负载稀土型酸活化膨润土的酯化催化活性

负载稀土型酸活化膨润土的酯化催化活性李永绣，冯天泽，胡平贵，何小彬，辜子英，廖荣辉（南昌大学化学系南昌３３００４７）关键词稀土，膨润土，催化酯化可用稀土、膨润土单独作酯化催化剂，但活性不高［１～３］。本文将稀土用离子交换的方法负载到酸活化膨润土中，寻...     

Chemistry of O-Benzoquinones and Masked O-Benzoquinones I. Diels-Alder Reactions of O-Benzoquinones with Dimethyl Acetylenedicarboxylate and Phenylacetylene

Diels-Alder reactions of six o-benzoquinones with dimethyl acetylenedicarboxylate has been examined. The yields of adducts vary with the natures of the o-benzoquinones, 3,4-Di-n-propyl-(1c), 3,6-di-n-propyl (1d). 3. 4-diallyl-(1e) and 3, 6-diallyl-o-benzoquinone (1f) are found to give bicyclic a-diketones exclusively without the formation of 1,4-dioxine derivatives, the yields ranging from 20 to 70%. In the case of 4, 5-dimethoxy-o-benzoquinone, dimethyl 4, 5-dimethoxyphthalate is produced in 42% yield, presumably derived from the decomposition of the corresponding initially formed α-diketone. 3, 6-Di-n-propyl-4, 5-dimethoxy-o-benzoquinone deteriorates without addition to dimethyl acetylenedicarboxylate upon heating. The additions of o-benzoquinones 1c , 1d and 1f to phenylacetylene are also studied. The yields of adducts, α-diketones, range from 23% to 82%.     

Two—dimensional Network Crown Ether Complex.Synthesis and Crystal Structure of 18—Crown—6 Complex：[K（18—C—6）]2[Cd—（nmt）2]

The novel complex [K(18-C-6)]2[Cd(mnt)2][18-C-6-18-crown-6,nmt=1,2-dicyanoethene-1,2-dithiolate,C2S2-(CN)2^2-] was synthesized and characterized by elemental analysis,IR spectrum and X-ray diffraction analysis.The complex displays two-dimensional network structure of [K(18-C-6)] complex segments and [Cd(nmt)2] complex segment bridged by S-K-S,S-K-N and N-K-N interactions between adjacent[K(18-C-6)] and [Cd(mnt)2]units.     

Recycling Chiral Organocatalyst （4S）-Phenoxy-（S）-proline for Direct Asymmetric Aldol Reaction in Ionic Liquid （bmim）PF6

Room temperature ionic liquid (bmim)PF6 was evaluated for recycling an organocatalyst (4S)-phenoxy-(S)-proline for direct asymmetric aldol reactions. The desired aldol products were obtained with good yields up to 93.2% and enantioselectivities up to 88.5%, and isolation of the products by simple extraction allowed recycling the ionic liquid containing the immobilized catalyst in subsequent reactions without significant decrease of yields and enantioselectivities.     

含双二苯基膦甲烷铜(Ⅰ)配合物的研究进展

本文概述了含双二苯基膦甲烷铜(Ⅰ)配合物的化学进展,总结了配合物的合成方法:置换法、还原法、电化学方法和直接加成法,全面论述了双核、三核、多核和异核配合物的结构特征,探讨了该类配合物的重要荧光性质。     

Direct electrochemistry and enzymatic activity of hemoglobin in positively charged colloid Au nanoparticles and hemoglobin layer-by-layer self-assembly films

Alternate adsorption of positively charged colloid-Au nanoparticles (nano-Au⊕) and negatively charged hemoglobin (Hb) on L-cysteine (L-cys) modified gold electrode resulted in the assembly of {Hb/nano-Au⊕}n layer-by-layer films/L-cys modified gold electrode. The nano-Au⊕ was characterized by transmission electron micrograph (TEM) and microelectrophoresis. The modified electrode interface morphology was characterized by electrochemical impedance spectroscopy (EIS), atomic force mi- croscopy (AFM), cyclic voltammograms (CV) and chronoamperometry. Direct electron transfer between hemoglobin and gold electrodes was studied, and the apparent Michaelis-Menten constant ( km app) of the modified electrode was evaluated to be 0.10 mmol·L?1. Moreover, the higher activity of proteins in the nano-Au⊕ films could be retained compared with the electropolymerization membrane, since the pro- teins in nano-Au⊕ films retained their near-native structure. Direct electron transfer between hemoglo- bin and electrode and electrochemically catalyzed reduction of hydrogen peroxide on a modified elec- trode was studied, and the linear range was from 2.1×10-8 to 1.2 ×10?3 mol·L-1 (r = 0.994) with a detection limit of 1.1×10-8 mol·L-1 H2O2.     

