Scalable total synthesis of horsfiequinone A

Starting from two commercially available substrates, methoxyhydroquinone and piperonyl alcohol, a scalable four-step total synthesis of horsfiequinone A was developed. The notable feature of the synthesis is the application of two continuous sequential transformations. Namely, the key aldehyde 9 and horsfiequinone A were prepared via scalable Wittig/hydrolysis and Wittig/catalytic hydrogenation/oxidation sequences, respectively. Importantly, the synthetic route required only three recrystallizations and one column chromatography purification step.     

Environment-friendly bio-materials based on cotton-carbon aerogel for strontium removal from aqueous solution

Cotton carbon aerogel was prepared and used as a new water-insoluble adsorbent to remove strontium from aqueous solution. A comprehensive study on adsorption of strontium by cotton carbon aerogel was conducted regarding the effects of initial pH, temperature, initial strontium concentration, and contact time. The adsorbent was characterized by SEM. The results of regression analysis indicated that the adsorption process largely depends on the pH and temperature. The optimum pH range for adsorption process is 5–7. The maximum removal efficiency of strontium from aqueous solution was 60.16%. Moreover, cotton carbon aerogel adsorbent has good reusability before the fifth reuse.     

An Aluminum–Sulfur Battery with a Fast Kinetic Response

The electrochemical performance of the aluminum‐sulfur (Al‐S) battery has very poor reversibility and a low charge/discharge current density owing to slow kinetic processes determined by an inevitable dissociation reaction from Al₂Cl₇^? to free Al³⁺. Al₂Cl₆Br^? was used instead of Al₂Cl₇^? as the dissociation reaction reagent. A 15‐fold faster reaction rate of Al₂Cl₆Br^? dissociation than that of Al₂Cl₇^? was confirmed by density function theory calculations and the Arrhenius equation. This accelerated dissociation reaction was experimentally verified by the increase of exchange current density during Al electro‐deposition. Using Al₂Cl₆Br^? instead of Al₂Cl₇^?, a kinetically accelerated Al‐S battery has a sulfur utilization of more than 80 %, with at least four times the sulfur content and five times the current density than that of previous work.     

Iron Nanoparticles Protected by Chainmail-structured Graphene for Durable Electrocatalytic Nitrate Reduction to Nitrogen

The electrochemical nitrate reduction reaction (NO₃RR) is an appealing technology for regulating the nitrogen cycle. Metallic iron is one of the well-known electrocatalysts for NO₃RR, but it suffers from poor durability due to leaching and oxidation of iron during the electrocatalytic process. In this work, a graphene-nanochainmail-protected iron nanoparticle (Fe@Gnc) electrocatalyst is reported. It displays superior nitrate removal efficiency and high nitrogen selectivity. Notably, the catalyst delivers exceptional stability and durability, with the nitrate removal rate and nitrogen selectivity remained ≈96 % of that of the first time after up to 40 cycles (24 h for one cycle). As expected, the conductive graphene nanochainmail provides robust protection for the internal iron active sites, allowing Fe@Gnc to maintain its long-lasting electrochemical nitrate catalytic activity. This research proposes a workable solution for the scientific challenge of poor lasting ability of iron-based electrocatalysts in large-scale industrialization.     

Formation of CeO2-ZrO2 solid solution nanocages with controllable structures via Kirkendall effect

Nanocages with controllable shapes, tunable compositions, and narrow size distributions have been synthesized by using the monodispersed ceria clusters as templates.     

Synthetic Studies on Camptothecins. Part 1

A six‐step asymmetric total synthesis of (20S)‐camptothecin ( 1 ) has been accomplished in 25% overall yield starting from the known pyridone 3 . The key steps in this synthesis are the chemoselective Ni‐catalyzed hydrogenation of 3‐cyanopyridone 6 to 3‐formylpyridone 7 in AcOH/pyridine/H₂O and the Davis asymmetric hydroxylation of tricyclic lactone 4 utilizing a chiral N‐sulfonyloxaziridine into (4′S)‐tricyclic hydroxylactone 2 .     

Using Congo red to report intracellular hydrogelation resulted from self-assembly of small molecules

This communication reports the use of Congo red to stain the nanofibers of self-assembled small molecules for assaying intracellular supramolecular hydrogels, which provides a convenient method to explore molecular self-assembly inside cells.     

Unsymmetric bimetal(II) complexes: Synthesis, structures and catalytic behaviors toward ethylene

A series of unsymmetric bimetal(II) (Fe, Co and Ni) complexes ligated by 2-methyl-2,4-bis(6-iminopyridin-2-yl)-1H-1,5-benzodiazepines were synthesized and characterized by IR spectra and elemental analysis, while a representative nickel(II) complex (5a) was determined by single-crystal X-ray crystallography. These iron(II) complexes were found to exhibit good activities for ethylene oligomerization and polymerization in the presence of MMAO and afforded α-olefins in high selectivity, and the composition of oligomers followed the Schluz-Flory distribution. The nickel(II) complexes mainly dimerize ethylene with considerable activity. The influences of coordinative ligands and reaction parameters were fully investigated on the catalytic activity and properties of these complexes.     

Incomplete Semiiterative Methods for Solving Operator Equations in Banach Space

There are several methods for solving operator equations in a Banach space. The successive approximation methods require the spectral radius of the iterative operator be less that 1 for convergence. In this paper, we try to use the incomplete semiiterative methods to solve a linear operator equation in Banach space. Usually the special semiiterative methods are convergent even when the spectral radius of the iterative operator of an operator of an operator equation is greater than 1.