Design, Synthesis, Anti-Tomato Spotted Wilt Virus Activity, and Mechanism of Action of Thienopyrimidine-Containing Dithioacetal Derivatives

Currently, there is insufficient viricide to effectively control tomato spotted wilt virus (TSWV). To address this pending issue, a series of thienopyrimidine-containing dithioacetal derivatives were prepared and tested for their anti-TSWV activities. A subsequent three-dimensional quantitative structure–activity relationship was constructed to indicate the development of optimal compound 35. The obtained compound 35 had excellent anti-TSWV curative, protective, and inactivating activities (63.0, 56.6, and 74.1%, respectively), and the EC50 values of protective and inactivating activities of compound 35 were 252.8 and 113.5 mg/L, respectively, better than those of ningnanmycin (284.8 and 144.7 mg/L) and xiangcaoliusuobingmi (624.9 and 300.0 mg/L). In addition, the anti-TSWV activity of compound 35 was associated with defense-related enzyme activities, enhanced photosynthesis, and reduced stress response, thereby enhancing disease resistance

Design, Synthesis, Anti-Tomato Spotted Wilt Virus Activity, and Mechanism of Action of Thienopyrimidine-Containing Dithioacetal Derivatives

Currently, there is insufficient viricide to effectively control tomato spotted wilt virus (TSWV). To address this pending issue, a series of thienopyrimidine-containing dithioacetal derivatives were prepared and tested for their anti-TSWV activities. A subsequent three-dimensional quantitative structure–activity relationship was constructed to indicate the development of optimal compound 35. The obtained compound 35 had excellent anti-TSWV curative, protective, and inactivating activities (63.0, 56.6, and 74.1%, respectively), and the EC50 values of protective and inactivating activities of compound 35 were 252.8 and 113.5 mg/L, respectively, better than those of ningnanmycin (284.8 and 144.7 mg/L) and xiangcaoliusuobingmi (624.9 and 300.0 mg/L). In addition, the anti-TSWV activity of compound 35 was associated with defense-related enzyme activities, enhanced photosynthesis, and reduced stress response, thereby enhancing disease resistance

Synthesis, Antiviral Activity, and Mechanisms of Purine Nucleoside Derivatives Containing a Sulfonamide Moiety

Novel purine nucleoside derivatives containing a sulfonamide moiety were prepared, as well as their antiviral activities against potato virus Y (PVY), cucumber mosaic virus (CMV), and tobacco mosaic virus (TMV) were evaluated. The antiviral mechanisms of the compounds were investigated. Results showed that most of the compounds had good antiviral activities. Compound 5 at 500 μg/mL exhibited excellent curative and protective activities of 52.5% and 60.0% and of 52.0% and 60.2% for PVY and CMV, respectively, which are higher than those of ningnanmycin (48.1%, 49.6%; 45.3%, 47.7%), ribavirin (38.3%, 48.2%; 40.8%, 45.5%), and chitosan oligosaccharide (32.5%, 33.8%; 35.1%, 34.6%). Moreover, compound 5 displayed good inactivating activity against TMV, with an EC50 value of 48.8 μg/mL, which is better than that of ningnanmycin (84.7 μg/mL), ribavirin (150.4 μg/mL), and chitosan oligosaccharide (521.3 μg/mL). The excellent antiviral activity of compound 5 is related to its immune induction effect which can regulate the physiological and biochemical processes in plants, including defense-related enzyme activities, defense-related genes, and photosynthesis-related proteins. These results indicate that purine nucleoside derivatives containing a sulfonamide moiety are worthy of further research and development as new antiviral agents

Pressure Dependence of Structural Behavior and Electronic Properties in Double Perovskite Ba₂SmSbO₆

