新型Cd-苯并噻二唑类的金属有机骨架中的光诱导脱羧反应

基于相同配体2,1,3-苯并噻二唑-4,7-二羧酸(H2BTDC),通过不同的溶剂热反应,合成了两个新的3D结构的金属有机框架配合物1[Cd_4(BTDC)_4·5H_2O]和2[Cd_2(BTDC)_2(DMF)·1.5H_2O]。在配合物1的结构中存在两个相邻发色团(BTD单元)为反式平行的排列方式,距离为3.987,小于反式二聚物的理论计算值(4 ?)。在相关的紫外可见吸收光谱中观察到,配合物1在470nm处吸收带的能量低于单个BTD单元典型吸收带的能量。这些证据揭示了在配合物1的结构中存在反式苯并噻二唑二聚体。通过研究光照前后配合物1和2的稳态光谱及电子顺磁共振(EPR)光谱发现,这两个配合物中存在光诱导电子转移引起的光致变色效应,并产生了相应的阴离子自由基。相关的FT-IR光谱表明,由于这一自由基的产生,配合物1和2进一步发生了配体单元的脱羧反应,释放出二氧化碳气体(2331cm~(-1)、2361cm~(-1))。     

Efficient synthesis of aryl-substituted carbazoles via tandem double or triple suzuki coupling and cadogan cyclization

An efficient one-step method to prepare aryl-substituted carbazoles via tandem double or triple CC bond formations by multiple Suzuki couplings and CN bond formation by Cadogan cyclization has been developed. The developed method employs commercially available or easily preparable polybromonitrobenzenes and arylboronic acids as starting materials, tolerates various functional groups, and provides good yields.     

Synthesis of crescent shaped heterocycle-fused aromatics via Garratt-Braverman cyclization and their DNA-binding studies

Three crescent shaped heterocycle-fused phenanthrene based systems 1–3 have been synthesized starting from benzene (or substituted benzene) 1,2-bis-propargyl alcohols. Bis-alkylation with propargylic bromides provided the key intermediate, the bis-propargyl bis-ethers. In spite of the possibility of many competing reactions, the latter underwent facile double Garratt-Braverman cyclization to provide compounds 1–3 in near quantitative yield, in a striking reaction involving the formation of four C–C bonds in a single step. Compounds 1–3 showed binding interaction with DNA, predominantly, via groove binding along with partial intercalation (combilexins). Molecular docking study supported the proposed binding modes.     

Potassium bromide catalyzed NS bond formation via oxidative dehydrogenation

N-Substituted benzo[d]isothiazol-3(2H)-ones are a family of compounds with extremely important application. Recently, we have developed a new green pathway to synthesize these compounds via potassium bromide-catalyzed intramolecular oxidative dehydrogenative cyclization. This reaction has high functional group tolerance and affords excellent yield even in gram scale.     

Synthesis of 2-azabicyclo[2.1.0]pentanes by the intramolecular nucleophilic substitution of cyclopropylmagnesium carbenoids with magnesium anilide

A variety of 2-azabicyclo[2.1.0]pentanes were synthesized by the intramolecular nucleophilic substitution of cyclopropylmagnesium carbenoids with magnesium anilide. The 1-chlorocyclopropyl p-tolyl sulfoxides possessing an N-aryl-substituted aminomethyl group were prepared from dichloromethyl p-tolyl sulfoxide, α,β-unsaturated carboxylic acid esters, and anilines in four steps. The deprotonation of the amine with t-BuMgCl followed by sulfoxide/magnesium exchange of the sulfoxides with i-PrMgCl led to the generation of the cyclopropylmagnesium carbenoids possessing a magnesium anilide moiety. Subsequent intramolecular nucleophilic substitution of the cyclopropylmagnesium carbenoids occurred in a 4-exo-tet manner to give the 2-azabicyclo[2.1.0]pentanes. The optically active 2-azabicyclo[2.1.0]pentane was synthesized using a p-tolylsulfinyl group as a chiral auxiliary.     

