钼铁混合金属原子簇化合物[(η5-C5H5)4Mo4Fe2(μ3-S)5(CO)5]的合成和结构

(η~5-C_5H_5)_4Mo_4Fe_2(μ_3-S)_5(CO)_5 have been prepared from (η~5-C_5H_5)_2Mo_2(CO)_6 and Fe_8S_2(CO)_9 under toluene reflux for 14.5 hrs.The crystal and molecular structures of (η~5-C_5H_5)_4Mo_4Fe_2(μ_3-S)_5(CO)_5 were studied by X-ray structure analysis. The Crystallographic data are as follows: monoclinic, space group P2_1/n, unit cell: a=1.0589(4), b=1.7260(4), c=1.8963(4) nm, β=101.44(2)°, V=3.3967 nm, D_c=2.06 gcm~(-3) for Z=4, X-ray data were obtained over the range of 2°<2θ<50° via the ω-2θ scan mode with MoKα radiation on an Enraf-Nonius CAD4 diffractometer. The structure was solved by direct method (MULTAN) and refined by full matrix least-squares techniques for 3993 reflections with I>2σ(I), The final R=0.081. Figure 1 illustrates the configuration of the molecule (η~5-C_5H_5)_4Mo_4Fe_2(μ_3-S)_5(CO)_5, composing of a cubane-like (FeMo_3S_4) core and a trigonal pyramid (MoFe_2S) core, which linked by sharing Fe(1) atom.     

双核银络合物[Ag_2(dppm)_2(Py)_2(μ-Cl)]ClO_4的合成与结构

二-(二苯基膦)甲烷(dppm)是一种易与金属形成多核络合物的有机膦配体。我们用dppm作为配体合成了一系列银的多核络合物,并对其结构进行了研究。本文报导了其中一个双核化合物[Ag_2(dppm)_2(Py)_2(μ-Cl)]ClO_4的合成及晶体结构、分子结构的测定。     

用毛细管电泳-激光诱导荧光-增强型电荷耦合检测器测定痕量氨基酸

本文对用毛细管电泳－激光诱导荧光－增强型电荷耦合检测器测定氨基酸衍生物进行了研究。考察了荧光黄异疏氰酸酯衍生氨基酸的各种条件。在优化条件下，10－8～10－6mol／L浓度范围内精氨酸与其衍生物的荧光强度呈良好的线性关系，最小可衍生化的精氨酸浓度为5×10－10mol／L。     

流通池光度滴定法应用—络合反应中的质子释放数测定

用具有流通池的分光光度计作测定装置,建立了由平衡移动法测定络合反应中质子释放数的新方法。方法简单、快速,仅用一个标准溶液,适于在变更pH值范围内金属离子不发生水解和没有其他副反应的体系。     

Synthesis and characterization of diametrically substituted tetra-O-n-butylcalix[4]arene ligands and their chelated complexes of titanium,molybdenum, and palladium

The ligation properties of three new upper-rim-substituted calix[4]arene ligands, 5,17-bis(hydroxymethyl)-tetra-n-butoxycalix[4]arene ((HOCH2)2-nBu4Clx, 7), 5,17-bis((diphenylphosphinito)methoxy)-tetra-n-butoxycalix[4]arene ((PPh2OCH2)2-nBu4Clx, 8), and 5,17-bis((diphenylphosphino)methyl)-tetra-n-butoxycalix[4]arene ((PPh2CH2)2-nBu4Clx, 10) are reported herein. The newly prepared compounds differ from previously reported diametrically substituted calix[4]arene derivatives in that the lower-rim substituent was n-butyl. The presence of this lower-rim substituent did not reduce the inherent crystallinity of these complexes as purification of all materials occurred via simple crystallizations. The key precursor for the syntheses of 8 and 10 was 7, acquisition of which occurred in six steps starting from tetra-tert-butylcalix[4]arene, 1. Calix[4]arene derivatives include, tetra-n-butoxycalix[4]arene (nBu4Clx, 3), 5,11,17,23-tetrabromo-tetra-n-butoxycalix[4]arene (Br4-nBu4Clx, 4), 5,17-dibromo-tetra-n-butoxycalix[4]arene (Br2-nBu4Clx, 5), 5,17-bis(formyl)-tetra-n-butoxycalix[4]arene ((CHO)2-nBu4Clx, 6), and 5,17-bis(chloromethyl)-tetra-n-butoxycalix[4]arene ((ClCH2)2-nBu4Clx, 9), all of which were synthesized using modifications of existing procedures. Characterization of all compounds occurred, when possible, using 1H, 13C, and 31P NMR, elemental analyses, FAB-MS, ESI-MS, FT-IR, and X-ray crystallography. The solid-state structures of all calix[4]arene intermediates and ligands showed that the annulus adopted the pinched-cone conformation in which the average C(5)...C(17) intraannular separation was 4.5 +/- 0.4 A. Reaction of 7 with CpTiMe3 yielded the cis-chelate, CpTi(Me)[(OCH2)2-nBu4Clx] (11), quantitatively. Data obtained using ESI-MS (positive-ion mode) confirmed the monomer formulation showed above, and 1H NMR spectra provided sufficient information to deduce the nature of the Ti coordination sphere. Reaction of 8 with cis-Cl2Pd(NCPh)2 in refluxing benzene afforded cis-Cl2Pd[(PPh2OCH2)2-nBu4Clx] (12) in good yields. The monomeric identity of this compound was verified by both X-ray crystallography and positive-ion ESI-MS. The cis-bidentate calix[4]arene ligand did not undergo any noticeable contortion upon chelation of the PdCl2 fragment. Acid-promoted decomposition of 12 occurred in the presence of adventitious HCl and gaseous HCl, and the products of this decomposition were 9 and [mu2-ClPd(PPh2OH)(PPh2O)]2. In addition, chelates of 8 that contained Mo(CO)3L (L = NCMe (14a), NCEt (14b), and CO (14c)) showed that the mode of coordination was relatively insensitive to the identity of the metal. X-ray crystallography afforded views of the solid-state structures of 14b,c and, like 12, showed that the Mo(CO)3L fragment resided above the pinched-cone of the calix[4]arene. 1H NMR revealed that C-H/pi interactions existed between L (14a,b) and a phenyl ring of the coordinated phosphinite. Finally, the bis(diphenylphosphine)calix[4]arene ligand (10) readily coordinated the Mo(CO)3L species, but the reaction did not go to completion, as evidenced by 1H NMR, even after a 5 day reaction time. Data suggest that the product is similar to that observed for 12 and 14, but the incomplete reaction complicated attempts to obtain pure material and prohibited definitive assignment of the coordination array.     

