonium salt and photocatalytic oxidation of the formed imine by air to a nitrile.

Palladium-catalyzed allylic alkylation enabled by ketone umpolung via Pudovik addition/[1,2]-phospha-Brook rearrangement with phosphites has been developed. The protocol offers a straightforward method for the synthesis of potentially bioactive homoallylic alcohol phosphonates in an efficient and economical way. This cascade reaction proceeds under mild conditions with excellent functional group compatibility. Furthermore, the catalytic asymmetric version has also been explored.

The anodic oxygen evolution reaction (OER) can be combined with various cathodic reactions to enable the electrochemical synthesis of diverse chemicals and fuels, particularly in water electrolysis for hydrogen production. It is however exhibiting a high overpotential due to the sluggish four-electron transfer process, which is considered the decisive reaction in energy conversion systems. In recent years, metal-organic frameworks (MOFs) have emerged as the ideal catalysts for accelerating OER. This is primarily because of their orderly porous architecture, structural tailorability, and compositional diversity. This review systematically summarizes the recent research progress in pristine MOF electrocatalysts for OER, which covers the construction strategies and electrocatalytic performance of more than eight types of MOFs. Additionally, the partial/complete structural reconstructions and their effects on MOF-based OER electrocatalysts are highlighted. In particular, the development process of “discovery, explanation, and utilization” for the structural reconstructions of MOF electrocatalysts is outlined. Furthermore, the catalytic mechanisms are elaborated in detail, aiming to provide insight into the rational design and performance optimization of MOF-based OER electrocatalysts. The challenges and future perspectives of MOF-based OER electrocatalysts for industrial applications are also discussed.

Clustered regularly interspaced short palindromic repeat (CRISPR) has been gaining much attention in the modern medical field and has been widely used for the diagnosis and treatment of diseases in recent years. In this review, we will introduce the application of CRISPR in disease diagnosis and treatment, including its use in detecting pathogens, gene mutations, and genetic diseases, as well as its application in gene therapy for single-gene diseases, cancer, viral infectious diseases, and cardiovascular diseases. Additionally, we will discuss the potential future directions and challenges of CRISPR in the diagnosis and treatment of diseases, and provide a thorough overview of the ways in which CRISPR is used for diagnosing and treating diseases.

The medium-bandgap polymerized small molecule acceptors (PSMAs) have broad application scenarios. However, the effort in the molecular design of the high-performance medium-bandgap PSMAs is limited. In this article, we introduce alkoxy groups as outer side chains and as substituents of the thiophene π-bridges of the high-performance PSMA PY-IT to synthesize a medium-bandgap PSMA PO-TO. Due to that the non-covalent interaction between the alkoxy groups and the terminal groups of the small molecule acceptor (SMA) unit can weaken the intramolecular charge transfer (ICT) effect, the bandgap of PO-TO is enlarged and its absorption is blue-shifted compared with PY-IT, while the absorbance of PO-TO solution and film is enhanced significantly compare with that of PY-IT. When blended PO-TO with the polymer donor PBQx-TF, the corresponding all-polymer solar cells (all-PSCs) exhibit an open-circuit voltage (V_oc) exceeding 1.04 V with a power conversion efficiency (PCE) of 13.75%. Furthermore, PO-TO was used as the third component to fabricate ternary all-PSCs with PBQx-TF as the polymer donor and PY-IT as the main polymer acceptor, and the ternary all-PSCs based on PBQx-TF:PY-IT:PO-TO (1:1:0.2, w/w/w) demonstrated a high PCE of 17.71% with simultaneously improved V_oc of 0.940 V, short-circuit current density (J_sc) of 24.60 mA cm⁻² and fill factor (FF) of 76.81%. In comparison, the binary all-PSCs based on PBQx-TF:PY-IT showed a PCE of 16.77%. This result indicates that introducing alkoxy groups is a promising strategy for synthesizing high-performance medium-bandgap PSMAs.