Catalyst-free system for reductive addition of terminal alkynes via 2,2′-dithiosalicylic acid in water

Green, practical, and efficient hydrothiolation of 2,2′-dithiosalicylic acid to terminal alkynes was found to proceed smoothly in water under mild reaction conditions with moderate to good yields. The use of metal catalysts and toxic solvents was avoided, and good to excellent stereoselectivity and regioselectivity were obtained. Herein, the reaction conditions and regioselectivity are discussed, and a preliminary reaction mechanism is proposed.     

CdS/PbS co-sensitized ZnO nanorods and its photovoltaic properties

Nanoparticles co-sensitized nanorods were designed and prepared by assembled CdS and PbS nanoparticles over ZnO nanorods using successive ionic layer adsorption and reaction (SILAR) method. The results showed that the uniform CdS and PdS nanoparticles could be deposited on the lateral and top of the ZnO nanorods when the precursor concentration was 0.05 M and 0.02 M, respectively. Solar cells based on CdS and PbS nanoparticles sensitized ZnO nanorods arrays were assembled successfully. A cell efficiency of 0.38% was obtained in ZnO/CdS/PbS in comparison with ZnO/PbS/CdS mainly due to the stepwise band edge structure constructed in this system except the coverage density of nanoparticles.     

The study of thermal decomposition kinetics of zinc oxide formation from zinc oxalate dihydrate

This study is devoted to the thermal decomposition of ZnC₂O₄·2H₂O, which was synthesized by solid-state reaction using C₂H₂O₄·2H₂O and Zn(CH₃COO)₂·2H₂O as raw materials. The initial samples and the final solid thermal decomposition products were characterized by Fourier transform infrared and X-ray diffraction. The particle size of the products was observed by transmission electron microscopy. The thermal decomposition behavior was investigated by thermogravimetry, derivative thermogravimetric and differential thermal analysis. Experimental results show that the thermal decomposition reaction includes two stages: dehydration and decomposition, with nanostructured ZnO as the final solid product. The Ozawa integral method along with Coats–Redfern integral method was used to determine the kinetic model and kinetic parameters of the second thermal decomposition stage of ZnC₂O₄·2H₂O. After calculation and comparison, the decomposition conforms to the nucleation and growth model and the physical interpretation is summarized. The activation energy and the kinetic mechanism function are determined to be 119.7 kJ mol^?1 and G(α) = ?ln(1 – α)^1/2, respectively.     

Synthesis of Triple‐Layered Ag@Co@Ni Core–Shell Nanoparticles for the Catalytic Dehydrogenation of Ammonia Borane

Triple‐layered Ag@Co@Ni core–shell nanoparticles (NPs) containing a silver core, a cobalt inner shell, and a nickel outer shell were formed by an in situ chemical reduction method. The thickness of the double shells varied with different cobalt and nickel contents. Ag_0.04@Co_0.48@Ni_0.48 showed the most distinct core–shell structure. Compared with its bimetallic core–shell counterparts, this catalyst showed higher catalytic activity for the hydrolysis of NH₃BH₃ (AB). The synergetic interaction between Co and Ni in Ag_0.04@Co_0.48@Ni_0.48 NPs may play a critical role in the enhanced catalytic activity. Furthermore, cobalt–nickel double shells surrounding the silver core in the special triple‐layered core–shell structure provided increasing amounts of active sites on the surface to facilitate the catalytic reaction. These promising catalysts may lead to applications for AB in the field of fuel cells.     

Determination of brazilein in rat plasma after intravenous administration by HPLC

Quantification of brazilein in rat plasma following intravenous administration was achieved by reversed-phase high-performance liquid chromatography using a mobile phase of acetonitrile-0.05 m potassium dihydrogen phosphate water (containing 0.5% triethylamine, pH 3.0; 20:80 v/v) and UV detection at 445 nm. The method was linear (determination coefficient, r(2) = 0.9992) within the tested range (0.313-5.0 microg/mL). Intra- and inter-day precision coefficients of variation and accuracy bias were acceptable (maximal CV value was 2.06% for intra-day and 1.71% for inter-day) over the entire range. The recoveries were 81.48, 84.61 and 82.83% for concentrations of 0.313, 1.25 and 5.0 microg/mL, respectively. The concentration-time curve of brazilein after intravenous administration was fitted to the two-compartment model. This is the first time that brazilein in rat plasma was detected by HPLC-UV method and its pharmacokinetic characteristic was comprehensively studied.     

Non-Covalent Interactions between Polyvinyl Chloride and Conjugated Polymers Enable Excellent Mechanical Properties and High Stability in Organic Solar Cells

The incorporation of insulating polymers into conjugated polymers has been widely explored as a strategy to improve mechanical properties of flexible organic electronics. However, phase separation due to the immiscibility of these polymers has limited their effectiveness. In this study, we report the discovery of multiple non-covalent interactions that enhances the miscibility between insulating and conjugated polymers, resulting in improved mechanical properties. Specifically, we have added polyvinyl chloride (PVC) into the conjugated polymer PM6 and observed a significant increase in solution viscosity, indicative of favorable miscibility between these two polymers. This phenomenon has been rarely observed in other insulating/conjugated polymer composites. Thin films of PM6/PVC exhibit a much-improved crack-onset strain of 19.35 %, compared to 10.12 % for pristine PM6 films. Analysis reveal that a “cyclohexyl-like” structure formed through dipole-dipole interactions and hydrogen bonding between PVC and PM6 acted as a cross-linking site in the thin films, leading to improved mechanical properties. Moreover, PM6/PVC blend films have demonstrated excellent thermal and bending stability when applied as an electron donor in organic solar cells. These findings provide new insights into non-covalent interactions that can be utilized to enhance the properties of conjugated polymers and may have potential applications in flexible organic electronics.