Synthesis and characterization of copolymaleimides containing 4‐cyanobiphenyl‐based side groups for nonlinear optical applications

We report the synthesis of a nematic copolymer, P(CBMS‐co‐M₃), prepared by free radical polymerization of an equimolecular mixture of p‐(4‐cyanobiphenyl‐4′‐yloxy)methylstyrene (CBMS) and N‐[3‐(4‐cyanobiphenyl‐4′‐yloxy)propyl]maleimide (M₃) and two isotropic alternating copolymers, P(S‐alt‐M_n) (n = 3,6) prepared by chemical modification of poly(styrene‐alt‐maleimide), P(S‐alt‐M), by n‐(4‐cyanobiphenyl‐4′‐yloxy)alkan‐1‐ol. These copolymaleimides were characterized by NMR, DSC, and optical microscopy. Some corona poling experiments were performed and the second harmonic coefficients d₃₁ and d₃₃ were measured. It was shown that one can gain in net polar ordering by starting with a liquid crystalline system. The ratio d₃₃/d₃₁ was much larger than 3, in agreement with the molecular statistical models for electric field poling of liquid crystals. At ambient conditions, changes of d₃₃ and d₃₁ are 15% over 325 days. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 513–524, 1999     

硒功能化杯芳烃载体银离子选择性膜电极的研究

合成6个硒功能化杯芳烃为载体,采用双层夹心膜电位法直接测定了溶剂聚合物膜中载体与金属离子生成的络合物生成常数。制备并考察了以硒功能化杯芳烃为载体的银离子选择性电极的性能,发现以载体6为银离子选择性电子的载体,制成的膜电极,用作Ag^ 电位滴定Cl^-的指示电极,效果最佳。     

Complexing Polymer Films in The Preparation of Modified Electrodes for Detection of Metal Ions

Summary: The complexing properties of poly (3-(pyrrol-1-yl)propylmalonic acid) (poly1) and poly(N,N′-ethylenebis[N-[(3-(pyrrole-1-yl)propyl) carbamoyl) methyl]-glycine (poly2) coated electrodes (C|poly1 and C|poly2) towards Cu(II), Pb(II), Hg(II) and Cd(II) cations using the open circuit chemical preconcentration-anodic stripping technique were studied. Sorption process of metal cations onto complexing surfaces was readily investigated through the combination of a chemical pre-concentration-anodic stripping technique with a Langmuir isotherm model. The modified electrodes were used for the voltammetric determination of Cu(II), Pb(II), Hg(II) and Cd(II) ions, giving low detection limits for Cu(II) (5 × 10⁻⁹ mol L⁻¹) and Pb(II) (5 × 10⁻¹⁰ mol L⁻¹). The ability of the modified electrodes to analyze Cu(II) ions in natural sample has been demonstrated by the analysis of a tap water sample. The results of the preconcentration process under competitive conditions clearly shows that the selectivity of complexing molecular electrode materials can be subtly tuned upon playing on the accumulation time, polymer thickness and/or memory effect of the binding polymers, opening up new avenues towards evolutive and efficient smart sensing materials.     

Layer-by-layer functionalized porous Zinc sulfide nanospheres-based solid-phase extraction combined with liquid chromatography time-of-flight/mass and gas chromatography-mass spectrometry for the specific enrichment and identification of alkaloids from Crinum asiaticum var. sinicum

The current widely utilized polymer or C8, C18 end-capped material-based sorbents for solid-phase extraction could not capture alkaloids well only based on “like dissolves like” principle. In this paper, a layer-by-layer functionalized porous Zinc sulfide nanospheres-based solid-phase extraction (SPE) combined with liquid chromatography time-of-flight/mass spectrometry (LC-TOF/MS) and gas chromatography-mass spectrometry (GC-MS) was developed for the specific enrichment and identification of alkaloids from complex matrixes, Crinum asiaticum var. sinicum crude extracts. The functionalized porous Zinc sulfide nanospheres were prepared by the amidation reaction of poly-(acrylic acid) (PAA) homopolymer with amino groups onto the porous ZnS nanospheres. Tandem LC-TOF/MS spectrometry presented that the almost all of the twenty-three main peaks in elution fraction from the SPE could be inferred as alkaloids with ion of mass according to the nitrogen rule and hit formula with Peak View1.2@software from AB SCIEX, and seven alkaloids including two new found chemical entities were directly identified from their GC-MS spectra and retention indices. We believe that this SPE protocol can also be utilized in the future to selectively enrich alkaloids from extracts of other plant species.     

