N-Heterocyclic Carbene Stabilized Dicarbondiphosphides: Strong Neutral Four-Membered Heterocyclic 6π-Electron Donors

In contrast to cyclic π-conjugated hydrocarbons, the coordination chemistry of inorganic heterocycles is less developed. Dicarbondiphosphides stabilized by N-heterocyclic carbenes (NHCs) NHC→C₂P₂←NHC ( 1 a , b ) (NHC=IPr or SIPr) contain a four-membered C₂P₂ ring with an aromatic 6π-electron configuration. These heterocycles coordinate to a variety of complex fragments with metals from groups 6, 9, and 10, namely [M⁰(CO)₃] (M=Cr, Mo), [Co^I(CO)₂]⁺, or [Ni^IIBr₂], through an η⁴-coordination mode, leading to complexes 2 a , b , 3 a , b , 5 a , b , and 6 a , b , respectively. These complexes were characterized by X-ray diffraction methods using single crystals, IR spectroscopy, and DFT calculations. In combination these methods indicate that 1 a , b behave as exceptionally strong 6π-electron donors.     

乙醇胺功能化石墨烯的制备与表征

乙醇胺在温和条件下与氧化石墨烯反应, 然后经水合肼还原得到功能化的石墨烯. 干燥的功能化石墨烯经超声处理后, 可稳定分散于水、乙醇、丙酮和N,N二甲基甲酰胺(DMF)等溶剂中. 原子力显微镜(AFM)、透射电镜(TEM)分析表明功能化石墨烯平均厚度为3～4 nm. 傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)、X射线衍射(XRD)对功能化石墨烯的结构分析表明: 乙醇胺与氧化石墨烯发生了化学反应, 并通过共价键连接到石墨烯的六元环上. TG结果表明功能化石墨烯的热稳定性比氧化石墨烯有所提高, 但低于还原氧化石墨烯.     

Tm:Lu_3Al_5O_(12)晶体的生长与光谱性能研究

采用提拉法生长高质量的纯LuAG晶体和4%(原子分数)Tm:LuAG晶体.对晶体的晶胞参数和光谱性能进行了详细的表征.研究发现:Tm~(3+)的掺入没有改变LuAG基质的晶体结构;吸收光谱中255 nm处的吸收带是由Fe~(3+),Fe~(2+)引起的;晶体在782 nm处的吸收峰,与商用AlGaAs二极管的发射波长匹配良好,吸收截面为5.07×10~(-21) cm~2.Tm:LuAG晶体在2 μm波段的荧光峰对应~3F_4-~3H_6能级之间的跃迁,荧光寿命长达11.9 ms,有利于激光的高能量调Q输出.结果表明,Tm:LuAG晶体是2 μm激光器中很有发展潜力的增益介质,将会替代Tm:YAG晶体应用于激光雷达系统.     

Hydrothermal Synthesis of a 3D Polymeric Cobalt(II) Carboxylate Derivative from 1,2,4,5‐Benzenetetracarbonitrile

The metal‐organic complexes Co₂(terpy)₂(btec)·H₂O 1 (terpy = 2,2′:6′,2″‐terpyridine, btec = 1,2,4,5‐benzenetetracarboxylate) was synthesized by hydrothermal synthesis method, using 1,2,4,5‐benzenetetracarbonitrile, terpy and CoAc₂·4H₂O. Single crystal X‐ray diffraction showed that each btec^4– ligand links four Co^II atoms and each Co^II atom links to two btec^4– ligands forming a 1D double‐chain structure. Furthermore, the chains pack together through short face–face π–π interactions forming a 3D supramolecular structure. Additionally, the magnetic measurements show antiferromagnetic interactions among metal ions for compound 1 .     

Conjugated trees with minimum general Randi? index

The general Randi? index R_α(G) is the sum of the weights (d_G(u)d_G(v))^α over all edges uv of a (molecular) graph G, where α is a real number and d_G(u) is the degree of the vertex u of G. In this paper, for any real number α≤−1, the minimum general Randi? index R_α(T) among all the conjugated trees (trees with a Kekulé structure) is determined and the corresponding extremal conjugated trees are characterized. These trees are also extremal over all the conjugated chemical trees.     

