In addition, a few semiautomated platforms based on high-performance liquid chromatography (HPLC)-assisted automated synthesis 15, fluorous-tag-assisted automated solution-phase synthesis 16 and automated electrochemical solution-phase assembly 17 have also been established, but their synthetic applications are limited and the size of the constructed glycans does not exceed that of hexasaccharide. Although automated enzyme-mediated glycan synthesis has been reported 13, 14, the enzymatic protocol is restricted by the source of enzymes and the scope of carbohydrate substrates. Although automated solid-phase chemical synthesis 8, 9 has been developed to assemble diverse glycans 10, this protocol requires an excess amount of building blocks at each coupling step 11, the synthesis cannot be scaled up and usually the reaction cannot be directly monitored 12, thus limiting its application to some extent. The development of synthetic technology has enabled automated synthesis, ranging from small pharmaceutical molecules to macromolecules such as nucleic acids or proteins 5, 6, 7. It usually involves multistep manual operations and requires a highly skilled workforce, making it time-consuming and laborious 2, 3, 4. However, due to the intrinsic complexity of carbohydrate structures, furnishing pure and structurally well-defined glycans to study their functions is a formidable task. Furthermore, automated ten-component tandem reactions were performed, allowing the assembly of arabinans up to a 1,080-mer using this automated multiplicative synthesis strategy.Ĭarbohydrates are ubiquitous in nature, and play significant roles in almost all life processes, such as cell–cell communication, cell growth and proliferation, pathogen–host interaction, and immunoresponse 1. The automated synthesis of a fully protected fondaparinux pentasaccharide (an anticoagulant) was realized on the gram scale. Using this synthesizer, a library of oligosaccharides covering various glycoforms and glycosidic linkages was assembled rapidly, either in a general promoter-activation mode or in a light-induced-activation mode. This was achieved by making a dual-mode automated solution-phase glycan synthesizer. Here we report an automated solution-phase multiplicative synthesis of complex glycans enabled by preactivation-based, multicomponent, one-pot glycosylation and continuous multiplying amplification. However, the synthesis of structurally well-defined carbohydrates, especially large-sized glycans, is a challenging task. We discover that the Fe–Co dual sites embedded in N-doped porous carbon are beneficial for the activation of oxygen by weakening the O O bonds.Carbohydrates play essential roles in nature, such as in cell–cell communication, cell growth and immunoresponse. In addition, the power density and the specific energy density reach 260 mW cm −2 and 870 W h kg Zn −1. Furthermore, when employed as a cathode catalyst in a Zn–air battery, the (Fe,Co)/CNT exhibits high voltages of 1.31 V and 1.23 V at discharge current densities of 20 mA cm −2 and 50 mA cm −2, respectively. The ORR test reveals that the performance of the (Fe,Co)/CNT is superior to most of the reported non-precious catalysts in alkaline electrolytes. 0.842 V), outperforming those of the commercial Pt/C. The electrocatalyst shows state-of-the-art ORR performance with an admirable onset potential ( E onset, 1.15 V vs. Herein, we construct a novel electrocatalyst with Fe–Co dual sites embedded in N-doped carbon nanotubes ((Fe,Co)/CNT), which exhibits inimitable advantages towards the oxygen reduction reaction.
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