Magnetic nanoparticles as an orthogonal support of polymer resins: applications to solid-phase suzuki cross-coupling reactions

[reaction: see text] Most of the reactants immobilized on conventional solid-phase resins are buried inside the interiors of lightly cross-linked polystyrene beads. An orthogonal support of solid-phase resins needs to be small enough to penetrate the interpolymeric chain spaces of a swollen resin to reach reaction sites. In this paper, we report the use of magnetic nanoparticles ( approximately 4 nm) as an orthogonal matrix to assist solid-phase reactions. A magnetic nanoparticle-supported homogeneous Pd catalyst was employed for promoting the Suzuki cross-coupling of an aryl halide on resins and an excessive arylboronic acid in solution. The workup separating three components (the catalyst, product, and remaining arylborate) is a chromatography-free process. The Pd catalyst was magnetically isolated and recycled from the reaction mixture by applying an external magnetic field. Then, a filtration process was followed to recover the excess borate reagent from the resins/product. Our work here presents the first example of an orthogonal matrix of solid-phase resins and shows the promise of employing nanomaterials in organic synthesis.     

若干有机分子的二阶非线性光学极化系数色散关系

在INDO/CI方法基础上, 用自己编制的计算二阶非线性极化系数β_(ijk)程序, 计算了苯胺、硝基苯、对硝基苯胺和4-硝基-4′-胺基二苯乙烯的β_(ijk), 并研究了其对外部激光场频率的依赖关系。结果表明, 分子内的电荷转移是产生非线性光学现象的根本原因, 而作为外因的激光场对二阶非线性光学系数的大小和方向也有直接的重要作用。当激光场频率与分子的共振频率接近时, 二阶非线性极化系数变得非常大, 在共振频率附近, β_(ijk)改变符号且Kleinman对称性被打破。     

Synthesis and molecular characterization of the coordination polymer [Pb(2,2′-Bipy)(NO3)2(H2O)] n

A new coordination polymer [Pb(2,2′-Bipy)(NO₃)₂(H₂O)] _n has been successfully synthesized and characterized (where 2,2′-Bipy = 2,2′-bipyridine). The crystal structure of the polymer was determined by single-crystal X-ray diffraction, crystallizing in the monoclinic crystal system, space group P2₁/n with unit cell parameters: a = 7.1673(5), b = 9.8706(6), c = 19.1825(12) Å; β = 90.0780(10)°; V = 1357.08(15) ų, and Z = 16. The Pb atom was six-coordinated with N(1) and N(2) from 2,2′-Bipy, O(2), O(3), and O(6) in nitrate; O(1) from coordinated water, forming a slightly distorted octahedral geometry. The structure units aggregate together to give birth to the infinite 1D chains via bridged nitrate, and 2D networks and three-dimensional frameworks were obtained through hydrogen bonding and π-π-stacking interaction among aromatic rings, respectively.     

并行FORTRAN程序设计技术探索

简要叙述了并行程序设计语言ＣＭＦｏｒｔｒａｎ的计算模式、并行数据结构及其主要特征．并对Ｆｏｒｔｒａｎ７７和Ｆｏｒｔｒａｎ９０上的扩展部分作了概要描述．     

有机磷昆虫不育剂的研究——N-乙撑亚胺基,烷氧基(胺基,取代胺基)磷酰胺与硫代磷酰胺类化合物的合成

含磷乙撑亚胺化合物的研究开始于本世纪中叶,1950年Bestian首先合成了一系列这类化合物。其中三乙撑亚胺基氧化膦(Tepa)及其硫代物(ThioTepa)以及甲基取代衍生物(Me-Tepa)。     

对氨基偶氮苯的同步辐射光电离与光离解

In this paper, the photoionization and photodissociative ionization processes of p-aminoazobenzene (pAAB, C12H11N3) using coincidence technology with vacuum ultraviolet synchrotron radiation (SR) photoionizaton mass spectroscopy are reported. The ionization potential (IP) of this molecule and the appearance potentials (AP) of the important ionic fragments from the SR photodissociative ionization of pAAB have been measured. On the basis of the IP(C12H11N3) and AP measured in this experiment and the IP(C6H5) from the literature, the dissociative energy D 0(C 6H 5-N 2C 6H 4NH 2),D 0(C 6H + 5-N 2C 6H 4NH 2),D 0(C 6H 5-N 2C 6H 4NH + 2),D 0(C 6H 5N 2-C 6H 4NH 2 +) and ionization potential of free radical N 2C 6H 4NH 2 have been evaluated. Based on the results of the mass spectroscopy of pAAB obtained with SR photoionization, the possible channels of photodissociative ionization of pAAB have been analyzed. The processes(molecular ions or the fregmental ions) giving rise to the ions C 6H + 5 and C 6H 6N + need further study.     

一类奇异抛物方程的超过程解法

对于如下一类奇异非线性抛物型方程：ｔｕ（ｔ,ｘ）＝Δｕ（ｔ,ｘ）－ｕβ（ｔ,ｘ）,ｘ∈Ｂ（０,ａ）,ｕ（０,ｘ）＝０,ｕ（ｔ,ｘ）｜ｘ｜→ａ－→∞,ｔ＞０,这里,１≤β≤２,Ｂ（ｏ,ａ）表示以ｏ为中心,以ａ为半径的Ｒｄ中的闭球,利用超过程的理论,给出了它的概率解法,从而推广了文［１］相应的结论     

价值引领融入“无机化学与化学分析”的课程思政建设

将课程思政应用到"无机化学和化学分析"教学中,更好发挥其价值引领作用。开展课程思政建设,应做到守正与创新。本文以价值引领为切入点,介绍如何将思想政治教育有机融入课程内容设置和课堂讲授等环节,力求培养学生的家国情怀、国际视野、法治意识、生态意识、工程伦理、人文关怀等科学素养,深入践行立德树人,提高本科教学质量。     

Facile Synthesis of 2‐Alkylthio‐3‐alkyl‐5‐phenylmethylidene‐4H‐imidazol‐4‐ones

2‐Alkylthio‐3‐alkyl‐5‐phenylmethylidene‐4H‐imidazol‐4‐ones 6 were synthesized by N‐alkylation and S‐alkylation of 2‐thioxo‐5‐phenylmethylidene‐4‐imidazolidinone 5, which was obtained via cyclization of vinyl isothiocyanate 4 with excess ammonium hydroxide (28% NH₃ in water).     

CO2 sorption in wet ordered mesoporous silica kit-6: effects of water content and mechanism on enhanced sorption capacity

The sorption isotherms of CO₂ in wet ordered mesoporous silica KIT-6 with different amounts of pre-adsorbed water were firstly collected experimentally using a volumetric method in the temperature range of 275–281 K. The isotherms show an inflection point indicating CO₂ hydrates form in the pore spaces which is proofed by the enthalpy change calculated at the inflection pressure, and the quantity of water content shows considerable effect on the sorption capacity of CO₂. The highest enhancement of sorption capacity in the presence of water is observed in wet KIT-6 sample with water loadings of 2.48, which is about 12.80 mmol/g and 1.86 times than that on dry sample. However, the saturation capacity is still far less than that what can be stored merely in the form of hydrates due to the low ratio of water utilization because of the large pore and the polar surface of KIT-6.