W／O型微乳液中超氧化物阴离子的产生——微环境中SOD酶活性测定方法 …

分别在水溶液中和W／O型CTAB／正戊醇／异辛烷／水微乳液体系中研究了测定SOD酶活性的邻苯三酚法,发现在反向微乳液中,"小水池"的低介电常数和pH抑制了底物超氧化物阴离子O2-·的产生．只有提高外加缓冲液的pH或"小水池"的水化度,才能得到所需浓度的O2-·,从而初步解决了在微乳液中SOD作用底物的产生问题,为在微乳液中准确测定SOD酶活性创造了条件．     

Delocalization corrections to the strictly localized molecular orbitals: A linearized SCF approximation

An explicit formula is derived for calculating the delocalization corrections (tails) to be added to the strictly localized bond orbitals. It was obtained by solving analytically the SCF problem for the interbond interactions in a linearized approximation. The model calculations at the CNDO/2 level show that this simple approach is sufficient to account for the molecular conformations.     

植物油的质谱分析：1.蓖麻油

运用一种植物油的系统分析方法测定蓖麻油的精细组分，这包括皂化，ＢＦ３－ＭｅＯＨ甲基化，ＧＣ－ＣＩＭＳ法测定脂肪酸碳链长度和不饱和度，ＡＭＰ衍生化，ＧＣ－ＥＩＭＳ测定不饱和脂肪酸的双链位置，分析了蓖麻油的十一种脂肪酸组分，有五个为未知组分，并测定了其中三个组分的双链位置。     

NixB/沸石催化剂的分散性和反应性

用晶内形成法制备了Ni_xB/沸石催化剂,用饱和氢化学吸附法结合TEM方法考察了负载金属的分散性,并研究了其己环烷脱氢反应性。结果表明,Ni_xB/沸石样品上负载金属的分散性高,金属粒径分布也相对集中;金属负载量、载体结构和性质以及Ni_xB的制备条件对负载金属的分散性有明显影响。Ni_xB/沸石样品呈现较好的环己烷脱氢反应性。     

Asymmetric synthesis of heteroorganic analogs of natural products. 6. (S)-α-amino-ω-phosphonocarboxylic acids

Alkylation, by -haloalkylphosphonates, of the Ni(II) complex of the Schiff base formed from glycine and (S)-2-N-(N¹-benzylprolyl)-o-aminobenzophenone has been used for the asymmetric synthesis of (S)-2-amino-4-phosphonobutyric and (S)-2-amino-5-phosphonovaleric acids.Institute of Bioorganic Chemistry and Oil Chemistry, Ukrainian Academy of Sciences, 250800 Kiev. A. N. Nesmeyanov Institute of Organometallic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 397–402, February, 1992.     

Facile polyethylene glycol (PEG-400) promoted synthesis of β-ketosulfones

An efficient and convenient synthesis of β-ketosulfones is described. Reaction of an α-haloketone with sodium alkyl/aryl sulphinate yields the corresponding β-ketosulfone promoted by polyethylene glycol (PEG-400) as an efficient reaction medium.     

KF/Al~2O~3/PEG 4000(FAP)存在下氯仿的Michael加成反应

在KF/Al~2O~3/PEG4000(FAP)存在下,氯仿可与α,β-不饱和羰基化合物进行Michael加成反应,得到中等产率的三氯甲基化合物。     

Solubility Enhancement of Low Soluble Biologically Active Compounds by β-Cyclodextrin and Dimethyl-β-cyclodextrin

The solubility enhancement of triflumizole by complexation with -cyclodextrin and with dimethyl--cyclodextrin is compared with respect to the different physico-chemical properties of the host molecules. Although the inclusion reaction constants are rather similar for both complexation reactions, a completely different temperature dependence of the host-guest interaction is observed, which indicates a change of the reaction mechanisms. Moreover, the influence of ethanol as cosolvent is studied.     

New Photoluminescence Phenomena of Ge／SiO2 Glass Synthesized by Sol-gel Method

New Ge/SiO2 glasses have been synthesized by heating the GeO2/SiO2 dry gels under H2 gas at 700℃. The resulting fluorescence spectra show that this kind of Ge/SiO2 glasses emit strong photoluminescence at 392 nm (3.12 eV), medium strong photoluminescence at 600 nm (2.05 eV) and weak photoluminescence at 770 nm (1.60 eV) respectively. Possible photoluminescence mechanisms are also discussed based on the results of X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS).     

All-Solid-State PVC Membrane Ag+-Selective Electrodes Based on Diaza-18-Crown-6 Compounds

Two diaza-crown ether compounds were synthesized and evaluated as Ag⁺-selective carriers in polyvinylchloride (PVC) membrane electrodes of solid-state type. The all-solid-state PVC membrane electrode based on N,N-Dibenzyl-dibenzo-diaza-18-crown-6 exhibited a super-Nernstian response (75±10mV per decade) over the concentration range of 1×10^–1 to 7×10^–6M of Ag⁺ ion and a detection limit of 3×10^–6M, at a wide range of pH (pH 4–7). The response time of the electrode was fast (less than 10s), and it can be used for three months without any significant deviation in potential. The proposed all-solid-state PVC membrane electrodes revealed high selectivity toward Ag⁺ ion with respect to alkali, alkaline earth, heavy and transition metal ions. A flow-through cell of all-solid-state PVC membrane Ag⁺-selective electrode based on N,N-Dibenzyl-dibenzo-diaza-18-crown-6 has also been prepared and applied for flow-injection analysis of Ag⁺ ion in solution.