μ酰基铁硫配合物亲核取代反应的研究——若干三苯膦或三苯胂μ酰基铁硫配合物的合成及结构

μ-酰基铁硫配合物(μ-ArCO)(μ-RS)Fe_2(CO)_6和PPh_3在苯中迴流2小时, 或和AsPh_3在苯中迴流12小时可分别制得相应的单取代衍生物(μ-ArCO)(μ-RS)Fe_2(CO)_5 PPh_3(Ar=Ph, R=Et或B_u~t; Ar=p-ClC_6H_4, R=B_u~t)和(μ-ArCO)(μ-RS)Fe_2(CO)_5AsPh_3(Ar=Ph, R=Et或B_u~t).除用碳氢分析, IR和~1HNMR光谱表征了这五个新取代衍生物的结构外, 还测得一个代表物(μ-p-ClC_6H_4CO)(μ-B_u~t S)Fe_2(CO)_5 PPh_3的单晶结构. 该晶体属三斜晶系, 空间群P1. 晶胞参数a=1.0536(2), b=1.1714(4), c=1.4841(8) nm; α=98.47(4), β=102.70(4), γ=105.78(3)°; V=1.6771 nm; Z=2; D_C=1.468 g·cm~(-3). 最终偏离因子R=0.065.     

Determination of V(V), Nb(V) and Ta(V) as their 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol chelates by reversed-phase HPLC

This paper reports the separation and determination of V(V), Nb(V) and Ta(V) by RP-HPLC using 5-Br-PADAP as a precolumn derivatizing reagent. On C(18) column, the three metal chelates can be separated on a baseline in 9 min with the mobile phase of methanol-water (59:41, v/v) containing tartaric acid (0.2%) and acetate buffer (pH 3.5, 10 mM). The detection limits of V(V), Nb(V) and Ta(V) are 0.13 ppb, 0.22 ppb and 1.79 ppb, respectively when S/N is 3. This method is simple and rapid, and has been used in mineral analysis with satisfactory results.     

CeO2—LnO1.5固溶体的表征及其甲烷催化燃烧性能

向CeO2中引入Ln3 离子后形成的CeO2－LnO1.5（Ln=La，Nd，Sm，Gd）固溶体（n（Ce）：n（Ln）=1：1）是一种无贵金属的新型高效甲烷燃烧催化剂．比表面、XRD、Raman、TEM等分析证实，这类固溶体具有部分畸变的萤石结构，Ln3 进入晶格后诱发的结构变化使得团溶体的表面和本体能同时参与氧化还原反应．实验表明，该固态溶液体系是甲烷催化燃烧的良好催化剂．     

Novel fragmentation reaction of correolide

[reaction: see text] Pentacyclic triterpenoid natural product correolide (1) was converted to ketone 2 via ozonolysis. An unusual fragmentation reaction of ketone 2 with LiCl was discovered. This reaction is general among several similar substrates examined and appears to be specific for the correolide-type E-ring structure (ketone). A mechanism involving a retroaldol reaction, a nucleophilic opening of the epoxide, and a subsequent acetoxy elimination reaction was proposed.     

利用无水乙醇分解制备碳纳米管

利用CVD法高温分解无水乙醇,以分子筛（合成皂石）基体上的Fe颗粒为催化剂,制备出了管壁更薄、端部为开口结构的碳纳米管.本实验制备出的碳纳米管,相对于传统CVD方法制备出的碳纳米管,在实验条件控制稳定的情况下,管壁较直、缺陷较少、管内径较大.具有这样结构的碳纳米管在储氢等方面应具备更为优良的效果,从而有着潜在的应用前景.     

Immobilization of copper in organic-inorganic hybrid materials: a highly efficient and reusable catalyst for the Ullmann diaryl etherification

The immobilization of copper in organic-inorganic hybrid materials catalyzing the Ullmann reaction has been described. Phenols reacted with aryl iodides, aryl bromides and aryl chlorides smoothly in the presence of a 3-(2-aminoethylamino)propyl functionalized silica gel immobilized copper catalyst. The protocol involved the use of DMSO as the solvent, and potassium fluoride as the base. The reactions generated the corresponding cross-coupling products in good to excellent yields. Furthermore, the silica-supported copper could be recovered and recycled by a simple filtration of the reaction solution and used for 10 consecutive trials without loss of its reactivity.     

New disulfido molybdenum-manganese complexes exhibit facile addition of small molecules to the sulfur atoms

The reaction of Mn(2)(CO)(7)(mu-S2) (1) with [CpMo(CO)(3)](2) (Cp = C(5)H(5)) and [Cp*Mo(CO)(3)](2) (Cp* = C(5)(CH(3))(5)) yielded the new mixed-metal disulfide complexes CpMoMn(CO)(5)(mu-S2) (2) and Cp*MoMn(CO)(5)(mu-S2) (3) by a metal-metal exchange reaction. Compounds 2 and 3 both contain a bridging disulfido ligand lying perpendicular to the Mo-Mn bond. The bond distances are Mo-Mn = 2.8421(10) and 2.8914(5) A and S-S = 2.042(2) and 1.9973(10) A for 2 and 3, respectively. A tetranuclear metal side product CpMoMn(3)(CO)(13)(mu3-S)(mu4-S) (4) was also isolated from the reaction of 1 with [CpMo(CO)(3)](2). Compounds 2 and 3 react with CO to yield the dithiocarbonato complexes CpMoMn(CO)(5)[mu-SC(=O)S] (5) and Cp*MoMn(CO)(5)[mu-SC(=O)S] (6) by insertion of CO into the S-S bond. Similarly, tert-butylisocyanide was inserted into the S-S bond of 2 and 3 to yield the complexes CpMoMn(CO)(5)[mu-S(C=NBu(t))S] (7) and Cp*MoMn(CO)(5)[mu-S(C=NBu(t))S] (8), respectively. Ethylene and dimethylacetylene dicarboxylate also inserted into the S-S bond of 2 and 3 at room temperature to yield the ethanedithiolato ligand bridged complexes CpMoMn(CO)(5)(mu-SCH(2)CH(2)S) (9), Cp*MoMn(CO)(5)(mu-SCH(2)CH(2)S) (10), CpMoMn(CO)(5)[mu-SC(CO(2)Me)=C(CO(2)Me)S] (11), and Cp*MoMn(CO)(5)[mu-SC(CO(2)Me)=C(CO(2)Me)S] (12). Allene was found to insert into the S-S bond of 2 by using one of its two double bonds to yield the complex CpMoMn(CO)(5)[mu-SCH(2)C(=CH(2))S] (13). The molecular structures of the new complexes 2-7 and 9-13 were established by single-crystal X-ray diffraction analyses.