High‐performance liquid chromatographic enantioseparation of (RS)‐bupropion using isothiocyanate‐based chiral derivatizing reagents

A high‐performance liquid chromatographic (HPLC) method for enantioseparation of bupropion was developed using two isothiocyanate‐based chiral derivatizing reagents, (S)‐1‐(1‐naphthyl) ethyl isothiocyanate, (S)‐NEIT, and (R)‐α‐methyl benzyl isothiocyanate, (R)‐MBIT. The diastereomers synthesized with (S)‐NEIT were enantioseparated by reversed‐phase HPLC using gradient elution with mobile phase containing water and acetonitrile, whereas diastereomers synthesized with (R)‐MBIT were enantioseparated using triethyl amine phosphate buffer and methanol. Derivatization conditions were optimized and the method was validated for accuracy, precision and limit of detection. The limit of detection was found to be 0.040–0.043 µg/mL for each of the diastereomers prepared with (S)‐NEIT. Copyright © 2013 John Wiley & Sons, Ltd.     

Hydrophobic cryogels for DNA adsorption: Effect of embedding of monosize microbeads into cryogel network on their adsorptive performances

As alternative hydrophobic adsorbent for DNA adsorption, supermacroporous cryogel disks were synthesized via free radical polymerization. In this study, we have prepared two kinds of cryogel disks: (i) poly(2‐hydroxyethyl methacrylate‐N‐methacryloyl‐l ‐tryptophan) [p(HEMA‐MATrp)] cryogel containing specific hydrophobic ligand MATrp; and (ii) monosize p(HEMA‐MATrp) particles synthesized via suspension polymerization embedded into p(HEMA) cryogel structure to obtain p(HEMA‐MATrp)/p(HEMA) composite cryogel disks. These cryogel disks containing hydrophobic functional group were characterized via swelling studies, Fourier transform infrared spectroscopy, elemental analysis, surface area measurements and scanning electron microscopy. DNA adsorption onto both p(HEMA‐MATrp) cryogel and p(HEMA‐MATrp)/p(HEMA) composite cryogels was investigated. Maximum adsorption of DNA on p(HEMA‐MATrp) cryogel was found to be 15 mg/g polymer. Otherwise, p(HEMA‐MATrp)/p(HEMA) composite cryogels significantly increased the DNA adsorption capacity to 38 mg/g polymer. Composite cryogels could be used repeatedly without significant loss on adsorption capacity after 10 repetitive adsorption–desorption cycles. Copyright © 2013 John Wiley & Sons, Ltd.     

Modeling Diffusion in Foamed Polymer Nanocomposites

Two‐way multicomponent diffusion processes in polymeric nanocomposite foams, where the condensed phase is nanoscopically reinforced with impermeable fillers, are investigated. The diffusion process involves simultaneous outward permeation of the components of the dispersed gas phase and inward diffusion of atmospheric air. The transient variation in thermal conductivity of foam is used as the macroscopic property to track the compositional variations of the dispersed gases due to the diffusion process. In the continuum approach adopted, the unsteady‐state diffusion process is combined with tortuosity theory. The simulations conducted at ambient temperature reveal distinct regimes of diffusion processes in the nanocomposite foams owing to the reduction in the gas‐transport rate induced by nanofillers. Simulations at a higher temperature are also conducted and the predictions are compared with experimentally determined thermal conductivities under accelerated diffusion conditions for polyurethane foams reinforced with clay nanoplatelets of varying individual lamellar dimensions. Intermittent measurements of foam thermal conductivity are performed while the accelerated diffusion proceeded. The predictions under accelerated diffusion conditions show good agreement with experimentally measured thermal conductivities for nanocomposite foams reinforced with low and medium aspect‐ratios fillers. The model shows higher deviations for foams with fillers that have a high aspect ratio.     

漆酚铝高分子修饰碳糊电极用于溶出伏安法测定痕量银

漆酚铝树脂;漆酚铝高分子修饰碳糊电极用于溶出伏安法测定痕量银     

不对称diels-Alder反应中的手性催化剂

本文综述了近年来不对称Diels-Alder反应中手性催化剂研究的进展,对各类手性催化剂的性能和特点作了简要介绍.     

A New Strategy for the Synthesis of Polytrithiocarbonates Using a Polymeric Support System

A new polymerization strategy, consisting of nucleophilic substitution reaction between CS₃^2‐, immobilized on a polymeric support, and dimethyl α,α′‐dibromoalkylanedioate in solution, leads to the formation of polytrithiocarbonates. When n = 0, 1 in CH₃OOCCHBr(CH₂)_nCHBrCOOCH₃ (α,α′‐dibromoalkylanedioate), only five‐ or six‐membered cyclic trithiocarbonates were obtained; n ≥ 2 resulted in the formation of polytrithiocarbonates.     