硝基苯加氢合成对氨基酚用负载铂催化剂的制备

 用甲醛还原沉积法制备了活性炭负载的铂催化剂（Pt／AC）和不\r\n同载体负载的铂催化剂，并考察了催化剂对硝基苯加氢制备对氨基酚反\r\n应的催化性能．结果表明，还原Pt（Ⅳ）的甲醛用量是影响催化剂性能\r\n的关键因素，甲醛必须过量而且存在一个最佳值．增加催化剂的铂负载\r\n量，不能有效提高加氢反应速度，反而易降低对氨基酚选择性；低铂负\r\n载量催化剂具有较高的活性、选择性及稳定性．XPS和TEM表征结果表明\r\n，金属铂集中分布于活性炭颗粒外部，其颗粒大小介于2～12nm间．炭\r\n载体催化剂的活性和选择性明显高于金属氧化物载体催化剂．掺入适量\r\n的Mg可显著提高Pt／AC催化剂的活性和选择性．     

基于粒子滤波和人工势场法的放射源搜寻方法

针对放射源搜寻过程中难度大、定位精度低等问题，提出了一种适用于移动机器人的自主寻源方法。该方法利用移动机器人搭载辐射探测器采集的剂量计数值，根据γ射线的衰减规律建立辐射衰减模型；在机器人前进的过程中利用粒子滤波算法对放射源的参数进行实时估计；采用高斯分布函数对重采样后的粒子进行自适应更新，保证重采样后的粒子具有多样性；根据辐射环境创建机器人路径规划模型，采用人工势场法规划机器人的自主寻源路径。实验在Matlab下进行了仿真验证，结果表明，该方法在有遮挡环境下能够搜寻到未知的单点源，同时自适应更新能够提高算法的稳定性，缩小寻源误差。     

Base-mediated reaction of vinyl bromides with aryl azides: one-pot synthesis of 1,5-disubstituted 1,2,3-triazoles

A one-pot base-mediated reaction of azides and β- or α-vinyl bromides has been reported. The effects of bases and solvents have been investigated in the process. A variety of 1,5-disubstituted triazoles were prepared in low to good yields. Further studies reveal that the corresponding alkynes were produced as intermediates via elimination reaction. Under the same reaction conditions, the reactions of alkyl alkynes with phenyl azide would give 1,5-disubstituted 1,2,3-triazoles.     

One-pot synthesis of CoO–ZnO/rGO supported on Ni foam for high-performance hybrid supercapacitor with greatly enhanced cycling stability

The high specific capacitance along with good cycling stability are crucial for practical applications of supercapacitors,which always demands high-performance and stable electrode materials.In this work,we report a series of ternary composites of CoO-ZnO with different fractions of reduced graphene oxide(rGO) synthesized by in-situ growth on nickel foam,named as CZG-1,2 and 3,respectively.This sort of binder-free electrodes presents excellent electrochemical properties as well as large capacitance due to their low electrical resistance and high oxygen vacancies.Particularly,the sample of CZG-2(CoO-ZnO/rGO 20 mg) in a nanoreticular structure shows the best electrochemical performance with a maximum specific capacitance of 1951.8 F/g(216.9 mAh/g) at a current intensity of 1 A/g.The CZG-2-based hybrid supercapacitor delivers a high energy density up to 45.9 Wh/kg at a high power density of 800 W/kg,and kept the capacitance retention of 90.1% over 5000 charge-discharge cycles.     

Laser frequency stabilization based on Sagnac interferometric spectroscopy

A simple method based on Sagnac interferometric spectroscopy (SIS) is applied for frequency stabilization of diode lasers. Sagnac interferometric spectra of rubidium vapor are investigated both theoretically and experimentally. The interference signal at the output of the Sagnac interferometer displays a sharp dispersion feature near the atomic resonance. This dispersion curve is used as the feedback error signal to stabilize the laser frequency. Linewidth of a diode laser is stabilized down to 1 MHz by this modulation-free method.