Polymeric materials for lithium‐ion cells

Lithium‐ion (Li‐ion) cells have gained considerable attention in recent years as a power source for various applications owing to their high voltage, high energy density, low self‐discharge, and excellent cycle life. Polymeric materials play a pivotal role in the processing, performance, and safety of Li‐ion cells. The polymeric materials used in Li‐ion cells include: binder for electrode processing, separator, electrolyte, and electrode active material. Active research is being pursued in all of these areas to improve the energy density, power density, cycle life, and safety of Li‐ion cells. This review article gives an overview of the various polymeric materials used in Li‐ion cells and the recent advances in these materials. Copyright © 2017 John Wiley & Sons, Ltd.     

A di‐tert‐butyl acrylate monomer for controlled radical photopolymerization

A new di‐tert‐butyl acrylate (diTBA) monomer for controlled radical polymerization is reported. This monomer complements the classical use of tert‐butyl acrylate (TBA) for synthesis of poly(acrylic acid) by increasing the density of carboxylic acids per repeat unit, while also increasing the flexibility of the carboxylic acid side‐chains. The monomer is well behaved under Cu(II)‐mediated photoinduced controlled radical polymerization and delivers polymers with excellent chain‐end fidelity at high monomer conversions. Importantly, this new diTBA monomer readily copolymerizes with TBA to further the potential for applications in areas such as dispersing agents and adsorbents. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 801–807     

An experimental and theoretical study of butyl methacrylate in situ radical polymerization kinetics in the presence of graphene oxide nanoadditive

The butyl methacrylate radical polymerization kinetics in the presence of graphene oxide nanoadditive is studied both experimentally and theoretically. The experimental study includes the formation of graphite oxide from the oxidation of graphite and its subsequent transformation to graphene oxide (GO) after ultrasonication and in situ polymerization. Monomer conversion versus time was monitored gravimetrically at various reaction temperatures and initial GO fractions. Formation of GO was verified by X‐ray diffraction spectra and the number and weight average molecular weights of the final polymer were obtained from GPC measurements. A detailed theoretical kinetic model was further developed. The model predictions were found to be in satisfactory agreement with the experimental data. The presence of GO was found to result in reduced initiator efficiency verified theoretically and explained through side reactions of primary radicals. Finally, nanocomposites showed enhanced thermal stability compared to neat PBMA. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1433–1441     

Formation of homogeneous nanocomposite films at ambient temperature via miniemulsion polymerization using graphene oxide as surfactant

A convenient and industrially scalable method for synthesis of homogeneous nanocomposite films comprising poly(styrene‐stat‐butyl acrylate) and nanodimensional graphene oxide (GO) or reduced GO (rGO) is presented. Importantly, the nanocomposite latex undergoes film formation at ambient temperature, thus alleviating any need for high temperature or high pressure methods such as compression molding. The method entails synthesis of an aqueous nanocomposite latex via miniemulsion copolymerization relying on nanodimensional GO sheets as sole surfactant, followed by ambient temperature film formation resulting in homogeneous film. For comparison, a similar latex obtained by physical mixing of a polymer latex with an aqueous GO dispersion results in severe phase separation, illustrating that the miniemulsion approach using GO as surfactant is key to obtaining homogeneous nanocomposite films. Finally, it is demonstrated that the GO sheets can be readily reduced to rGO in situ by heat treatment of the film. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2289–2297     

A degradable atom transfer radical polymerization inimer: Synthesis,polymerization, and cleavage of the resulting polymer products

A novel degradable inimer for atom transfer radical polymerization (ATRP), 2‐(6‐(2‐((2‐bromo‐2‐methylpropanoyl)oxy)ethyl)pyridin‐2‐yl)ethyl methacrylate (PyDEBrMΑ), was synthesized by the two‐step esterification of 2,6‐pyridinediethanol, first with α‐bromoisobutyryl bromide in order to introduce the initiator moiety, and then with methacryloyl chloride in order to introduce the monomer moiety. PyDEBrMA was subsequently used to initiate the self‐condensing ATRP of methyl methacrylate (MMA) to obtain a hyperbranched MMA homopolymer which could be cleaved at the PyDEBrMA residue either by treatment under mildly alkaline hydrolysis conditions (sodium deuteroxide in d₆‐DMSO at room temperature) or thermolysis at 150 °C. The lability of the PyDEBrMA residue arises from the presence in its structure of two 2‐(pyridin‐2‐yl)ethyl ester moieties. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2831–2839