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The transient dark activation of opsin by 11-cis-13-desmethylretinal and its dihydro analogue was studied to determine the mechanism of dark activity of the 13-desmethylretinal/rod opsin complex. Three binding domains comprise the opsin cavity incorporating the retinals, namely, site I for the cyclohexene, site II for the polyene chain, and site III for protonated Schiff base (PSB). The cyclohexene moiety occupies site I as required for opsin activation, while 11-cis-retinals activate the protein during the binding process prior to pigment formation. The protein is inactivated by protonation of the Schiff base. The polyene chain then assumes a shape that results in a transient Meta-II-like conformation in opsin.

The metal-nitrogen-carbon (M-N-C)-based catalysts are promising to replace PGM (platinum group metal) to accelerate oxygen reduction reaction due to their excellent electrocatalytic performance. However, the inferior intrinsic activity and poor active site density confining further improvement in their performance. Modulating the electronic structure and reasonably designing the pore structure are widely acknowledged effective strategies to boost the activity of the M-N-C catalysts. However, it is a great challenge to form abundant pores to regulate the electronic structure via the facile method. Herein, a hierarchical, porous dual-atom catalyst FeNi-NPC-1000 has been architectured by the Na 2 CO 3 template method and bimetallic doping modification strategy. Benefitting from the optimized pore and electronic structure, the as-prepared FeNi-NPC-1000 possesses a high specific surface area (1412.8 m 2 g -1 ) and improved ORR activity ( E 1/2 = 0.877 V vs RHE), which is superior to that of Pt/C ( E 1/2 = 0.867 V vs RHE). With the evidence of AC-STEM, XAS, and DFT, the FeNi-N 8 -C moiety is proven to be the key active site to realize high-efficiency ORR catalysis. When assembled it as an air cathode of ZABs, FeNi-NPC-1000 displays superior discharge performance ( P max = 367.1 mW cm -2 ) and a stable battery long-life. This article will provide a new strategy for designing dual-metal atomic catalysts applied in metal-air batteries.

Challenges remain to show good capacitive performance while achieving high loadings of active materials for supercapacitors. Trying to realize this version, a nickel-protecting carbon fiber paper@Co-doped NiS x (Ni-CP@Co-NiS x ) electrode with high specific gravimetric, areal, and volumetric capacitance is reported in this work. This free-standing electrode is prepared by an electroplating-hydrothermal-electroplating (EHE) three-step method to achieve a high loading of almost 26.7 mg cm -2 . The cobalt-doping and nickel-protection strategies effectively decrease the impedance and inhibit the active material dropping from the electrode resulting from the expansion stress, which endows the Ni-CP@Co-NiS x electrode with a high rate and good cycling performance, especially with an ultrahigh specific areal/volumetric/gravimetric capacitance of 53.3 F cm -2 /2807 F cm -3 /1997 F g -1 at 5 mA cm -2 , respectively. Employing activated carbon functionalized with riboflavin (AC/VB2) as a negative electrode, the asymmetric supercapacitor device delivers a very high energy density of up to 60.4 W h kg -1 . This work demonstrates that electrodes with a high loading density and excellent performance can be obtained by the combination of the EHE method to adjust the internal conductivity and external structural stability.

Highly stereoselective construction of 1,2- cis -Ara p linkages has been achieved, which featured a broad range of alcoholic acceptors, including strong nucleophiles and complex bioactive molecules. This method was applied to a regioselective and orthogonal one-pot synthesis of a pentasaccharide, which was the structural motif of a side chain in type II arabinogalactan.

Described here is a selective synthesis of 2,3-dihydropyrrole-fused N -glycosides through rhodium-catalyzed denitrogenative transannulation of N -sulfonyl-1,2,3-triazoles with glycals. A series of pyrroline-fused N -glycosides are afforded in moderate to excellent yields with exclusive regioselectivity and stereoselectivity. Functional application of such a resultant product by oxidative addition and epoxidation is also explored. Notably, the treatment of a pyrroline-fused N -glycoside ( 3a ) with TMSOTf efficiently leads to an interesting unexpected C -nucleoside ( 9 ) via a TMSOTf-inducing ring opening/acetyl migration/ring closing reaction sequence.

A H 2 /CO 2 fuel cell is a promising device that can convert CO 2 into hydrocarbon fuel with electricity generation. Herein, a facile electrospinning method has been used to synthesize the embedded Ru-CNF catalyst in which Ru nanoparticles are dispersed homogeneously within N-doped carbon nanofibers. This catalyst exhibits a high CH 4 production rate of 308.46 μmol g cat -1 h -1 at 170 °C, which is superior to that of the Ru/CNF (242.53 μmol g cat -1 h -1 ) and Ru/CNT (194.24 μmol g cat -1 h -1 ). The enhanced CO 2 RR performance of Ru-CNF is ascribed to the well-distributed Ru nanoparticles within the CNF matrix and synergistic effect of Ru sites with N species, which results in forming the increased CO 2 RR active sites, hence improving the catalytic activity. Simultaneously, it can achieve a peak power density of 1.8 W m -2 on the strength of anodic (H 2 oxidation) and cathodic (CO 2 reduction and H 2 evolution) reactions with remarkable stability. Such findings give a theoretical basis of CO 2 RR in the H 2 /CO 2 fuel cell system, which could hold great value to further develop the high-efficiency catalysts for CO 2 reduction.

The shape control of platinum nanocrystals is significant to the enhancement of their catalytic performance in terms of activity and selectivity. However, it still remains a major challenge to prepare Pt nanocrystals with tunable shape and clean surface in an eco-friendly way. This article develops a facile and green strategy to prepare well tuned platinum nanocrystals employing poly(diallyldimethylammonium chloride) (PDDA) as the capping agent, reductant, and stabilizer simultaneously in a facile hydrothermal process. It is identified that the variation of PDDA concentration is crucial to control the growth of crystalline facets, leading to the formation of cubic, truncated cubic, and octahedral Pt nanocrystals with sizes tunable from ca. 17 nm to ca. 50 nm. The resultant Pt nanocrystals exhibit excellent electrocatalytic activity and stability toward the oxygen reduction reaction (ORR) in acidic media compared with those of commercial Pt black and the state-of-the-art Pt/C catalyst. It is proposed that the preferential Pt surface and the decoration of PDDA, which modulates the electronic structures and electrooxidation of Pt nanocrystals, synergistically contribute to the enhanced catalytic performance.