氧化条件下NOx催化的甲烷均相部分氧化

考察了没有固体催化剂时NOx对甲烷气相氧化的促进作用.实验结果表明，即使在强氧化条件下（O2/CH4=5），NOx对甲烷部分氧化制一氧化碳仍然有明显的催化活性.在CH4-O2体系中加入0.005％～0.2％的NO后，反应温度可降低200-300 ℃.在反应产物中还可观察到甲醛和乙烯，通过改变反应条件可以控制它们的相对浓度.     

紫外线激活氚原子—制备氚标记单磷酸阿糖腺苷的研究

本文采用紫外线激活氚原子的方法,进行氚-氢同位素交换反应,制得氚标记单磷酸阿糖腺苷(9—~3H—mparaA)。产品的纯度是层析纯;放射性比活度16GBq.m mol~(-1);放射化学纯度92.0%。本法的优点是:交换反应温和、反应时间较短、不易破坏生物活性、引起的副产物少、产品分离和纯化较方便。     

Determination of aniline in silica gel sorbent by one-step in situ microwave-assisted desorption coupled to headspace solid-phase microextraction and GC-FID

Microwave-assisted desorption (MAD) coupled to in situ headspace solid-phase microextraction (HS-SPME) was first proposed as a possible alternative pretreatment of samples in absorbent collected from workplace monitoring. Aniline collected on silica gel was investigated. Under microwave irradiation, the aniline was desorbed from silica gel and directly absorbed onto the SPME fiber in the headspace. Having been sampled on the SPME fiber, and desorbed in the GC injection port, aniline was analyzed using a GC-FID system. Parameters that affect the proposed extraction efficiency, including the extraction media and its pH, the microwave irradiation power and the irradiation time as well as desorption parameters of the GC injector, were investigated. Experimental results revealed that the extraction of a 150-mg silica gel sample using a 0.8-ml aqueous solution (pH 12) and a PDMS/DVB fiber under medium-high-powered irradiation (345 W) for 3 min maximized the efficiency of extraction. Desorption of aniline from the SPME fiber was optimal at 230 °C held for 3 min. The detection limit was 0.09 ng. The proposed method provided a simple, fast, and organic solvent-free procedure to analyze aniline from a silica gel matrix.     

A new cucurbitane triterpenoid from Momordica charantia

One new cucurbitane-type triterpenoid saponin, 5b,19-epoxycucurbita-6,23-diene-3b,19,25-triol-3-O-b-D-allopyranoside (1), named momordicoside P was isolated from the fresh fruits of Momordica charantia. The structure of the saponin was elucidated byspectral methods, including 2D-NMR spectra.     

Ion size dominated 1D and 2D Salen lanthanide coordination complexes and their luminescence

Lewis acid/base addition between Ln(NO₃)₃ · 6H₂O (Ln = Pr, Nd, Sm, Eu, Tb and Lu) and H₂salen [H₂salen = N,N′-ethylenebis(salicylideneimine)] gives rise to an array of coordination polymeric structures. Crystal structural analysis reveals that Salen effectively functions as a bridging ligand in these compounds. The size of the lanthanide ions controls the structures of these Salen lanthanide complexes. Two representative structures with one dimensional and two dimensional topologies, viz. [Pr(H₂salen)(NO₃)₃(CH₃OH)₂]_n (1) and [Ln(H₂salen)_1.5(NO₃)₃]_n [Ln = Pr (2), Nd (3), Sm (4), Eu (5), Tb (6) and Lu (7)] are reported. Luminescent spectra of complexes 4 and 5 exhibit characteristic metal-centered emission lines. However, the characteristic luminescence of the terbium(III) ion is not observed either in solution or in the solid state of complex 6.     

Two Novel Oxamidato-bridged Tetranuclear Complexes M[Cu(PMoxd)]3(ClO4)2 (M=Mn, Ni, Cu(PMoxd)=N,N′-bis(pyridyl-methyl)-oxamidatocopper(II)): Syntheses, Spectra, Magnetic and Electrochemical Properties

Two novel oxamidato-bridged Mn[Cu(PMoxd)]₃(ClO₄)₂ (1) Ni[Cu(PMoxd)]₃(ClO₄)₂ (2) tetranuclear complexes were prepared and characterized by i.r., e.p.r., electronic spectra, cyclic voltammograms, and magnetic properties. The magnetic analysis was carried out by means of the theoretical expression of the magnetic susceptibility deduced from the spin Hamiltonian H=−2JS_M(S_Cu1+ S_Cu2 + S_Cu3) (M=Mn, Ni), leading to J=−20.4 cm⁻¹; −121.1 cm⁻¹ for complexes (1) and (2) respectively. Magnetic measurements indicate that the overall magnetic behavior of the tetranuclear species are antiferromagnetic.     

