Latest ArticlesAntimony-based materials have become promising anodes within lithium-ion batteries (LIBs) due to their low cost and the high theoretical capacity. However, there is a potential to further enhance the electrochemical performance of such antimony-based materials. Herein, Sb2Se3@C nanofibers (Sb2Se3@CNFs) are designed and obtained via a novel electrospinning method. Upon electrochemically testing as an anode within LIBs, the Sb2Se3@CNFs (annealed at 600 ℃) delivers a remarkably good cycling performance of 625 mAh/g at 100 mA/g after 100 cycles. Moreover, it still remains at 490 mAh/g after 500 cycles with an applied current density of 1.0 A/g. The excellent performance of the Sb2Se3@CNFs can be attributed to the fact that the N-doped C matrices not only remit the volume expansion of materials, but also enhance the electrical and ionic conductivity thusly increasing the lithium-ion diffusion. The obtained Sb2Se3@CNFs are promising anode for LIBs in the future.
β-Elemene is a volatile oil used for the treatment of cancer, but poor solubility, low bioavailability, and various adverse reactions limit its application. For ameliorating risks of the venous toxicity of β-elemene, intravenously injectable micelle of β-elemene was prepared using the thin-film hydration method. The results pointed out the micelles were uniformly spherical with about 20.96 ± 0.1966 nm in average diameter and exhibited high entrapment efficiency (99.02% ± 0.88%). As revealed by drug release studies in vitro, β-elemene micelles had sustained drug release. Compared with free β-elemene, the micelles increased the drug cellular uptake and enhanced the anti-tumor effect in vitro through retarding cell cycle and inducing apoptosis. Meanwhile, the elevated serum stability of β-elemene micelles implied less drug leakage and reduced toxicity. The wound healing and tube formation assay in vitro demonstrated the anti-metastasis and anti-angiogenesis effects of β-elemene micelles. Moreover, the pharmacokinetics study showed the AUC and T1/2 of β-elemene in micelle group were 1.79 and 1.62 times of that in free β-elemene group, suggesting the circulation time of β-elemene in the blood had been prolonged. In addition, β-elemene micelles showed a favorable antitumor response compared with the β-elemene solution on C26 colon cancer-bearing mice model. Local irritation study investigated in rabbits indicated that the β-elemene micelles strikingly mitigated the irritation to the injection sites compared with free β-elemene. These results proved that the micelle could be a good candidate as an auspicious drug delivery system of β-elemene for the prospective clinical treatment of carcinoma.
The synthesis of α-ZrP with a range of crystallinity is of high importance due to the different requirements in various applications. Nanosized crystalline α-ZrP is typically obtained by refluxing amorphous ZrP in concentrated H3PO4 solutions. Microcrystalline α-ZrP are obtained by direct precipitation in the presence of either HF or oxalic acid which are used as complexing agents for zirconium. These larger crystals are useful as ion-exchangers in column-type applications as the back pressure can be significantly reduced. A novel minimalistic synthesis that is green, simple and fast is highlighted in this review. Both nano-sized and micro-sized α-ZrP can be prepared via this protocol to meet many potential applications. Applications of α-ZrP in ion-exchange, catalysis, lubricants, intercalation hosts, polymer fillers and fire retardants are discussed.
Enantiomerically pure 2-substituted indolines are an important class of nitrogen heterocycles that occur frequently in many alkaloid natural products and biologically active compounds. Consequently, the synthesis of such skeletons is of great significance. The past years have witnessed a number of remarkable advances in the development of efficient strategies to construct this class of chiral compounds. This review summarizes the recent advances in asymmetric synthesis of 2-substituted indoline derivatives. Due to the limitation of the length, this review only summarizes those works published from January of 2012 to January of 2019. Meanwhile, methods towards synthesis of fused and spirocyclic indolines will not be discussed in this review.
An enantioselective carboxylative cyclization of propargylic alcohols and CO2 was realized under mild conditions, based on a kinetic resolution strategy, which enabled the synthesis of chiral cyclic carbonates and propargylic alcohols with promising yield and enantioselectivity simultaneously.
A divergent intramolecular reaction of phosphine tethered alkyne in protic solvent was developed. This provided a novel and simple access to a large variety of (Z)-alkenylphosphine oxides and phospholane oxides. Our preliminary studies suggested that these divergent reactions are closely related to the reaction condition and molecular structure. A possible mechanism of C-P bond cleavage of a pentacoordinated hydroxyphosphorane intermediate was proposed.
The acetyl ester plays an important role for protection of the hydroxyl groups in carbohydrates synthesis. In the present study, we described an efficient deprotection of acetyl group of pentacyclic triterpenoid by using methanolic ammonia in THF solution. Good selectivity for cleaving gal-C2-OAc group of 3β-hydroxy-olean-12-en-28-oic acid 28-N-2, 3, 4, 6-tetra-O-acetyl-β-D-galactopyranoside (3) was achieved in the presence of methanolic ammonia within 4 h at low temperature (-60℃) in a yield of 56%. The reaction disclosed here provides a new method for the synthesis of C2 selective modified carbohydrates, which is more useful than conventional synthesis procedure that usually requires many steps including temporary regioselective protection and deprotection. When the reaction temperature was increased from -60℃ to room temperature, the cleavage of the other three acetyl groups of galactose in an order of C4-OAc > C3-OAc > C6-OAc was observed. Based on this study, a plausible route for the deacetylation reaction has been proposed.
A new method for the synthesis of 3-thioazaspiro[4,5]trienones was developed using Pd nanoparticle catalysts, which are highly efficient, environmentally friendly and recyclable. Alkynes and thiophene phenols are effectively cyclized by Pd/ZrO2 catalyst under visible light irradiation. The present protocol simply utilizes visible light as the safe and ecofriendly energy source, and the Pd/ZrO2 nanocomposite as photocatalyst provides a simple and practical approach to various 3-thioazaspiro[4,5]trienones in moderate conditions to high yields
Organocatalysis represents a promising field in chemical fixation of CO2. Herein, a facile metal-free strategy was reported for the one-pot preparation of cyclic carbonates and α-hydroxy ketones from vicinal diols, propargylic alcohols and CO2. Wide scope of vicinal diols and propargylic alcohols was demonstrated to be efficient under the DBU-catalyzed conditions. A plausible mechanism was proposed, which included detailed main and side reactions under the metal-free conditions.
In this study, various nonionic surfactants (NS) with different ethylene oxide (EO) numbers and tail lengths and its binary blends with anionic surfactants (AS) were used as emulsifiers for naphthenic oil to form the microemulsion metalworking fluids (MWFs), and the effects of them on the stability of the emulsion system were investigated by formulation triangle method. The results indicated that binary complex surfactants of NS and AS as emulsifiers exhibited better emulsifying effect than that of single NS. NS with different EO numbers and tail lengths presented various emulsifying effects. NS (EO = 10) exhibited the greatest number of stable formulations, especially the TX-10, but no linear relationship existed between the number of stable formulations and the tail length of NS. In addition, aromatic primary alcohol ethoxylate (APAE) series surfactants containing benzene groups similar to the cycloalkanes in the naphthenic oil so that presented the best emulsifying affect and the greatest number of stable formulations. The co-surfactant of sodium dodecyl benzene sulfonate (SDBS) binary blends with NS exerted the best synergistic effect, and the stable formulations numbers were ranged from 5 to 7, next sodium stearate (SS) comes last followed by sodium dodecyl sulfate (SDS-1) and sodium dodecyl sulfonate (SDS-2).