Rational design and exploration of robust and low‐cost bifunctional oxygen reduction/evolution electrocatalysts are greatly desired for metal–air batteries. Herein, a novel high‐performance oxygen ...electrode catalyst is developed based on bimetal FeCo nanoparticles encapsulated in in situ grown nitrogen‐doped graphitic carbon nanotubes with bamboo‐like structure. The obtained catalyst exhibits a positive half‐wave potential of 0.92 V (vs the reversible hydrogen electrode, RHE) for oxygen reduction reaction, and a low operating potential of 1.73 V to achieve a 10 mA cm−2 current density for oxygen evolution reaction. The reversible oxygen electrode index is 0.81 V, surpassing that of most highly active bifunctional catalysts reported to date. By combining experimental and simulation studies, a strong synergetic coupling between FeCo alloy and N‐doped carbon nanotubes is proposed in producing a favorable local coordination environment and electronic structure, which affords the pyridinic N‐rich catalyst surface promoting the reversible oxygen reactions. Impressively, the assembled zinc–air batteries using liquid electrolytes and the all‐solid‐state batteries with the synthesized bifunctional catalyst as the air electrode demonstrate superior charging–discharging performance, long lifetime, and high flexibility, holding great potential in practical implementation of new‐generation powerful rechargeable batteries with portable or even wearable characteristic.
Bamboo‐like FeCo alloy encapsulated in nitrogen‐doped carbon nanotubes exhibits superior catalytic oxygen reduction and oxygen evolution performance than that of noble metal benchmarks, which benefits from the nitrogen‐rich and defect‐rich catalyst surface. The all‐solid‐state zinc–air batteries equipped by the synthesized materials show low charging/discharging overpotentials, long lifetime, and high flexibility, suitable for practical application.
Metal-free and controlled synthesis of sulfur-containing polymer is still a big challenge in polymer chemistry. Here, we report a metal-free, living copolymerization of carbonyl sulfide (COS) with ...epoxides via the cooperative catalysis of organic Lewis pairs including bases (e.g.: phosphazene, amidine, and guanidine) and thioureas as hydrogen-bond donors, afford well-defined poly(monothiocarbonate)s with 100% alternating degree, >99% tail-to-head content, controlled molecular weights (up to 98.4 kg/mol), and narrow molecular weight distributions (1.13-1.23). The effect of the types of Lewis pairs on the copolymerization of COS with several epoxides is investigated. The turnover frequencies (TOFs) of these Lewis pairs are as high as 112 h
at 25 °C. Kinetic and mechanistic results suggest that the supramolecular specific recognition of thiourea to epoxide and base to COS promote the copolymerization cooperatively. This strategy provides commercially available Lewis pairs for metal-free synthesis of sulfur-containing polymers with precise structure.
Clusteroluminescence (CL) and through‐space interactions (TSIs) of non‐conjugated molecules have drawn more attention due to their unique photophysical behaviors that are different from largely ...conjugated luminogens. However, achieving red and even near‐infrared (NIR) emission from such systems is still challenging due to the intrinsic drawbacks of non‐conjugated molecules and the lack of theories for structure–property relationships. In this work, six phenolic resins are designed and synthesized based on two molecule‐engineering strategies: increasing the number of TSIs units and introducing electron‐donating/‐withdrawing groups. All phenolic resins are verified as luminogens with CL property (CLgens), and the first example of CLgens with NIR emission (maximum emission wavelength ≥680 nm) and high absolute quantum yield (47 %) is reported. Experiments and theoretical analysis reveal that two TSIs types, through‐space locally excited state and through‐space charge transfer state, play essential roles in achieving CL from these non‐conjugated polymers, which could be manipulated via changing structural conformation and electron density or altering electron transition behaviors. This work not only provides an approach to manipulate TSIs and CL of non‐conjugated polymers but also endows commercially available phenolic resins with high practical value as luminescence materials.
Nonconjugated luminescent materials derived from well‐developed engineering plastics of phenolic resins could fluoresce from deep blue to the NIR region. This remarkable luminescence is attributed to through‐space interactions (TSIs) and can be manipulated using two molecule‐engineering strategies: increasing the number of TSIs units and introducing D/A groups. The NIR emission endows phenolic resins with practical value as luminescence materials and is a breakthrough in clusteroluminescence from nonconjugated materials.
