Science China Chemistry最新文献

Chirality transformation is a basic, attractive, and important strategy for obtaining enantioenriched products with desired chiral elements. The reported chirality conversion reaction often involves the process from one type of chirality to another one. To better utilize the chirality transformation strategy for obtaining two or more products with different chiral elements in a single reaction, a new method of kinetic resolution accompanied by a chirality transformation protocol is proposed and successfully realized in this study. This process is used for the asymmetric oxidation of phenol compounds along with the kinetic resolution of oxaziridines. A wide scope of products, including axially chiral phenols, oxaziridines, and α-hydroxyl cyclic ketones were smoothly obtained in high levels of yields and enantioselectivities in the developed method. These products can be readily used for the synthesis of various types of chiral ligands, which are potential choices for other catalytic asymmetric reactions.

The reactive oxygen species (ROS) generation from photosensitizer in photodynamic therapy (PDT) is limited by tumor hypoxia. Even type-I photosensitizers, e.g., sulfur-substituted Nile blue, still rely on oxygen as the main center for transferring electrons to generate ROS. Cutting off the pathway of oxygen consumption in tumor can help photosensitizers overcome the limitation of low oxygen, in order to efficiently generate more ROS. It is known that glycolysis inhibitor 3-bromopyruvic acid (3-BP), which could specially target mitochondria, can provide more oxygen by inhibiting oxidative phosphorylation. Herein, we successfully designed and synthesized a new 3-BP-coupled sulfur-substituted Nile blue as prodrug (NBBP) for chemical/photodynamic synergistic therapy. Major results indicated that the protons in tumor catalyzed the hydrolysis of NBBP, inhibited photoinduced electron transfer between 3-BP and the photosensitizer in NBBP and further assisted the photosensitizer to be localized in mitochondria, utilizing local oxygen as much as possible and kill tumor cells more efficiently. Moreover, the glycolysis inhibition-induced autophagy was combined with PDT-induced autophagy, which could promote the deaths of tumor cells. Unlike other remedies exploiting nanomaterials, this construction method of NBBP achieves the efficient synergy of photodynamic therapy and glycolysis inhibition, stronger than their theoretical addition, in spatiotemporal dimensions. Our study provides not only a highly efficient platform for tumor therapy but also a design approach for prodrugs with synergistic effects.

Metal-organic nanosheets (MONs) as a novel material with tunable pore structures and low mass transfer resistance, have emerged as molecular sieves for the separation of gases and liquids. In theory, they can also serve as ion sieves for lithium metal batteries (LMBs), realizing the high-energy and dendritic free LMBs. However, there are rarely relevant reports, because it is difficult to simultaneously balance efficient ion sieving ability, high ion passing rate and high electrochemical stability. Here, we synthesized a stable ultrathin MON [Zn₂(Bim)₄] ([Zn₂(Bim)₄] Nanosheet, HBim = benzimidazolate), which can achieve both efficient lithium ion sieving ability, high lithium ion passing rate and high electrochemical stability at the same time. The separator assembled by this MON exhibits high Li⁺ transfer number of 0.81 due to the accurate lithium ion and anion/solvent separation. The battery containing such separator shows high lithium ionic conductivity of 0.74 mS cm⁻¹ and low activation energy of 0.099 eV, which can be attributed to the nanometer level thickness and the ion sieving effect. What is more, we realized the application of MONs-based ion sieves in LMBs with intercalation cathodes for the first time. And the LiFePO₄∣Li battery with as-assembled separator demonstrates improved Coulombic efficiency (> 99%) and significantly extended cycling life (> 1600 cycles) with 80% capacity retention.

Seawater electrolysis for green hydrogen production is one of the key technologies for achieving carbon neutrality. However, in anode systems, the chloride ions (Cl⁻) in seawater will trigger an undesired chlorine evolution reaction (CER) that competes with an oxygen evolution reaction (OER), resulting in inferior OER activity and selectivity. Besides, the corrosive Cl⁻ and its derivative products will corrode anodes during seawater electrolysis, leading to poor stability. Therefore, great efforts have been devoted to developing efficient strategies for chlorine inhibition to improve the activity, selectivity, and stability of anode materials. Herein, focusing on chlorine inhibition, we present a mini review to comprehensively and concisely summarize the recent progress in anode systems for boosting seawater electrolysis. In particular, two strategies of physical and chemical regulation to inhibit Cl⁻ are summarized in some representative cases. Finally, some challenges and future opportunities in anode systems for seawater electrolysis are prospected. This mini review aims to shed light on designing highly efficient anode materials for seawater electrolysis.