Understanding the structural behavior of double perovskites plays a pivotal role in optimizing their optical, electrical, and magnetic properties, especially when the effects of external parameters are considered. In this work, we report the high-pressure phase transition, the light absorption, and the bandgap of double perovskite Ba2SmSbO6 investigated by using in situ high-pressure synchrotron X-ray diffraction and Raman and ultraviolet–visible (UV–vis) absorption spectroscopy measurements up to 40 GPa. We found that pressure induces the phase transition from a cubic Fm-3m to a tetragonal I4/m at 8.6–12.8 GPa, as accompanied by the splitting and broadening of the diffraction peaks. The evolution of various modes in the Raman spectra and the enthalpy calculations support the phase transition of Ba2SmSbO6 under compression. The analysis of UV–vis absorption spectroscopy reveals that the bandgap as a pressure of function is closely related to the phase transition. Calculation results demonstrate that the pressure-induced variation of the electronic structure mainly stems from the contribution of conduction states in Ba2SmSbO6. Our investigations provide a fundamental understanding of the structure–property modulation in Ba2SmSbO6 under high pressure and will functionalize a new applicationpressure sensor

Pressure-Quenched Superconductivity in Weyl Semimetal NbP Induced by Electronic Phase Transitions under Pressure

The TaAs family (NbAs, TaAs, NbP, TaP) are kinds of Weyl semimetals with lots of novel properties, thus attracting considerable attention in recent years. Here, we systematically studied the Weyl semimetal NbP up to 72 GPa through the resistivity, Raman spectra, X-ray diffraction measurements, and first-principles density functional theory (DFT) calculations. A pressure-induced semimetal–metal transition was observed at ∼36 GPa, which was further confirmed by the DFT calculations. With further compression up to 52 GPa, a superconducting state was observed. Interestingly, the Tc increases significantly upon decompression and shows a dome-shaped trend as a function of pressure. Surprisingly, the pressure-induced superconductivity can be quenched to ambient pressure, and all transitions under pressure do not involve any structural change. Our work not only depicts a phase diagram of the NbP system under high pressure but also provides a new experimental insight for superconductivity in Weyl semimetals

Twinning Engineering of Platinum/Iridium Nanonets as Turing-Type Catalysts for Efficient Water Splitting

The twin boundary, a common lattice plane of mirror-symmetric crystals, may have high reactivity due to special atomic coordination. However, twinning platinum and iridium nanocatalysts are grand challenges due to the high stacking fault energies that are nearly 1 order of magnitude larger than those of easy-twinning gold and silver. Here, we demonstrate that Turing structuring, realized by selective etching of superthin metal film, provides 14.3 and 18.9 times increases in twin-boundary densities for platinum and iridium nanonets, comparable to the highly twinned silver nanocatalysts. The Turing configurations with abundant low-coordination atoms contribute to the formation of nanotwins and create a large active surface area. Theoretical calculations reveal that the specific atom arrangement on the twin boundary changes the electronic structure and reduces the energy barrier of water dissociation. The optimal Turing-type platinum nanonets demonstrated excellent hydrogen-evolution-reaction performance with a 25.6 mV overpotential at 10.0 mA·cm–2 and a 14.8-fold increase in mass activity. And the bifunctional Turing iridium catalysts integrated in the water electrolyzer had a mass activity 23.0 times that of commercial iridium catalysts. This work opens a new avenue for nanocrystal twinning as a facile paradigm for designing high-performance nanocatalysts

Chemical Polishing of Perovskite Surface Enhances Photovoltaic Performances

The benefits of excess PbI2 on perovskite crystal nucleation and growth are countered by the photoinstability of interfacial PbI2 in perovskite solar cells (PSCs). Here we report a simple chemical polishing strategy to rip PbI2 crystals off the perovskite surface to decouple these two opposing effects. The chemical polishing results in a favorable perovskite surface exhibiting enhanced luminescence, prolonged carrier lifetimes, suppressed ion migration, and better energy level alignment. These desired benefits translate into increased photovoltages and fill factors, leading to high-performance mesostructured formamidinium lead iodide-based PSCs with a champion efficiency of 24.50%. As the interfacial ion migration paths and photodegradation triggers, dominated by PbI2 crystals, were eliminated, the hysteresis of the PSCs was suppressed and the device stability under illumination or humidity stress was significantly improved. Moreover, this new surface polishing strategy can be universally applicable to other typical perovskite compositions