Chemistry of Materials
DOI: 10.1021/acs.chemmater.3c01476
Alkynyl‐protected Ag20Rh2 Nanocluster with Atomic Precision: Structure Analysis and Tri‐functionality Catalytic Application
We report a novel alkynyl-protected Ag20Rh2 bimetallic nanocluster, which possesses unique structure and displays excellent catalytic performance toward hydrogen evolution reaction, 4-nitrophenol reduction, and methyl orange degradation.
Abstract
We report the overall structure and trifunctionality catalytic application of an atomically precise alloy nanocluster of Ag20Rh2(C≡C-tBu)16(CF3CO2)6(H2O)2 (abbreviated as Ag20Rh2 hereafter). Ag20Rh2 has a twisted rod-like structure, where a Ag4@Rh2 kernel is connected by two twisted Ag8 cubes on two sides. Ag20Rh2 is a superatomic cluster with four free valence electrons, and it has characteristic absorbance feature. Interestingly, Ag20Rh2 exhibited superior catalytic performance than the larger AgRh nanoparticle counterparts in electrochemical hydrogen evolution reaction (HER), reduction of 4-nitrophenol, and the methyl orange degradation reaction. Such intriguing catalytic properties are attributed to the more exposed active sites from the ultrasmall nanoclusters than relatively large nanoparticles. This study not only enriches the family member of alkynyl-protected AgRh nanoclusters with atomic precision, but also highlights the great advantages of employing nanoclusters as efficient catalysts for multiple functionalities.
Stereoselective Synthesis of Pyrrolo/Pyrido[2,1‐a]isoindoles via Alkyne Iminium Ion Cyclization of Vinylogous Carbamates
![Stereoselective Synthesis of Pyrrolo/Pyrido[2,1-a]isoindoles via Alkyne Iminium Ion Cyclization of Vinylogous Carbamates](https://onlinelibrary.wiley.com/cms/asset/7fd4d633-e5d2-4908-b46d-8a779a5e9f93/asia202300626-toc-0001-m.png)
A diastereoselective synthesis of pyrrolo/pyridoisoindole via alkyne iminium ion cyclization of vinylogous carbamate is described. This protocol features a broad substrate scope and easy scalability. An unusual 1,3-alkyl shift is observed with the substrates bearing a strong electron-donating group at the phenyl ring attached to alkyne.
Abstract
An efficient, acid-mediated, intramolecular alkyne iminium ion cyclization of oxoisoindolidene for the diastereoselective synthesis of pyrrolo/pyridoisoindole is described. This protocol features broad substrate scope and easy scalability. An unusual N to C-1,3-alkyl shift is observed with substrates bearing strong electron donating group at the phenyl ring attached to alkyne with concomitant hydration of alkyne to the ketone.
Solid Electrolyte Interphase Architecture for a Stable Li‐electrolyte Interface
In this review, the strategies to fabricate effective solid electrolyte interphase (SEI) for a stable Li-electrolyte interface are summarized. The designed inorganic artificial SEI, organic artificial SEI, and hybrid artificial SEI can significantly improve the electrochemical performance of Li metal anode. The strategies provide insights into Li metal protection.
Abstract
Li metal anode has attracted extensive attention as the state-of-the-art anode material for rechargeable batteries. It is defined as the ultimate anode material for the high theoretical specific capacity (3860 mAh g−1) and the lowest negative electrochemical potential (−3.04 V vs. Standard Hydrogen Electrode). However, the uncontrolled Li dendrites and the spontaneous side reactions between Li and electrolytes hinder its commercialization. To overcome these obstacles, the optimized solid electrolyte interphase (SEI) with excellent performance was proposed by the artificial method. The improved performance includes high stability, ionic conductivity, compactness, and flexibility. In this review, the strategies for artificial SEI engineering in liquid and solid electrolytes are summarized. To fabricate an ideal artificial SEI, the component, distribution, and structure should be fully and reasonably considered. This review will also provide perspectives for the SEI design and lay a foundation for the future research and development of Li metal batteries.
Synthesis, Molecular Packing and Semiconductor Properties of V‐Shaped N‐Heteroacene Dimers
New V-shaped π-scaffolds are constructed by fusing two N-heteroacene units with either a rigid or flexible eight-membered ring. Their crystals exhibit interesting π-π interaction modes, which are dependent on the central connecting units and substituting groups. These π-π interactions between the V-shaped π-scaffolds have enabled the molecules to function as organic semiconductors in solution-processed field effect transistors.
Abstract
This article presents two groups of V-shaped π-scaffolds that consist of two N-heteroacene units fused with either a rigid or flexible eight-membered ring. These rigid and flexible N-heteroacene dimers were synthesized through the condensation of tetraphenylenetetraone with the corresponding diamine and the Pd-catalyzed cross-coupling of tetrabromodibenzo[a,e]cyclooctatetraene with the corresponding diamine, respectively. A comparison of electronic structures and properties of the two groups of V-shaped N-heteroacene dimers shows subtle difference between the rigid and flexible eight-membered ring linkers in forming extended π-systems. X-ray crystallography of these V-shaped molecules has revealed interesting π-π interaction modes, which are dependent on the central connecting units and substituting groups. These π-π interactions between the V-shaped π-scaffolds have enabled the molecules to function as organic semiconductors in solution-processed field effect transistors.
