Approach for the Direct Synthesis of β-Dichlorosubstituted Acetanilides Using Iodine Trichloride (ICl3) as the Oxidant and Catalyst

A reliable method for direct synthesis of β‐dichlorosubstituted acetanilides is reported. The key transformation involves the oxidative and catalytic cleavage of a carbon‐carbon bond in the presence of iodine trichloride (ICl₃). In this protocol ICl₃ is used not only as the catalyst but also as the oxidant which widely broadens the scope of its application in organic synthetic chemistry.     

Ferroelectric liquid crystals with axially chiral 2,2′-spirobiindan-1,1′-dione cores

The axially chiral mesogens 5-alkoxy-5′-[(4-alkoxybenzoyl)oxy]-2,2′-spirobiindan-1,1′-dione (QL7-n) were synthesised as racemic mixtures and resolved as single enantiomers by preparative chiral phase HPLC. The shorter homologues (R)-QL7-8 and QL7-9 form enantiotropic N* and SmC* phases, whereas the longer homologues (R)-QL7-10 and QL7-12 form an enantiotropic SmC* phase only. Texture analysis showed that the helical pitch of the N* phase is below the wavelength range of visible light; a helical pitch of 187 nm was measured at T – T_NI = –5 K by selective reflection using enantiomerically enriched mixtures of (R)- and (S)-QL7-8 (0.35 ≤ ee ≤ 0.80). Spontaneous polarisations were measured as a function of temperature in the SmC* phase by the triangular wave method. P_S values at saturation range from 102 nC cm^–2 for (R)-QL7-8 to 120 nC cm^?2 for (R)-QL7-9, which are up to three times greater than the highest polarisation previously reported for an axially chiral SmC* mesogen. Optical tilt angles θ were measured as a function of temperature and showed a sharp rise consistent with first-order N*–SmC* or I–SmC* transitions, with values at saturation ranging from 42 to 44°.     

Ag/CNT‐catalyzed hydroamination of activated alkynes with aromatic amines

As a nanoparticle support material, carbon nanotubes (CNTs) provide a certain potential activation of catalysis in heterogeneous catalytic organic reactions. Herein, an efficient Ag/CNT‐catalyzed synthesis of enamines via hydroamination of activated alkynes with aromatic amines has been described. This catalyst still retains catalytic activity after being recycled and reused three times. In addition, it represents a green and environmentally friendly process for preparation of enamines. Copyright © 2013 John Wiley & Sons, Ltd.     

国家科技重大专项课题绩效管理与绩效评价指标体系初探

国家科技重大专项是为实现国家目标,通过核心技术突破和资源集成,在一定时限内完成的重大战略产品、关键共性技术和重大工程。本文在梳理国家科技重大专项绩效管理现状的基础上,提出了适用于国家科技重大专项绩效管理的评价方法,构建了国家科技重大专项绩效评价指标体系,结论可为国家科技重大专项课题成果的比较分析提供平台。     

Reliability of flexible electrically conductive adhesives

Based on our previous work about electrically conductive adhesives (ECAs), a flexibilizer named 1,3‐propanediol bis (4‐aminobenzoate) was used to fabricate flexible ECAs (FECAs). ECAs, FECAs, and electronic devices connected by them were carried out the hot and humid aging test under constant humidity level of 85% relative humidity at 85 °C for 600 h. After aging, the bulk resistance change of ECAs was about 26%, that of FECAs was a little higher, about 29%. The contact resistance change of devices connected by ECAs and FECAs was very great, about 450% and 410%, respectively. The bonding area at connection interface between colloids and devices had delamination, even cracks. The delamination of ECAs was calculated about 60%, the average shear strength of ECAs was reduced about 45%, and those of FECAs were about 50% and 30%, respectively, so FECAs had a higher bonding stability in hot and humid environment. Copyright © 2012 John Wiley & Sons, Ltd.     

Nonlinear optical metal-organic frameworks for ratiometric temperature sensing in physiological range

The precise and real-time sensing of the temperature within the physiological range is of great significance in biology and medicine. Here, a Zn-based metal-organic framework (MOF) named Zn-TCOMA is synthesized with good SHG performance due to its unique structure of the ligand and 3D frameworks. By encapsulating the two-photon fluorescent dye DMASE into the pores of Zn-TCOMA, the composite Zn-TCOMA?DMASE is obtained and simultaneously exhibits SHG response and two-photon fluorescence. Utilizing the intensity ratio between two-photon fluorescence of DMASE and SHG signal of Zn-TCOMA, Zn-TCOMA?DMASE exhibits ratiometric temperature sensing property at physiological temperature region of 20～60 °C with high sensitivity. This MOF thermometer also shows excellent repeatability, good biocompatibility, and high temperature resolution of 0.018 °C, opening a new avenue to develop diverse optical thermometric or thermographic applications in biotechnology or other areas.     

Optimal lower eigenvalue estimates for Hodge-Laplacian and applications

We consider the eigenvalue problem for Hodge-Laplacian on a Riemannian manifold M isometrically immersed into another Riemannian manifold $\overline{M}$. We first assume the pull back Weitzenböck operator of $\overline{M}$ bounded from below, and obtain an extrinsic lower bound for the first eigenvalue of Hodge-Laplacian. As applications, we obtain some rigidity results. Second, when the pull back Weitzenböck operator of $\overline{M}$ bounded from both sides, we give a lower bound of the first eigenvalue by the Ricci curvature of M and some extrinsic geometry. As a consequence, we prove a weak Ejiri type theorem, that is, if the Ricci curvature bounded from below pointwisely by a function of the norm square of the mean curvature vector, then M is a homology sphere. In the end, we give an example to show that all the eigenvalue estimates are optimal when $\overline{M}$ is the space form.     

低温/高温复合超导磁体的研究进展

低温/高温复合超导体的研究是当前超导领域比较新的一个课题,文章介绍了低温/高温复合超导体的结构以及加工工艺,并结合相关数值模拟和实验结果对复合超导体电流分布、热传导性质、理论机理和稳定性研究等相关问题进行了讨论与探索。     

Asymmetric Michael Addition of Aldimino Esters with Chalcones Catalyzed by Silver/Xing‐Phos: Mechanism‐Oriented Divergent Synthesis of Chiral Pyrrolines

The mechanism‐oriented reaction design for the divergent synthesis of chiral molecules from simple starting materials is highly desirable. In this work, aromatic amide‐derived nonbiarylatropisomer/silver (silver/Xing‐Phos) complex was used to catalyze the Michael addition of glycine aldimino esters to chalcones and successfully applied to the subsequent cyclocondensation to afford substituted cis‐Δ(1)‐pyrroline derivatives with up to 98 % ee. Besides the inherent performance of the chiral Ag/Xing‐Phos catalyst system, it was found that the workup of such reactions played an important role for the stereoselective construction of stereodivergent Δ(1)‐pyrrolines, in which an epimerization of the cis‐Δ(1)‐pyrrolines to the trans‐isomers during was revealed.