Synthesis and Ring Opening Polymerization of a New Functional Lactone, α‐Iodo‐ε‐caprolactone: A Novel Route to Functionalized Aliphatic Polyesters

A new functional lactone, α‐iodo‐ε‐caprolactone (αIεCL), was synthesized from ε‐caprolactone by anionic activation using a non‐nucleophilic strong base (lithium diisopropylamide) followed by an electrophilic substitution with iodine chloride. Ring‐opening (co)polymerizations of the resulting monomer with ε‐caprolactone were carried out using tin 2‐ethylhexanoate as a catalyst in toluene at 100 °C. Homopolymerization of αIεCL was achieved, and poly(αIεCL) was fully characterized by SEC, ¹H NMR and elemental analysis. Random copolymerizations of αIεCL with εCL were controlled with experimental molecular weights close to the theoretical values, narrow molecular weight distributions and a good agreement between experimental and theoretical molar compositions of αIεCL.

     

乙烷族卤代烃的微扰软链状态方程

本文将微扰软链理论应用于乙烷族卤代烃状态方程的研究,该方程包含三个物性参数,表征分子非球形度的参数c、Lennard-Jones软球直径σ和表征能量的参数ε/k。本文拟合得到了12种乙烷族卤代烃类物质的方程参数。与NIST软件计算结果比较表明,该方程对单相区和两相区的pvT性质均有较好的再现性。本文还发现该类物质的方程参数与分子结构之间存在某种规律性关系。     

Identification and determination of major flavonoids in rat urine by HPLC-UV and HPLC-MS methods following oral administration of Dalbergia odorifera extract

Flavonoids are the main active constituents of Dalbergia odorifera. The excretion of the major flavonoids in rat urine after oral administration of D. odorifera extract was investigated by HPLC-UV and HPLC-MS methods. Utilizing the HPLC-MS technique, 18 flavonoids, including five isoflavones, four isoflavanones, four neoflavones, two flavanones, two chalcones and one isoflavanonol were identified in free form in a urine sample based on the direct comparison of the corresponding tR, UV maximum absorbance (lambda(max)) values and MS data with the authentic standards. The amounts of the prominent flavonoids, (3R)-4'-methoxy-2',3,7-trihydroxyisoflavanone and vestitone, were determined by HPLC-UV with the internal standard method, and the validation procedure confirmed that it afforded reliable analysis of these two analytes in urine after oral administration of D. odorifera extract.     

卤代有机污染物的光化学降解

包括全氟或部分氟代化合物（PFCs）、氯代有机物（COCs）以及溴代有机物（BOCs）等的卤代有机污染物（halogenated organic contaminants,HOCs）排放到环境中会表现出持久性有机污染物的特征,因此涉及HOCs性质、光吸收与量子效应、材料与界面特性、环境条件等方面优化的光化学清除方法成为一个重要的研究方向。基于此,本文归纳分析了光激发催化剂产生活性物种如h_VB⁺、e_CB^-、 ·OH、e_aq^-等氧化或还原全氟辛酸、多氯联苯、多溴联苯醚的反应机理及直接光解机理,指出HOCs的光化学降解主要是通过其与活性物种之间电子转移或其激发态光致还原脱卤来实现,认为光催化材料和反应过程优化设计是影响光催化降解HOCs的重要因素。基于目前已经取得的研究发现与成果,从界面电子转移、材料能带信息、反应与分离集成化等方面提出本领域未来学术与技术层面值得深入探索的关键问题。     

电子自旋共振作为探针研究卤代溶剂的专属性效应

4-羟基-2,2,6,6-四甲基哌啶-1-氧自由基(4-OH-TEMPO)电子自旋共振的超精细耦合常数AN与溶剂极性的微观反应常数ET(30)和溶剂受体数AN呈现线性正相关. 并且在介电常数或偶极矩接近时, 含卤溶剂中超精细耦合常数AN普遍偏高. 除了一般的溶剂效应外, 在含卤溶剂中超精细耦合常数AN偏大的原因与专属性的卤键作用有关. 理论计算结果辅助印证了这一结论.     

Halide anions are formed from reactions between atomic metal anions and halogenated aromatic molecules

Atomic metal anions (AMAs) Fe^–, Cs^–, Cu^– and Ag^– were generated in the gas phase by collisionally decomposing the corresponding metal‐oxalate anion. Mass selected AMAs were allowed to react with halogenated and nitrated molecules (C6H5Cl, C6H4Cl2, C6H3Cl3, C6H5I, C6H5Br and C6H5NO2) in the collision hexapole of a triple‐quadrupole mass spectrometer. Observed reactions include the predominant formation of X^– (X = Cl, Br and I), as well as FeCl^–, FeCl2^– and FeCl3^– when Fe‐ reacted with the mono, di and tri‐chlorobenzenes; reactions between 1,4‐dichlorobenzene and Cs^– produced Cl^–, CsCl^– and CsCl2^–; reactions involving iodobenzene also produced, CsI^–, CsI2^– and AgI^–. The results suggest that the reaction to form X^– (X = Cl, Br, I and NO2) may be a promising route to improving the detection efficiency by mass spectrometry for such analytes. Copyright © 2016 John Wiley & Sons, Ltd.     

具有光引发活性RAFT链转移剂的合成与应用

以4-溴甲基二苯甲酮,3-巯基丙酸和二硫化碳为原料合成了RAFT链转移剂——3-(4-苯甲酰基苯基甲硫基硫代羰基硫基)丙酸(2),产率91.5%,其结构经NMR,IR和元素分析表征。以2为RAFT链转移剂和光引发剂,通过甲基丙烯酸烯丙酯的乳液聚合制得反应性聚甲基丙烯酸烯丙酯。     

Further Insight into the Photostability of the Pyrene Fluorophore in Halogenated Solvents

Pyrene fluorophores of pyrene‐functionalized CdSe quantum dots (QD@Py), as well as alkylpyrene and pyrene itself (Py), undergo fast degradation in aerated chloroform under ultraviolet‐A (UV‐A, 316<λ<400 nm) illumination. Steady‐state fluorescence studies of irradiated chloroform solutions of QD@Py show formation of new bands, red‐shifted compared to that of the pyrene moiety. Similar behaviour is observed for pyrene and the alkylpyrene system. Column chromatography of the pyrene photolysate in chloroform allowed us to isolate photoproducts arising from pyrene degradation, and to obtain information on the structure of the photoproducts responsible for the emission bands. The most predominant photoproducts were those originating from the reaction of pyrene with dichloromethyl radicals. The phototransformation of QD@Py and the alkylpyrene involves mainly detachment of the alkyl chain from the aromatic ring, induced also by dichloromethyl radicals, and oxidation of the alkyl chain at the benzylic position was detected as well. By contrast, these pyrene systems show a high photostability in aerated dichloromethane. Transient absorption measurements showed formation of both pyrene triplet and pyrene radical cation for all pyrene systems in these halogenated solvents. The yield of pyrene radical cations for Py is higher than for QD@Py and the alkylpyrene. In addition, pyrene radical cations were longer‐lived in dichloromethane than in chloroform. The reason for the pyrene photostability in dichloromethane is the different reactivity of chloromethyl and dichloromethyl radicals towards pyrene and oxygen. These studies show that the use of dichloromethane can be a suitable alternative to chloroform when the good solubility properties of these halogenated solvents are needed to dissolve pyrene when this chromophore is used as a fluorescent probe.