Crystal Structure of Complex Tris（4,4,4—trifluoro—1—pheny1—1,3—butanedione）（1,10—phenanthroline）Europium（Ⅲ）

The complex Eu(btfa)₃ (phen) (btfa=4,4,4‐trifluoro‐1‐phenyl‐1, 3‐butanedione, phen = 1,10‐phenanthroline) has been prepared and characterized by elemental analysis, IR and UV spectroscopies. The crystal and molecular structures of the complex have been determined by X‐ray diffraction analysis. It belongs to the monoclinic crystal system, space group P2₁/c with a = 0.9700(2) nm, b = 3.7450(5) nm, c = 1.0917(3) nm, β = 92.51(2)°, V = 3.962(1) nm⁵, Z = 4, D_c = 1.639 g/cm³, μ = 1.676 mm^?1, F(000) = 1936, R₁, = 0.0388, wR₂ = 0.0775. Structure analysis shows that the europium(III) ion is coordinated to six oxygen atoms of β‐diketonate anions and two nitrogen atoms of phenanthroline molecule. The coordination polyhedron is an approximate square antiprism.     

Electrocatalytic Oxidation of Dopamine by Ferrocene in Lipid Film Cast on a Glassy Carbon Electrode

ＩｎｔｒｏｄｕｃｔｉｏｎＤＡｉｓｏｎｅｏｆｅｓｓｅｎｔｉａｌｐａｒｔｉｃｉｐａｎｔｓｉｎｔｈｅｎｅｕｒｏ ｔｒａｎｓｍｉｓｓｉｏｎｐｒｏｃｅｓｓｉｎｍａｍｍａｌｉａｎｃｅｎｔｒａｌｎｅｒｖｏｕｓｓｙｓ ｔｅｍ .ＡｌｏｓｓｏｆＤＡ ｃｏｎｔａｉｎｉｎｇｎｅｕｒｏｎｓｍａｙｒｅｓｕｌｔｉｎｓｏｍｅｓｅｒｉｏｕｓｄｉｓｅａｓｅｓｕｃｈａｓＰａｒｋｉｎｓｏｎｉｓｍ .1Ｓｉｎｃｅｉｔｓｄｉｓｃｏｖ ｅｒｙｉｎｔｈｅ 195 0ｓ ,ＤＡｈａｓｂｅｅｎｏｆｉｎｔｅｒｅｓｔｔｏｎｅｕｒｏｓｃｉｅｎ ｔｉｓｔｓａｎｄｃｈｅｍ…     

Three New Triterpenoids from Lycopodium japonicum Thunb

Three new triterpenoids, (3β,8β,14α,21α)‐26,27‐dinoronocerane‐3,8,14,21‐tetrol ( 1 ), (3β,8β,14α,21β)‐26,27‐dinoronocerane‐3,8,14,21‐tetrol ( 2 ), and lycopodiin A ( 3 ), together with four known compounds, lycoclavanol ( 4 ), lycoclaninol ( 5 ), α‐onocerin ( 6 ), and 3‐epilycoclavanol ( 7 ), were isolated from Lycopodium japonicum Thunb (Lycopodiaceae). Their structures were established by means of spectroscopic analyses. Compounds 3 and 7 showed moderate antitumor activity. Compounds 4 and 6 exhibited acetylcholinesterase inhibition activity.     

Analysis of nonvolatile species in a complex matrix by headspace gas chromatography

This study developed a phase reaction conversion (PRC) headspace gas chromatographic (HS-GC) technique for the measurements of nonvolatile species in liquid or solid samples. The technique is demonstrated by the measurements of carbonate in aqueous carbonate solutions and in kraft pulp mill liquor samples. A very small amount of sulfuric acid (volume of 0.5 ml, concentration of 2 mol/l) is used to acidify a sample of less than 300 microl in volume and convert the dissolved carbonate into carbon dioxide (gas) in a sample vial (reactor) that is analyzed by thermal conductivity detection through a headspace sampler. The carbonate concentrations measured by PRC-HS-GC in seven kraft liquor samples agree very well with those measured using a coulometric and a titrametric method. Simultaneous analysis of multiple species was also conducted to demonstrate the versatility of the method. The present method is very simple, rapid, reliable, accurate, and fully automated. It can be applied to analyze other nonvolatile species in various industrial and environmental samples.