Polymere Iodoplumbate – Synthese und Kristallstrukturen von (Pr3N–C2H4–NPr3)[Pb6I14(dmf)2] · 4 DMF, (Pr3N–C2H4–NPr3)[Pb(dmf)6][Pb5I14] · DMF und (Me3N–C2H4–NMe3)2[Pb2I7]I

Polymeric Iodoplumbates – Synthesis and Crystal Structures of (Pr₃N–C₂H₄–NPr₃)[Pb₆I₁₄(dmf)₂] · 4 DMF, (Pr₃N–C₂H₄–NPr₃)[Pb(dmf)₆][Pb₅I₁₄] · DMF, and (Me₃N–C₂H₄–NMe₃)₂[Pb₂I₇]I (Pr₃N–C₂H₄–NPr₃)[Pb₆I₁₄(dmf)₂] · 4 DMF ( 1 ) and (Pr₃N–C₂H₄–NPr₃)[Pb(dmf)₆][Pb₅I₁₄] · DMF ( 2 ) have almost the same composition, but completely different structures. Both compounds are formed selectively depending on the reaction and crystallization conditions. In 2 the Pb^II atoms are coordinated either by six bridging I^– ligands in the two-dimensional [Pb₅I₁₄]^4– network or by six DMF ligands in the [Pb(dmf)₆]²⁺ cations. In contrast, (Me₃N–C₂H₄–NMe₃)₂[Pb₂I₇]I ( 3 ) contains non-coordinating I^– anions between the iodoplumbate layers. The iodoplumbate anions in 2 and 3 consist of face and corner sharing PbI₆ octahedra, whereas in 1 PbI₆ and PbI₅(dmf) octahedra share common edges to form a one-dimensional polymeric section of the PbI₂ structure. (Pr₃N–C₂H₄–NPr₃)[Pb₆I₁₄(dmf)₂] · 4 DMF ( 1 ): Space group P1, a = 920.1(3), b = 1597.2(5), c = 1613.9(4) pm, α = 66.02(2), β = 84.53(2), γ = 85.99(2)°, V = 2156(1) · 10⁶ pm³; (Pr₃N–C₂H₄–NPr₃)[Pb(dmf)₆][Pb₅I₁₄]·DMF ( 2 ): Space group P2₁, a = 1201.21(9), b = 3031.1(2), c = 1294.96(9) pm, β = 108.935(7)°, V = 4459.8(5) · 10⁶ pm³; (Me₃N–C₂H₄–NMe₃)₂[Pb₂I₇]I ( 3 ): Space group Pnma, a = 2349.9(2), b = 1623.83(9), c = 980.75(7) pm, V = 3742.4(5) · 10⁶ pm³.     

Polymerization and Copolymerization of Some Monomers as Adducts with β-Cyclodextrin

The feasibility of chemical bond formation, especially in the chain-transfer reaction between polymer and β-cyclodextrin (β-CD) molecules in the products of the radiation polymerization of β-CD with vinylidene chloride (VDC) its adducts has been considered. The lack of these bonds in the polymerization products of similar β-CD adducts with methyl methacrylate (MM), styrene (St), a mixture of VDC and allyl chloride (AC) and a mixture of VDC and MM (10:90 molar ratio) has been established. On the basis of the results obtained the lack of chemical bonds in the polymerization product of β-CD· VDC adduct is suggested.     

A Convenient Synthesis of Phosphorines and Phospholidins by <Emphasis Type="Italic">Lawesson</Emphasis>’s Reagent and Microwave Irradiation

Summary. A new and simple method for the synthesis of 1,3,2-diazaphosphorines and 1,3,2-oxazaphosphorine was developed based on the reactions of Lawessons reagent with -aminopropionitriles and -hydroxypropionitrile. In addition, a rapid and facile synthesis of 1,3,2-diazaphospholidin-4-ones by the reaction of P(NEt₂)₃ with hindered diamino substrates under microwave irradiation was also achieved. The prepared phosphorines show herbicidal activity to some extent in the preliminary bioassays.     

Synthesis and Crystal Structure of a New Organic-inorganic Hybrid One-dimensional Polymer： [Zn（C8H23N5）]2（Pb3I10）

1 INTRODUCTION Recently, the organic-inorganic hybrid Ⅳa groupmetal halides with low-dimensional structure haveattracted much attention of chemists and physicistsdue to their particular properties and applications.For example, they are akin to “natural quantum-well”architectures and have tunable excitonic propertiesusually governed by the inorganic substructure andorganic component[1]; they have been applied assome technologically important materials, such assemiconductor materials in …