Acidity and Structure of Isosaccharinate in Aqueous Solution: A Nuclear Magnetic Resonance Study

Dilute aqueous solutions of the calcium and sodium salts of -d-isosaccharinate (ISA) have been analyzed by ¹³C and ¹H NMR spectroscopy. The positions of the six ¹³C ISA NMR lines show a pH dependence that can be used to infer that the most acidic proton is the one associated with the carboxylate group, with an aver- age log k⁰ of –3.27 for the reaction H(ISA) H⁺ + ISA^– in solutions made with the sodium salt. In acidic solutions (pH < 4),=" nmr=" signals=" were=" found=" that=" could=" be=" assigned=" to=">-d-isosaccharinate-1,4-lactone (ISL), formed from the dehydration of H(ISA). The pH dependence of the H(ISA) ¹³C line positions, furthermore, reveals that the deprotonated H(ISA) at neutral to high pH assumes a conformation with the carboxylate anion hydrogen-bonded to the secondary alcohol and the cation (Na⁺ or Ca²⁺) interacting with the tertiary alcohol.     

Rod-like Cu/La/O nanoparticles as a catalyst for phenol hydroxylation

Rod-like La/Cu/O nanoparticles, synthesized by a simple coprecipitation reaction with a sonication process, are found to be highly active as a catalyst for the hydroxylation of phenol. Compared to the 4-6 h, 40% yield reported in the literature, our nanoparticle catalyst demonstrates a nearly 100% conversion within 4 h based on gas chromatography.     

Facile synthesis of Au@PNIPAM‐b‐PPy nanocomposites with thermosensitive and photothermal effects

In this article, we reported a facile method to in‐situ synthesize Au@PNIPAM‐b‐PPy nanocomposites with thermosensitive and photothermal effects using amphiphilic poly(N‐isopropylacrylamide)‐block‐poly(pyrrolylmethylstyrene) (PNIPAM‐b‐PPMS) diblock copolymers as ligands. The hydrophobic PPMS block can in‐situ reduce to zero‐valent gold and simultaneously be oxidatively copolymerized with the free pyrrole monomers to form a crosslinked and conjugated polypyrrole (PPy) layer. The hydrophilic PNIPAM block as a stabilizer can produce highly thermosensitive effect. Moreover, the resultant Au@PNIPAM‐b‐PPy nanomaterials show a strong absorption in the near infrared (NIR) region, which endowed the system excellent photothermal effect. On the basis of the PPy photothermal and PNIPAM thermosensitive effects, the above Au@PNIPAM‐b‐PPy nanomaterials show a reversible, soluble‐precipitate transition upon the NIR irradiation off‐on. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3079–3085     

A Free‐Blockage Controlled Release System Based on the Hydrophobic/Hydrophilic Conversion of Mesoporous Silica Nanopores

A pH‐responsive free‐blockage release system was achieved through controlling the hydrophobic/hydrophilic conversion of mesoporous silica nanopores. This system further presented pulsatile release with changing pH values between 4.0 and 7.0 for several cycles. This free‐blockage release system could also release antitumor agents to induce cell death after infecting tumor cells and could have the ability of continuous infection to tumor cells with high drug‐delivery efficiency and few side effects.     

Rh(II)-Cp-TsDPEN catalyzed aqueous asymmetric transfer hydrogenation of chromenones into saturated alcohol: CC and CO reduction in one step

As an efficient catalyst for asymmetric transfer hydrogenation reaction (ATH reaction) of α,β-unsaturated ketones, Rh-Cp^∗-TsDPEN (Cp^∗ = 1,2,3,4,5-pentamethylcyclopenta-1,3-diene, TsDPEN = N-(p-toluenesulfonyl)-1,2-diphenyl- ethylenediamine) shows high chemoselectivity on CO and CC reduction. In our method, both CO and CC bonds in a variety of chromenone derivatives were reduced efficiently in aqueous media, resulting in at least 98% ee and up to 99% yields in a convenient way without further purification. The product was a useful intermediate for deriving chiral chroman-4-amine, which was reported as an effective agent against hypotension and inflammatory pain by inhibiting human bradykinin B1 receptor.     

碳酸铯存在下铁催化立体选择性合成(Z)-2-亚基-1,4-苯并二噁烷衍生物

通过Sonogashira偶联反应合成了邻炔丙基醚苯酚衍生物,在Cs2CO3存在和FeCl3的催化下,进而发生分子内环化反应,立体选择性地合成了一系列(Z)-2-亚基-1,4-苯并二噁烷衍生物.产物的结构通过了1H NMR,13C NMR和HRMS等表征.     

Oil-water interfacial self-assembly: a novel strategy for nanofilm and nanodevice fabrication

How to integrate individual nanostructures into macroscopic thin films has become one of the most intriguing fields in nanoscience and nanotechnology due to the unique properties and important applications of these functional films. Since being discovered in 2004, oil-water interfacial self-assembly of nanostructures has become a novel strategy for fabrication of nanofilms. It is a powerful bottom-up approach for film fabrication due to the low cost and high efficiency, and is simple and universal for almost all low-dimensional nanostructures. In this article, we provide a critical review of the state-of-the-art research activities in this burgeoning self-assembly strategy. We first discuss the thermodynamic mechanism of the oil-water interfacial self-assembly, then the self-assembly of various low-dimensional nanostructures including nanoparticles, one-dimensional (1D) nanostructures, two-dimensional (2D) nanostructures at an oil-water interface developed so far to fabricate high-quality nanofilms. Finally, we present some progress on the construction of functional nanofilm-based nanodevices from this novel strategy based on our research. We conclude this review with critical comments on advantages and the experimental challenges, and further propose the future research and development of this self-assembly strategy for nanodevice construction (105 references).