There is an urgent need for highly effective therapeutic agents to interrupt the continued spread of SARS-CoV-2. As a pivotal protease in the replication process of coronaviruses, the 3CLpro protein ...is considered as a potential target of drug development to stop the spread and infection of the virus. In this work, molecular dynamics (MD) simulations were used to elucidate the molecular mechanism of a novel and highly effective non-covalent inhibitor, WU-04, targeting the SARS-CoV-2 3CLpro protein. The difference in dynamic behavior between the
apo
-3CLpro and the
holo
-3CLpro systems suggests that the presence of WU-04 inhibits the motion amplitude of the 3CLpro protein relative to the
apo
-3CLpro system, thus maintaining a stable conformational binding state. The energy calculations and interaction analysis show that the hot-spot residues Q189, M165, M49, E166, and H41 and the warm-spot residues H163 and C145 have a strong binding capacity to WU-04 by forming multiple hydrogen bonds and hydrophobic interactions, which stabilizes the binding of the inhibitor. After that, the resistance of WU-04 to the six SARS-CoV-2 variants (Alpha, Beta, Gamma, Delta, Lambda, and Omicron) and two other mainstream coronavirus (SARS-CoV and MERS-CoV) 3CLpro proteins was further investigated. Excitingly, the slight difference in energy values relative to the SARS-CoV-2 system indicates that WU-04 is still highly effective against the coronaviruses, which becomes crucial evidence that WU-04 is a pan-inhibitor of the 3CLpro protein in various SARS-CoV-2 variants and other mainstream coronaviruses. The study will hopefully provide theoretical insights for the future rational design and improvement of novel non-covalent inhibitors targeting the 3CLpro protein.
A novel non-covalent inhibitor, WU-04, inhibits several mainstream coronaviruses and is a pan-inhibitor of 3CLpro.
The preparation of perfectly alternating and regioslective copolymers derived from the copolymerization of carbonyl sulfide (COS) and epoxides by metal‐free Lewis pair catalysts composed of a Lewis ...base (amidine, guanidine, or quaternary onium salts) and a Lewis acid (triethyl borane) is described. Colorless and highly transparent copolymers of poly(monothiocarbonate) were successfully obtained with over 99 % tail‐to‐head content and high molecular weight (up to 92.5 kg mol−1). In most instances, oxygen–sulfur exchange reactions (O/S ERs), which would generate random thiocarbonate and carbonate units, were effectively suppressed. The turnover frequencies (TOF) of these Lewis pair catalyzed processes were as high as 119 h−1 at ambient temperature.
COS metal‐free is better: Using metal‐free Lewis pairs composed of triethylborane and various Lewis bases (LBs), colorless and highly transparent poly(monothiocarbonate)s were successfully obtained with over 99 % tail‐to‐head content and high molecular weight (up to 92.5 kg mol−1). The turnover frequency of these Lewis pair catalyzed processes were up to 119 h−1 at ambient temperature.
Omicron is a novel variant of SARS-CoV-2 that is currently spreading globally as the dominant strain. The virus first enters the host cell through the receptor binding domain (RBD) of the spike ...protein by interacting with the angiotensin-converting enzyme 2 (ACE2). Thus, the RBD protein is an ideal target for the design of drugs against the Omicron variant. Here, we designed several miniprotein inhibitors
to combat the SARS-CoV-2 Omicron variant using single- and double-point mutation approaches, based on the structure of the initial inhibitor AHB2. Also, two parallel molecular dynamics (MD) simulations were performed for each system to reproduce the calculated results, and the binding free energy was evaluated with the MM/PBSA method. The evaluated values showed that all inhibitors, including AHB2, M7E, M7E + M43W, and M7E + M43Y, were energetically more beneficial to the binding with the RBD than ACE2. In particular, the mutant inhibitor M7E + M43Y possessed the highest binding affinity to RBD and was selected as the most promising "best" inhibitor among all inhibitors. In addition, the combination of multiple analysis methods, such as free energy landscape analysis (FEL), principal component analysis (PCA), dynamic cross-correlation matrix analysis (DCCM), and hydrogen bond, salt bridge, and hydrophobic interaction analysis, also demonstrated that the mutations significantly affect the dynamical behavior and binding pattern of the inhibitor binding to the RBD protein. The current work suggested that miniprotein inhibitors can form stable complex structures with the RBD protein and exert a blocking or inhibitory effect on the SARS-CoV-2 variant Omicron. In conclusion, this study has identified several novel mutant inhibitors with enhanced affinity to the RBD protein, and provided potential guidance and insights for the rational design of therapeutic approaches for the new SARS-CoV-2 variant Omicron.