官能团化N,C双齿N-杂环卡宾配合物研究进展

综述了官能团化N,C双齿N-杂环卡宾金属配合物研究的最新进展,着重讨论了这些配合物对各种化学反应的催化性能.     

负载生物活性功能基聚醚氨酯的表面自由能与表面血液相容性研究

水相接触角;负载生物活性功能基聚醚氨酯的表面自由能与表面血液相容性研究     

Precise Block‐Copolymers by Efficient Coupling of End‐Functionalized Polymers Using Phosgene

Summary: We report the synthesis of well‐defined block copolymers by covalent coupling of hydroxy end‐functionalized polymers. Using the high volatility of the coupling agent phosgene as compared to the solvent, very high conversion (up to 96%) is obtained in a one‐pot reaction with as little as 10⁻⁵ moles of each of the reacting polymers, even without prior purification of the as‐received reagents. This has potential as an alternative to the currently practiced method of sequential living polymerization of constituent monomers, with the added advantage of direct knowledge and control over the length distribution of each block.

Coupling of end‐functionalized polymers using phosgene to form block copolymers of controlled composition.     

多功能光学活性丁二醇衍生物的合成和结构

通过新的合成策略,以手性合成子3和具有生物活性的有机碱类化合物4为反应底物,利用Michael不对称加成反应,合成得到光学纯的5-(R)-［(1R,2S,5R)-(-)-氧基］-4-(R)-(杂环碱基)-2(5H)-呋喃酮(5). 加成物5通过还原反应得到了多功能光学活性的二醇类化合物6,产率为42%~82%,e.e.≥98%. 化合物6的化学结构得到了确认,其立体化学结构和绝对构型经X射线晶体学测定得到了确定.     

含醛基功能化离子液体为载体液相合成氨基醚类化合物

以1-甲基咪唑、对二氯苄、对羟基苯甲醛和四氟硼酸钠为原料, 制备了一种含醛基的新型功能化离子液体1-(4-对甲酰基苯氧基亚甲基苄基)-3-甲基咪唑四氟硼酸盐(简写为[fmmim][BF4]). 为拓展功能化离子液体为载体的液相合成反应体系, 以该含醛基功能化离子液体为可溶性液相载体, 进行了Williamson醚化的合成反应, 较高产率和纯度得到了一系列氨基醚类化合物, 切割后得到的目标化合物不需要进行进一步的柱色谱纯化处理, 产率为81%～85%, 纯度为96%～99%. 回收得到的功能化离子液体可以重复套用多次而不影响其功效, 目标化合物的产率在81%～84%之间波动. 结果表明该方法可高效率地用于基于Williamson醚化反应的液相组合化学合成.     

Chain Walking Ethylene Copolymerization with an ATRP Inimer for One‐Pot Synthesis of Hyperbranched Polyethylenes Tethered with ATRP Initiating Sites

A one‐pot procedure for the synthesis of hyperbranched polyethylenes tethered with ATRP initiating sites by chain walking ethylene copolymerization with an acrylate‐type ATRP inimer, 2‐(2‐bromoisobutyryloxy) ethyl acrylate (BIEA) is reported. Because of its ability to incorporate acrylate‐type comonomers and tolerance toward the α‐bromoester group, the chain walking Pd‐diimine catalyst, [(ArNC(Me) (Me)CNAr)Pd(CH₃)(NCMe)]SbF₆ (Ar = 2,6‐(iPr)₂C₆H₃), allowed the successful synthesis of a series of hyperbranched copolymers tethered with 2‐bromoisobutyryl groups at different densities. These copolymers may serve as polyfunctional macroinitiators for the ATRP of functional monomers to further synthesize core‐shell structured functionalized copolymers with a hyperbranched polyethylene core grafted with side chains of the functional monomers.