五引物单管聚合酶链反应(PCR)扩增法快速测定人CYP2D6*10等位基因的类型

以人CYP2D6*10等位基因位点为研究对象,建立了一种由5条引物同时PCR扩增在单管中进行等位基因快速检测的新方法。该方法在等位基因特异性扩增法的基础上,在内引物3′端引入了一个人工错配碱基并在5′端附加一段“尾巴”作为引物的锚定部分,使扩增反应的特异性得到了提高。本实验所建立的方法可在单管中同时完成SNP3种可能等位基因类型的快速检测。实测了47份样品的CYP2D6*10等位基因的类型,并随机对其中20份样品的测定结果用RFLP法进行了验证,结果完全一致。结果表明本法简便、快速,结果准确。     

Dispersive solid‐phase extraction combined with dispersive liquid‐liquid microextraction for simultaneous determination of seven succinate dehydrogenase inhibitor fungicides in watermelon by ultra high performance liquid chromatography with tandem mass spectrometry

In this study, a simple and accurate sample preparation method based on dispersive solid‐phase extraction and dispersive liquid‐liquid microextraction has been developed for the determination of seven novel succinate dehydrogenase inhibitor fungicides (isopyrazam, fluopyram, pydiflumetofen, boscalid, penthiopyrad, fluxapyroxad, and thifluzamide) in watermelon. The watermelon samples were extracted with acetonitrile, cleaned up by dispersive solid‐phase extraction procedure using primary secondary amine, extracted and concentrated by the dispersive liquid‐liquid microextraction procedure with 1,1,2,2‐tetrachloroethane, and then analyzed by ultra high performance liquid chromatography with tandem mass spectrometry. The main experimental factors affecting the performance of dispersive solid‐phase extraction and dispersive liquid‐liquid microextraction procedure on extraction efficiency were investigated. The proposed method had a good linearity in the range of 0.1–100 µg/kg with correlation coefficients (r) of 0.9979–0.9999. The limit of quantification of seven fungicides was 0.1 µg/kg in the method. The fortified recoveries of seven succinate dehydrogenase inhibitor fungicides at three levels ranged from 72.0 to 111.6% with relative standard deviations of 3.4–14.1% (n = 5). The proposed method was successfully used for the rapid determination of seven succinate dehydrogenase inhibitor fungicides in watermelon.     

Rare earth oxide-doped titania nanocomposites with enhanced photocatalytic activity towards the degradation of partially hydrolysis polyacrylamide

Rare-earth oxide-doped titania nanocomposites (RE³⁺/TiO₂, where RE = Eu³⁺, Pr³⁺, Gd³⁺, Nd³⁺, and Y³⁺) were prepared by a one-step sol-gel-solvothermal method. The products exhibited anatase phase structure, mesoporosity, and interesting surface compositions with three oxygen species and two titanium species. The products were used as the photocatalysts to degrade a partially hydrolysis polyacrylamide (HPAM) under UV-light irradiation, a very useful polymer in oil recovery. For comparison, Degussa P25 and as-prepared pure TiO₂ were also tested under the same conditions. The enhanced photocatalytic activity was obtained on as-prepared Eu³⁺ (Gd³⁺, Pr³⁺)/TiO₂ composites, and the reasons were explained. Finally, the degradation pathway of HPAM over the RE³⁺/TiO₂ composite was put forward based on the intermediates produced during the photocatalysis procedure.     

半导体光放大光纤环形激光器的偏振混沌与相干性

研究了基于半导体光放大器(SOA)的光纤环形激光器的偏振混沌光的特性及其相干性。实验采集激光器的输出功率和偏振度,得到了基于半导体光放大器的光纤环形激光器的输出从自发辐射到受激辐射、再到偏振态混沌激光辐射的演化过程。利用马赫-曾德尔(M-Z)干涉仪验证了混沌激光的相干性,并发现混沌干涉只有零级。测量不同光程差时干涉仪的输出功率,计算相应的干涉条纹可见度,进一步算得混沌激光的相干时间约为40 ps。这一结果与根据光谱计算的该混沌激光的相干时间43 ps基本一致。实验还测得该混沌激光的相干性与半导体光放大器的电流无关。并指出了混沌激光相干应用于低相干光源探测领域的灵敏度和分辨力优势。