Uncontrolled growth of lithium dendrites and huge volume change during the lithium plating/stripping process as well as poor mechanical properties of the solid electrolyte interphase (SEI) are key obstacles to the development of a stable Li metal anode. Here, an ultralight MgN-modified carbon foam (CF-MgN) was fabricated as a collector to address these issues. The calculated results show that the CF-MgN composite is relatively stable in terms of energy.
View Article and Find Full Text PDFThe Co/N-doped carbon material, as an important electrocatalytic material, has been attracted intense interest in ORR and Zn-air battery. Here, we report an efficient Co@N-doped carbon catalyst (Co@N-C-1) obtained by pyrolysis of ZIF precursor with 2-aminobenzimidazole. The introduction of 2-aminobenzimidazole results in the formation of hierarchical meso/microporous structure of the as-prepared Co@N-C-1, effectively avoiding the aggregation of Co nanoparticles during pyrolysis and the higher N content, which contributes to enhance the ORR electrocatalytic activities.
View Article and Find Full Text PDFIn the presence of a quinone, Brønsted acid-catalyzed intramolecular C-N bond formation of o-vinylanilines by electrophilic cyclization was developed, giving the corresponding N-arylindoles in good to high yields. The reaction worked well for o-vinylanilines with terminal and internal C=C double bonds.
View Article and Find Full Text PDFThe N-heterocyclic carbene-catalyzed cascade reaction of enals with malonates to give bicyclic δ-lactones was developed. The cyclopentane- and cyclohexane-fused δ-lactones with three continued stereocenters were obtained in high yields with excellent diastereo- and high enantioselectivities.
View Article and Find Full Text PDFThe N-heterocyclic carbene-catalyzed [3+3] cyclocondensation of bromoenals and aldimines was developed to give the corresponding dihydropyridinones in good yields with excellent enantioselectivities.
View Article and Find Full Text PDFThe chiral N-heterocyclic carbene-catalyzed [4 + 2] cyclization of α-chloroaldehydes and arylidene indanediones was developed, giving the corresponding indenopyrones in good yields with high diastereoselectivities and enantioselectivities.
View Article and Find Full Text PDFThe N-heterocyclic carbene-catalyzed Staudinger reaction of ketenes with isatin-derived ketimines was investigated. The bifunctional NHCs with a free hydroxyl group were demonstrated as efficient catalysts for the reaction, giving the corresponding spirocyclic oxindolo-β-lactams in high yields with excellent diastereo- and enantioselectivities.
View Article and Find Full Text PDFHighly optically pure multisubstituted dihydropyrano[2,3-c]pyrazol-6-(1H)-ones were synthesized via the N-heterocyclic carbene-catalyzed enantioselective [4 + 2] annulation of α-chloroaldehydes and pyrazolone-derived oxodienes.
View Article and Find Full Text PDFIn this study, chemical compositions of fatty oils and bioactivity of crude extracts from Holotrichia diomphalia larvae as Chinese materia medica were investigated for the first time. The chemical compositions of the fatty oils were obtained by two different methods and determined by GC/MS. In total, the petroleum ether extract produced 21 compounds (96.
View Article and Find Full Text PDFZhongguo Zhong Yao Za Zhi
August 2006
Objective: To provide the basis for establishing evaluation criterion, selecting good strains and carring out good agricultural practice of the crude drug.
Method: Representative 22 varieties of Carthamus tinctorius were selected and cultivated in different ecological localities and different years. And the content of safflor yellow A in their corollas were measured by RP-HPLC to compare the differences and their genetic stabilities among varieties.
Zhongguo Ying Yong Sheng Li Xue Za Zhi
May 2004
Aim: To investigate the preventive effects of Panax notoginseng saponins (PNS) and Ginkgo biloba extracts (GbE) on acute oxygen toxicity and the possible mechanisms.
Methods: Mice were injected intraperitoneally with PNS and GbE for 5 days, then were exposed to 500 kPa hyperbaric oxygen (HBO) for 60 min, the convulsion latency, times and interval were observed. Moreover, reactive oxygen (RO) unit, MDA, NO, GSH levels and GSH-Px, CAT, MAO activities of mice brain were determined after they were exposed to HBO for 15 min.