Search

Building up new and efficient methods for the controlled conversion of carboxylic acids to aldehydes is important. Herein, we report a rapid, modular and scalable method for the conversion of carboxylic acids to aldehydes using pinacolborane at ambient temperature, in which a triflylpyridinium reagent is used. The conversion of carboxylic acid to intermediate acylpyridinium by triflylpyridinium is new. A binary pyridine‐coordinated boronium complex is generated after reduction. The unprecedented reduction of the acylpyridinium by HBpin opens up a practically direct synthesis of aldehydes from carboxylic acids. Theoretical studies indicate that the reduction of acylpyridinium requires a lower activation free energy than that of the product aldehyde. The synthetic advantage of this protocol is further highlighted by the scalable synthesis of aldehyde via continuous flow process. Configuration retention for chiral acids are presented in those syntheses. [ABSTRACT FROM AUTHOR]

Building up new and efficient methods for the controlled conversion of carboxylic acids to aldehydes is important. Herein, we report a rapid, modular and scalable method for the conversion of carboxylic acids to aldehydes using pinacolborane at ambient temperature, in which a triflylpyridinium reagent is used. The conversion of carboxylic acid to intermediate acylpyridinium by triflylpyridinium is new. A binary pyridine‐coordinated boronium complex is generated after reduction. The unprecedented reduction of the acylpyridinium by HBpin opens up a practically direct synthesis of aldehydes from carboxylic acids. Theoretical studies indicate that the reduction of acylpyridinium requires a lower activation free energy than that of the product aldehyde. The synthetic advantage of this protocol is further highlighted by the scalable synthesis of aldehyde via continuous flow process. Configuration retention for chiral acids are presented in those syntheses. [ABSTRACT FROM AUTHOR]

Traditional lithium‐ion batteries cannot meet the ever‐increasing energy demands due to the unsatisfied graphite anode with sluggish electrochemical kinetics. Recently, the perovskite material family as anode attracts growing attention due to their advantages on specific capacity, rate capability, lifetime, and safety. Herein, a double perovskite La2MnNiO6 synthesized by solid‐state reaction method as a high‐performance anode material for LIBs is reported. La2MnNiO6 with an average operating potential of <0.8 V versus Li+/Li exhibits a good rate capability. Besides, the Li|La2MnNiO6 cells perform long cycle life without decay after 1000 cycles at 1C and a high cycling retention of 93% is observed after 3000 cycles at 6C. It reveals that this material maintains stable perovskite structure with cycling. Theoretical calculations further demonstrate the high electronic conductivity, low diffusion energy barrier, and structural stability of the lithiated La2MnNiO6. This study highlights the double perovskite type material as a promising anode for next‐generation batteries. [ABSTRACT FROM AUTHOR]

The role of mixed-valence structure in colossal dielectric constant ( CDC) behavior has been investigated in LaFeO3 ceramics by tuning the ratio of Fe2+/Fe3+ through substituting Al for Fe. The ratio of Fe2+/Fe3+ is decreased gradually from 1.0 to 0.0 by increasing the concentration of Al3+. Two clear-cut correlations have been found: (i) the relationship between the CDC behavior and the ratio of Fe2+/Fe3+ follows an exponential function and (ii) the activation energy of the polaron relaxation is proportional to [ABSTRACT FROM AUTHOR]

By means of dielectric permittivity, electric modulus and impedance, the dielectric properties of LiF single crystals were investigated in the temperature range of 30°C-800°C and frequency range of 50 Hz-10 MHz. Two thermally activated relaxations, R1 and R2, were observed. The relaxation R1 showing activation energy around 0.8 eV was found to be related to the Li-ion diffusion in the crystal. The relaxation R2 contains three Arrhenius segments, the low-, mid-, and high-T segments, separated by boundary temperatures of 325°C and 425°C. These segments in the order of ascending temperature were found to be associated with F3, F3+ centers, F2 centers, and F centers, respectively. [ABSTRACT FROM AUTHOR]