Design of Glycopolymers for Controlling the Interactions with Lectins
Carbohydrates are involved in our life activities through binding to corresponding lectins. Glycopolymer is one of the classes of the emerging materials in recent years that mimic the functions of the glycoconjugates on the cells. This review summarizes the research over the past decade on the design of glycopolymers with a focus on controlling the interactions with lectins.
Abstract
Carbohydrates are involved in life activities through the interactions with their corresponding proteins (lectins). Pathogen infection and the regulation of cell activity are controlled by the binding between lectins and glycoconjugates on cell surfaces. A deeper understanding of the interactions of glycoconjugates has led to the development of therapeutic and preventive methods for infectious diseases. Glycopolymer is one of the classes of the materials present multiple carbohydrates. The properties of glycopolymers can be tuned through the molecular design of the polymer structures. This review focuses on research over the past decade on the design of glycopolymers with the aim of developing inhibitors against pathogens and manipulator of cellular functions.
Heat‐ and Pressure‐driven Room‐temperature Polymorphic Transition Accompanied with Switchable SHG Signal in a New Chiral Hexagonal Perovskite
Herein, we report a new chiral hexagonal perovskite, (R-hmpi)[CdCl3] (1), which can be long-term stable yet easily interconvertible between two ordered crystalline phases (1 α and 1 β) at a pressure of ~12 MPa and a temperature of 120 °C. The two phases exhibit significantly distinct second-harmonic-generation signals because of different distorted degrees of inorganic chains.
Abstract
Endowing room-temperature polymorphs with both long-term stability and easy interconvertibility is a big challenge due to the complexity of intermolecular interactions. Herein, we present a chiral hexagonal perovskite (R-3-hydroxy-1-methylpiperidinium)[CdCl3] having two room-temperature crystalline forms featuring obviously distinct second-harmonic-generation (SHG) signals with a high switching contrast of ~18 times. The two room-temperature forms could be long-term stable yet easily interconvertible through an irreversible thermal-induced phase transition and a pressure-driven backward transition, by switching hydrogen bonds via collective reorientation of ordered homochiral cations. Based on the essential role of homochiral organic cations in inducing switchable hydrogen bond linkages, this present instance provides good evidence that relatively irregular organic cations could induce more obvious inorganic chain deformations, thus endowing polymorphs with significantly different SHG signals at room temperature.
Visible‐Light‐Mediated Synthesis of α‐Ketoamides via Oxidative Amination of 2‐Bromoacetophenones Using Eosin Y as a Photoredox Catalyst
A visible light-mediated photoredox synthesis of α-ketoamides has been accomplished via an oxidative amination of 2-bromoacetophenones.
Abstract
An oxidative amination of 2-bromoacetophenones has been accomplished to provide α-ketoamides by using photoredox catalysis with air as oxidant. The reactants are readily accessible, and the method is endowed with broad substrate scope and good functional group tolerance. The practicality of the approach is also shown by a gram-scale reaction.
Alkynyl‐Protected Bimetallic Nanoclusters with a Hybrid Mackay Icosahedral Ag42Cu12Cl Kernel and an Octahedral Ag22Cu12 Kernel
Two novel alkynyl-protected silver-copper nanoclusters (Ph4P)2[Ag22Cu12(C≡CR)28] and (Ph4P)3[Ag42Cu12Cl(C≡CR)36] (Ag22Cu12 and Ag42Cu12Cl) were obtained by using a weak reducing agent diphenylsilane (Ph2SiH2). For the first time, a hybrid 55-atom two-shell Mackay icosahedron was found in Ag42Cu12Cl. The incorporation of a chloride in the metal icosahedron contributes to the stability of the cluster due to electronic and geometric factors.
Abstract
A facile strategy that directly reduces alkynyl-silver precursors and copper salts for the synthesis of bimetallic nanoclusters using the weak reducing agent Ph2SiH2 is demonstrated. Two alkynyl-protected concentric-shell nanoclusters, (Ph4P)2[Ag22Cu12(C≡CR)28] and (Ph4P)3[Ag42Cu12Cl(C≡CR)36] (Ag22Cu12 and Ag42Cu12Cl, R=bis(trifluoromethyl)phenyl), were successfully obtained and characterized by single-crystal X-ray diffraction and electro-spray ionization mass spectrometry. For the first time, a hybrid 55-atom two-shell Mackay icosahedron was found in Ag42Cu12Cl, which is icosahedral M54Cl instead of M55. The incorporation of a chloride in the metal icosahedron contributes to the stability of the cluster from both electronic and geometric aspects. Alkynyl ligands show various binding-modes including linear “RC≡C−Cu−C≡CR” staple motifs.
Synthesis of Difluoromethylated Alkenes via Copper‐Catalyzed Protodefluorination of β‐(Trifluoromethyl)styrenes
Under typical copper-catalyzed hydroboration conditions, β-(trifluoromethyl)styrenes demonstrate unusal reactivities by forming difluoromethylated alkenes via a net protodefluorination process. This is also distinct from trifluoromethyl alkenes with alkyl substituents where defluoroborylation products predominate.
Abstract
Under typical copper-catalyzed hydroboration conditions, β-(trifluoromethyl)styrenes demonstrate unusal reactivities by forming difluoromethylated alkenes via a net protodefluorination process. This is also distinct from trifluoromethyl alkenes with alkyl substituents where defluoroborylation products predominate.