Alkanethiolate self-assembled monolayers as functional spacers to resist protein adsorption upon Au-coated nerve microelectrode

Alkanethiolate self-assembled monolayers (SAMs) of varied chain lengths were adsorbed upon Au-coated nerve microelectrodes and employed as protein-resistant spacers. The microelectrode spiraled as a cuff type can be used for restoring motor function via electrical stimulation on the peripheral nerve system; however, an increase of electrode impedance might occur during implantation. In this work, a thin-film SAMs treatment upon Au/polyimide (PI) surface of the microelectrode provided a hydrophobic characteristic, which retarded protein adsorption at the initial stage and subsequent pileup (or thickening) process. The protein-resistant effect exhibited comparable SAMs of different chain lengths adsorbed upon Au/PI surfaces. The increase of electrode impedance as a function of protein deposition time was mainly correlated with the addition of reactance that was associated with the pileup thickness of the deposited protein. Particularly, the SAMs-modified surface was capable to detach a significant portion of the accumulated protein from the protein-deposited SAMs/Au/PI, whereas the protein-deposited layers exhibited firm adhesion upon Au/PI surface. It is therefore very promising to apply thin-film SAMs adsorbed upon Au-coated surface for bioinvasive devices that have the need of functional electrical stimulations or sensing nerve signals during chronic implantation.     

From D-glucose to biologically potent L-hexose derivatives: synthesis of alpha-L-iduronidase fluorogenic detector and the disaccharide moieties of bleomycin A2 and heparan sulfate

A novel and convenient route for the synthesis of biologically potent and rare L-hexose derivatives from D-glucose is described. Conversion of diacetone-alpha-D-glucose (14) into 1,2:3,5-di-O-isopropylidene-beta-L-idofuranose (19) was efficiently carried out in two steps. Orthogonal isopropylidene rearrangement of compound 19 led to 1,2:5,6-di-O-isopropylidene-beta-L-idofuranose (27), which underwent regioselective epimerization at the C3 position to give the L-talo- and 3-functionalized L-idofuranosyl derivatives. Hydrolysis of compound 19 under acidic conditions furnished 1,6-anhydro-beta-L-idopyranose (35) in excellent yield, which was successfully transformed into the corresponding L-allo, L-altro, L-gulo, and L-ido derivatives via regioselective benzylation, benzoylation, triflation and nucleophilic substitution as the key steps. Applications of these 1,6-anhydro-beta-L-hexopyranoses as valuable building blocks to the syntheses of 4-methylcoumarin-7-yl-alpha-L-iduronic acid and the disaccharide moieties of bleomycin A(2) as well as heparan sulfate are highlighted.     

CO2部分氧化乙烷制乙烯Pd—Cu／MoO3—SiO2催化剂的研究

用化学吸附－红外光谱、化学吸附－程序升温脱附（ＴＰＤ）和微型反应技术研究了Ｐｄ－Ｃｕ／ＭｏＯ３－ＳｉＯ２（ＭｏＳＯ）催化剂对ＣＯ２和乙烷的吸附活化和部分氧化反应性能．结果表明，乙烷以Ｃ—Ｈ键中的Ｈ吸附于ＭｏＳＯ载体表面ＭｏＯ键的端基氧上；Ｐｄ－Ｃｕ／ＭｏＳＯ催化剂对ＣＯ２有良好的化学吸附活化性能，ＣＯ２的吸附除有线式吸附态和剪式吸附态外，还有一种新的卧式吸附态；Ｐｄ－Ｃｕ／ＭｏＳＯ催化剂的晶格氧参与了化学反应．探讨了在Ｐｄ－Ｃｕ／ＭｏＳＯ催化剂上ＣＯ２的部分氧化乙烷反应机理     

Titrimetric determination of thiocyanate and thiosulphate ions by oxidation with iodine in alkaline solution

Thiocyanate (2.7-90 mug) and thiosulphate (4.5-90 mug) ions are oxidized by iodine in alkaline media to sulphate ions. After acidification, the excess of iodine is extracted into chloroform, and the iodide ions formed in the redox reaction subjected to an amplification reaction. Either a titrimetric or a spectrophotometric finish may be used. Each thiocyanate and thiosulphate ion results in the ultimate production of 19 and 24 iodine molecules, respectively.