Realizing simultaneous adjustment of energy levels and work functions in two-dimensional/three-dimensional (2D/3D) perovskite solar cells (PSCs) is a challenge. Here, a pseudohalide 3,5-bis (trifluoromethyl) benzylammonium tetrafluoroborate (TF-PMABF₄) was used to react with unreacted PbI₂ on the surface of 3D bulky perovskite to form a mixed halide of 2D perovskite denoted (TF-PMA)₂FA₂Pb₃I₈(BF₄)₂. This novel 2D/3D perovskite enables the simultaneous adjustment of energy levels and work functions on the surface of active layers. Due to the significantly enhanced quality of 2D/3D perovskite film, decreased surface defects and increased charge carrier lifetime, the 2D/3D PSCs exhibit an outstanding power conversion efficiency (PCE) of 25.15% and a high V_OC of 1.194 V. Importantly, 2D/3D PSCs exhibit remarkable enhancements in environmental stability, unencapsulated devices retaining more than 90% of their initial PCE at 50% humidity for 2,280 h.

Unveiling the role of weak non-covalent forces in chiral self-assembly is pivotal in the design and fabrication of functional chiroptical materials. The nature of arene-perfluoroarene (AP) force is the electrostatic attraction between π-hole and π planes of perfluoroarenes and polyaromatic hydrocarbons (PAHs), which is emerging in constructing supramolecular motifs and coassembled optical devices. In this work, we reveal the potential of AP forces in building diversified levels of chiral coassemblies adaptive to the geometries of PAHs. The naphthalene-F₈ was covalently conjugated with a chiral amine, which folded into a semi-rectangular geometry via two intramolecular F⋯H bonds. PAHs of naphthalene, anthracene, pyrene, carbazole, perylene and benzoperylene were introduced to afford coassemblies in the crystalline state. X-ray structures suggest the formation of supramolecular boxes that encapsulate the PAHs with a 2:1 stoichiometric ratio, as well as the formation of consecutive layered ladders with a 1:1 stoichiometric ratio. The preference is adaptive to the geometries of PAHs, and experimental and computational results evidenced the ladder structures possess strong binding affinity. On this top, the selective chiral recognition in the mixtures of PAHs was realized, which shows promising applications in the separation of PAHs and rational design of crystalline chiroptical materials.

Organic room temperature phosphorescence (RTP) materials have potential applications in information technology and bioimaging. However, the precise control of the afterglow in reversible manners remains challenging for organic matters. Here, we report a kind of organic RTP material fabricated by simple heating mixtures of tartaric acid (TA) and aromatic acids, which can switch their phosphorescence by laser. Those mixtures show tunable phosphorescence from indigo to orange with phosphorescence efficiency of up to 53.99% due to locking different organic luminogens by the TA-formed matrix through the non-covalent interactions. The afterglow of those materials lasts a few seconds and disappears by water fumigation, which can be repeated in response to wet/heat stimuli. With drop-casting those materials on glass slides, a laser-repatternable phosphorescence is achieved by facile laser direct writing and quenched by water cyclically. Those results open the opportunity for the design of smart stimuli-responsive phosphorescence materials from sustainable natural products.

The chemoselective epoxidation of electron-deficient olefins in the presence of electron-rich alkene moieties is reported. This chemoselective epoxidation strategy undergoes a conjugated olefin epoxidation and BHT hydroxylation process to give various useful oxiranes in high yields, especially for the 2-substituted 2-trifluoromethyloxiranes. Importantly, this protocol features mild conditions, is transition-metal free, operationally simple, and gram-scalable, and tolerates diverse functional groups. Drug candidate HSD-16 is synthesized smoothly by this protocol. Mechanism studies indicate molecular oxygen is the terminal oxidant and the O-source of the oxiranes.

The synthesis and modification of peptides occupy a unique position in the field of drug development, and the functionalization of amino acids is a valuable strategy as an alternative to peptide modification. Currently, the development of tyrosine (Tyr) as a target amino acid is a major challenge in the field of chemistry. Herein, we report an electrochemical radical coupling reaction of labeling tyrosine-containing active drugs and peptides with thiocarbamate derivatives for the first time. This tri-component, one-pot reaction can be performed smoothly under simple, gentle, and clean electrochemical conditions and is suitable for the functionalization of various Tyr-containing drug molecular derivatives and peptides.