The fast and living ring‐opening polymerization (ROP) of propylene oxide (PO) by metal‐free catalysis is reported. By using triethyl borane (TEB) and organic Lewis bases (LBs, e.g.: phosphazene base, ...amidine and guanidine) as the catalysts, various alkyl alcohols can effectively initiate the ROP of PO, yielding tailor‐made poly(propylene oxide)s (PPOs) with high regioregularity, predictable molecular weights, and narrow dispersity approaching Poisson distribution. The TEB/LB catalysts present unprecedentedly high activity (turnover frequency of up to 7500 h−1) and a truly living character for the polymerization, as evidenced by kinetic studies that showed fast initiation and growth, unobserved chain‐transfer to PO, chain extension reactions, and the synthesis of various PPO‐based block copolymers with narrow dispersities (Đ<1.1).
Poisson project: The metal‐free, fast, and living ring‐opening polymerization of propylene oxide is performed by a unique masking anion strategy, yielding tailor‐made poly(propylene oxide)s with unprecedented activity, high regioregularity, predictable molecular weights, and narrow dispersity approaching Poisson distribution.
Molecular docking has become an increasingly important tool for drug discovery. In this review, we present a brief introduction of the available molecular docking methods, and their development and ...applications in drug discovery. The relevant basic theories, including sampling algorithms and scoring functions, are summarized. The differences in and performance of available docking software are also discussed. Flexible receptor molecular docking approaches, especially those including backbone flexibility in receptors, are a challenge for available docking methods. A recently developed Local Move Monte Carlo (LMMC) based approach is introduced as a potential solution to flexible receptor docking problems. Three application examples of molecular docking approaches for drug discovery are provided.
Materials exhibiting excitation wavelength‐dependent photoluminescence (Ex‐De PL) in the visible region have potential applications in bioimaging, optoelectronics and anti‐counterfeiting. Two ...multifunctional, chiral Au(NHC)2Au(CN)2 (NHC=(4R,5R)/(4S,5S)‐1,3‐dimethyl‐4,5‐diphenyl‐4,5‐dihydro‐imidazolin‐2‐ylidene) complex double salts display Ex‐De circularly polarized luminescence (CPL) in doped polymer films and in ground powder. Emission maxima can be dynamically tuned from 440 to 530 nm by changing the excitation wavelength. The continuously tunable photoluminescence is proposed to originate from multiple emissive excited states as a result of the existence of varied AuI⋅⋅⋅AuI distances in ground state. The steric properties of the NHC ligand are crucial to the tuning of AuI⋅⋅⋅AuI distances. An anti‐counterfeiting application using these two salts is demonstrated.
Ex‐De CPL: By modulating the strength of AuI⋅⋅⋅AuI and Coulombic interactions by adjusting steric hindrance of the ligand, together with the materials processing, the two chiral enantiomers of Au(NHC)2Au(CN)2 double salts in PMMA film or as ground powder exhibit mirror‐image excitation wavelength‐dependent photoluminescence (Ex‐De CPL).
Temperature sensors have great potential applications for the body temperature monitoring, it's a big challenge to prepare sensors with high sensitivity and maintaining adaptive properties for the ...long‐term applications. In this study, an organohydrogel for the temperature sensor is achieved via glycerol solvent replacement of water in the poly‐N‐acryloyl glycinamide (PNAGA)/carrageenans double network (DN) hydrogel. Owing to successful construction of strong multiple hydrogen bonding (H‐bonding) interactions among PNAGA chains and carrageenans, the PNAGA‐based glycerol gel (Gly‐gel) sensor exhibits excellent thermal stabilities, possesses high sensitivities (2% °C) resulted from the acceleration of mobility of ions at high temperature and shows high tensile strength of about 4 MPa without chemical crosslinkers (higher than most reported organohydrogel‐based temperature sensor) with self‐healable performance. In addition, the double network of Gly‐gel enables it excellent dual and triple shape memory performance with high fixing ratio (Rf, 88%), recovery ratio (Rr, 95%) under large deformations (above 80%) that are beneficial to the potential application in wearable devices. Different from previous temperature sensors, this work provides a facile approach to prepare overly sensitive temperature sensors with the combination of excellent thermal stability, high tensile strength and adaptive properties via the solvent replacement of hydrogel.
An organohydrogel‐based temperature sensor is achieved via glycerol solvent replacement of water in poly‐N‐acryloyl glycinamide/carrageenans DN hydrogel (Gly‐gel). The Gly‐gel sensor exhibits high sensitivities (2% °C−1) and shows high tensile strength of up to 4 MPa with self‐healable performance. The double network enables Gly‐gel excellent shape memory performance with high fixing ratio (Rf, 88%), recovery ratio (Rr, 95%).
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