水合碱中钙、镁含量的快速分析法

探讨了水合碱中钙、镁含量的快速分析方法——沉淀过滤分离后EDTA配位滴定法,在溶液酸性条件下,分别加入铬黑T、钙指示剂,用EDTA标准溶液滴定至纯蓝色,经计算得出钙、镁含量。分析中需加入三乙醇胺掩蔽,以消除铁等金属离子的干扰。该方法准确、可靠,能够满足生产监控的需要。

(±)-─氧化吲哚基乙酸的拆分及其绝对构型的确定

（±）－１．３－二甲基－５－甲氧基氧化吲哚基－３－乙酸（Ⅲ）是合成天然囊毒碱的关键中间体，以水作溶剂利用马钱子碱拆分可得光学纯对映体（－）－１，３－二甲基－５－甲氧基氧化吲哚基－３－乙酸（（ⅢＡ）和（＋）－１，３－二甲基－５－甲氧基氧化吲哚基－３－乙酸（ⅢＢ）并确定了对映体（ⅢＡ）和（ⅢＢ）的绝对构型，其手性碳原子绝对构型分别为和Ｓ和Ｒ．

Synthesis and Structural Characterization of [Mn(sapn)(H_2O)_2]Br

The crystal structure of the title compound [Mn(sapn)(H2O)2]Br (H2sapn = N,N?bis-(salicylidene)-1,3-diaminopropane) with formula C17H18N2O4MnBr and Mr = 449.18 has been determined by X-ray diffraction. The crystal is triclinic with space group P , a = 7.777(1), b = 10.459(2), c = 11.96(3), = 78.22(1), =75.16(8), = 86.80(5)? V = 919(3)3, Dc = 1.631g/cm3, F(000) = 456, = 2.917 cm-1 and Z = 2, with R = 0.0428 and wR = 0.1092 for 2427 reflections (I > 2s(I)). Two nitrogen and two oxygen atoms from the sapn group chelate to the MnⅢ ion, forming a distorted octahedral geometry together with two coordinated water molecules. A bromide anion exists outside as a counter ion.

Supercritical Water as a Reaction Medium for Nitrogen-Containing Heterocycles

Supercritical water has been focused on as an environmentally attractive reaction media, in which organic materials can be decomposed into smaller molecules. The reaction behavior of pyrrole as a simple model compound of nonbasic nitrogen compounds found in petroleum residua was studied in supercritical water with a batch type reactor. The reaction was carried out at temperatures of 698-748 K and at various pressures under an argon atmosphere. The chemical species in the aqueous products were identified by GCMS （gas chromatography mass spectrometry） and quantified using GC-FID （gas chromatography flame ionization detector）. The effect of temperature and reaction time on the conversion process of pyrrole is presented. Under supercritical water conditions, pyrrole underwent successful decomposition in water into its derived compounds. The conversion of pyrrole could approach 81.12 wt% at 723 K and 40 MPa within 240 min of reaction time. The decomposition process was accelerated with the existence of water at the same temperature. Ultimate analysis of solid products was also conducted using a CHN analyzer. The process investigated in this study may form the basis for an efficient method of nitrogen compound decomposition in future.

Comparative proteome analysis of alkaliphilic Bacillus sp.N16-5 grown on different carbon sources

To determine the impact of carbohydrates on the metabolic pathway in alkaliphiles, proteomes were obtained from cultures containing different carbohydrates and were resolved on two-dimensional gel electrophoresis (2-DE). The proteomes were compared to determine differentially expressed proteins. A novel alkaliphilic bacterium (alkaliphilic Bacillus sp. N16-5 isolated from Wudunur Soda Lake, China) was isolated in media with five different carbon sources (glucose, mannose, galactose, arabinose, and xylose). Comparative proteome analysis identified 61 differentially expressed proteins, which were mainly involved in carbohydrate metabolism, amino acid transport, and metabolism, as well as energy production and conversion. The comparison was based on the draft genome sequence of strain N16-5. The abundance of enzymes involved in central metabolism was significantly changed when exposed to various carbohydrates. Notably, catabolite control protein A (CcpA) was up-regulated under all carbon sources compared with glucose. In addition, pentose exhibited a stronger effect than hexose in CcpA-mediated carbon catabolite repression. These results provided a fundamental understanding of carbohydrate metabolism in alkaliphiles.

A hybrid carboxylate-water decamer with a discrete octameric water moiety self-assembled in a 2D copper(Ⅱ) coordination polymer

An octameric water moiety which consists of a chairlike water hexamer and two pendent water molecules in the 1,4-diaxial positions and shows a similar structure to the hydrocarbon （lr,4r）-1,4-dimethylcyclohexane, is unambiguously trapped in a 2D Cu（II） mixed-ligand coordination polymer, {[Cu2（bpp）2（HzO）2（bpda）2]＇6H2O}n （1） （bpp = 1,3-bis（4-pyridyl）propane and H2bpda = 2,2＇-biphenyldicarboxylic acid）. The water octamer can be extended into a hybrid carboxylate-water decamer when carboxylic oxygen atoms from bpda2- are involved. Interestingly, the present hybrid decamer bears a similar structural topology to a butterfly （H2O）10 cluster. The reversible dehydration/hydration of 1 is determined by X-ray powder diffraction studies.

Interfacial assembly of a series of Cu(Ⅱ)-coordinated Schiff bases complexes:Orderly nanostructures and supramolecular chirality

Four achiral Cu(Ⅱ)-coordinated Schiff bases complexes containing aromatic structures were synthesized and their supramolecular assemblies at the air/water interface were investigated.All the compounds could be spread on water surface although they have no alkyl chains.The Schiff base complex molecules with naphthyl groups tended to form J-aggregate in the Langmuir-Blodgett(LB) films transferred from water surface.By investigation of atomic force microscopy,a multilayer film or three-dimensional structures were observed.It was interesting to note that the LB films of achiral compound Cu-NA with naphthyl segment and without methyl groups transferred from water surface showed chirality.The supramolecular chirality in the present LB films was suggested to be due to a cooperative stereoregular-stacking of the functional groups in a helical sense.This research work provides a helpful clue for regulating the nanostructures and supramolecular chiral assembly in organized films.