CONDENSATION OF 1,2-DIAMINES AND CARBOXYLICACIDS UNDER MICROWAVE IRRADIATION

A facile method of preparation of benzimidazoles by microwave irradiation was described. The mixtures of o-phenylenediamine and carboxylic acids were heated by microwave irradiation, to give 2-substituted benzimidazoles with yields of 49%～93%. The reaction time was shortened to 3～6 min. However, the reaction of ethylenediamine with carboxylic acids did not give imidazoles but the N,N-diacyl ethylenediamines. The alphatic diamines lacked the activity to form imidazole ring. With adipic acid, intermolecular acylation took place to afford poly(ethylene adipamide).

Green synthesis of multifunctional carbon dots for anti-cancer and anti-fungal applications

Carbon dots(CDs)have become popular nanomaterials in biomedical and agricultural fields.Herein we synthesized multifunctional CDs which showed anti-cancer and anti-fungal activities.The low cytotoxicity,stable fluorescence and high photothermal conversion efficiency enable the CDs with imagingguided photothermal therapy.The CDs also exhibited intrinsic anti-fungal activity even at a low concentration,i.e.,40 mg·L^(-1) of CDs induced 20%mortality in cucumber downy mildew.Moreover,the largeπ-conjugated nanostructure and the richness of amino and hydroxyl groups make them a powerful delivery platform for flumorph(a fungicide)with a high loading efficiency of 47.18%.Meanwhile,the heat converted from the light can accelerate the release of flumorph from CDs,and thus efficiently kill fungus.

Simultaneous acceleration of sulfur reduction and oxidation on bifunctional electrocatalytic electrodes for quasi-solid-state Zn–S batteries

The incomplete sulfur reduction and high ZnS re-oxidation energy barrier along with severe side reactions during the battery cycling compromise the practical application of Zn–S electrochemistry. Herein, a bifunctional electrocatalytic sulfur matrix that simultaneously accelerates the sulfur reduction and ZnS oxidation is proposed to realize a highly-efficient Zn–S cell. It is revealed that the N-heteroatom hotspots are more favorable for facilitating the conversion of S to ZnS while the CoO nanocrystal substantially lowers the ZnS activation energy barrier thereby suppressing the formation of disproportionation species(e.g.,SO_(4)^(2-)) and accumulation of inactive ZnS. Accordingly, the Co O anchored on the N-doped carbon-supported sulfur cathode delivers a high Zn^(2+)storage capacity of 1,172 m Ahg^(-1)and outstanding cycling stability with a capacity retention of 71.6% after500 cycles with a high average Coulombic efficiency of 97.8%. Simultaneously, the stable cycling of solid-state Zn–S pouch cells with an energy density of 585 Whkg^(-1)sulfuris also demonstrated. Moreover, the postmortem analysis reveals that the degradation of Zn–S cells is mainly attributed to the limited reversibility of Zn anodes rather than the ZnS decomposition and/or accumulation. The approach to the bidirectional catalysis manipulated the sulfur redox provides a new perspective to realize the theoretical potentials of Zn–S cells.