New Deoxygenation Method for Amine N-Oxides Using Dimethylthiocarbamoyl Chloride

A facile and efficient deoxygenation method for various amine N-oxides to their corresponding amines is described. The experimental procedure is quite simple and the products are obtained in excellent yields.     

Mild and Efficient Deoxygenation of Amine‐N‐oxides with MoCl5/NaI System

The MoCl₅/NaI system was found to be a new reagent for deoxygenation of various amine‐N‐oxides to the corresponding amines in good to excellent yields under mild conditions.     

Mild and Efficient Deoxygenation of Amine-N-oxides with BiCl3/Indium System

The BiCl₃/indium system was found to be a new reagent for deoxygenation of various amine-N-oxides to the corresponding amines in good to excellent yields under mild conditions.     

Mo(CO)6-promoted facile deoxygenation of α,β-epoxy ketones and α,β-epoxy esters

Deoxygenation of α,β-epoxy ketones and α,β-epoxy esters is accomplished in high yields under mild and neutral conditions by the use of Mo(CO)₆.     

Bis(pertrifluoromethylcatecholato)silane: Extreme Lewis Acidity Broadens the Catalytic Portfolio of Silicon

Given its earth abundance, silicon is ideal for constructing Lewis acids of use in catalysis or materials science. Neutral silanes were limited to moderate Lewis acidity, until halogenated catecholato ligands provoked a significant boost. However, catalytic applications of bis(perhalocatecholato)silanes were suffering from very poor solubility and unknown deactivation pathways. In this work, the novel per(trifluoromethyl)catechol, H₂cat^CF3, and adducts of its silicon complex Si(cat^CF3)₂ ( 1 ) are described. According to the computed fluoride ion affinity, 1 ranks among the strongest neutral Lewis acids currently accessible in the condensed phase. The improved robustness and affinity of 1 enable deoxygenations of aldehydes, ketones, amides, or phosphine oxides, and a carbonyl-olefin metathesis. All those transformations have never been catalyzed by a neutral silane. Attempts to obtain donor-free 1 attest to the extreme Lewis acidity by stabilizing adducts with even the weakest donors, such as benzophenone or hexaethyl disiloxane.     

Formal Aniline Synthesis from Phenols through Deoxygenative N-Centered Radical Substitution

Phenolic, lignin-derived substrates have emerged as desirable biorenewable chemical feedstocks for coupling reactions. A radical-mediated conversion of phenol derivatives to anilines is reported, using unfunctionalized hydroxamic acids as the N-centered radical source. The applicability of this triethyl phosphite mediated O-atom transfer approach, which tolerates a range of steric and electronic demands to naturally occurring phenols and lignin models, has been demonstrated in this work to access the corresponding aniline derivatives.     

Modulating Electrostatic Interactions in Ion Pair Intermediates To Alter Site Selectivity in the C−O Deoxygenation of Sugars

Controlling which products one can access from the predefined biomass‐derived sugars is challenging. Changing from CH₂Cl₂ to the greener alternative toluene alters which C?O bonds in a sugar are cleaved by the tris(pentafluorophenyl)borane/HSiR₃ catalyst system. This increases the diversity of high‐value products that can be obtained through one‐step, high‐yielding, catalytic transformations of the mono‐, di‐, and oligosaccharides. Computational methods helped identify this non‐intuitive outcome in low dielectric solvents to non‐isotropic electrostatic enhancements in the key ion pair intermediates, which influence the reaction coordinate in the reactivity‐/selectivity‐determining step. Molecular‐level models for these effects have far‐reaching consequences in stereoselective ion pair catalysis.     

真空环境中油水分离的试验研究

针对真空环境中油水分离问题,以真空滤油机为研究对象,构建了多参数实时耦合的油水分离试验系统,并利用Labview软件进行了数据的采集和处理。分析了油水分离的主要影响因素,结果表明,在试验参数范围内,水的初始含水率对脱水率的影响较大,真空压力和温度对脱水率呈单调变化的趋势,运行时间存在一个较优值30s。上述结果可为深入研究真空滤油机油水分离机理提供参考。     

Deoxygenative Borylation of Secondary and Tertiary Alcohols

Two different approaches for the deoxygenative radical borylation of secondary and tertiary alcohols are presented. These transformations either proceed through a metal‐free silyl‐radical‐mediated pathway or utilize visible‐light photoredox catalysis. Readily available xanthates or methyl oxalates are used as radical precursors. The reactions show broad substrate scope and high functional‐group tolerance, and are conducted under mild and practical conditions.     

脱氧La0.5Ca0.5MnO3样品的铁磁-反铁磁转变和电阻率变化

研究了氧空位对La_0.5Ca_0.5MnO₃ （LCMO）多晶块材的电输运和磁性质的影响. 随着氧空位的增加, 样品在高温段的电阻率一直增加, 并满足绝热小极化子模型, 而低温段的电阻率先下降后上升, 并出现明显的dR/dT>0的行为, 直至最后变为绝缘的. 氧空位的增加抑止了反铁磁相的出现, 使得脱氧的LCMO样品不发生反铁磁转变, 进一步增加氧空位则会抑制铁磁相. 关键词： 0.5Ca_0.5MnO₃')" href="#">La_0.5Ca_0.5MnO₃ 反铁磁相变 铁磁相变 脱氧