Synthesis, structure and physical properties of Ru ferrites: BaMRu5O11 (M=Li and Cu) and BaM′2Ru4O11 (M′=Mn, Fe and Co)

The synthesis, structure, and physical properties of five R-type Ru ferrites with chemical formula BaMRu₅O₁₁ (M=Li and Cu) and BaM′₂Ru₄O₁₁ (M′=Mn, Fe and Co) are reported. All the ferrites crystallize in space group P6₃/mmc and consist of layers of edge sharing octahedra interconnected by pairs of face sharing octahedra and isolated trigonal bipyramids. For M=Li and Cu, the ferrites are paramagnetic metals with the M atoms found on the trigonal bipyramid sites exclusively. For M′=Mn, Fe and Co, the ferrites are soft ferromagnetic metals. For M′=Mn, the Mn atoms are mixed randomly with Ru atoms on different sites. The magnetic structure for BaMn₂Ru₄O₁₁ is reported.     

网胰藻Hydroclathrus clathratus的化学成分研究

报道从中国南海网胰藻Hydroclathrus clathratus中分离得到3个单体化合物,经过MS,IR,1HNMR,13CNMR(DEPT),HMQC和HMBC等波谱技术鉴定为:(6R,7aS)-6-羟基-4,4,7a-三甲基-2,4,5,6,7,7a-六氢苯并呋喃-2-酮(1),1-(2-脱氧-β-D-呋喃核糖)-5-甲基-1,2,3,4-四氢嘧啶-2,4-二酮(2),尿嘧啶(3),并通过X射线单晶衍射实验确定化合物1的立体结构,其中化合物1是首次从自然界中分离得到.     

Eu3+/Tb3+和Eu3+/Pr3+共掺杂P(MMA-co-St)的荧光性能的研究

将不同荧光性能的铽(Tb)、镨(Pr)离子分别与铕(Eu)离子混合，以三异丙氧基稀土的形式掺杂P(MMA-CO-St)共聚物，研究Eu^3 ／Tb^3 和Eu^3 ／pr^3 共掺杂P(MMA-CO-St)的荧光性能的变化情况．结果表明，Eu^3 ／Tb^3 掺杂的P(MMA-CO-St)中，Tb^3 作为能量给予体，Eu^3 作为能量接受体，能量转移的结果使Eu^3 特征荧光显增强；Eu^3 ／pr^3 掺杂的P(MMA-CO-St)中，Eu^3 的能量向pr^3 转移，致使Eu^3 的特征荧光猝灭，pr^3 的荧光略为增强．     

Pentacyclic triterpenes from <Emphasis Type="Italic">Sarcostemma clausum</Emphasis>

A homologous series of alkanoic acid (C₂–C₅) esters of germanicol was isolated from the methanolic extract of Sarcostemma clausum, of which germanicol-3-propionate and 3-pentanoate have not been previously described in the literature. In addition, taraxasterol, multiflorenol, and bauerenol were also isolated for the first time from the genus Sarcostemma. Structures were elucidated by chemical and spectroscopic methods (NMR, IR, SM) and by comparison with literature data.Published in Khimiya Prirodnykh Soedinenii, No. 6 pp. 464–466, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

LB膜诱导Ba(NO3)2晶体取向生长

In this work, Ba(NO₃)₂ crystals with single crystal face were induced by using the the method of bio-mimetic mineralization and double LB films of behenic acid (BA) as the template. The crystals were characterized by Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). The crystals were observed in regular square shape with uniform size about 5～8 μm by SEM, and they were found by XRD to grow along the (111) plane. From these experiments, we can conclude that the good selection of the (111) crystal face of Ba(NO₃)₂ is due to the electrostatic interactions , the match between this crystal face and the definite lattice structure of the LB films.     

Carbon-bromine cleavage by dimethyl sulfoxide: the key step of C(5) functionalization of push-pull 2-alkylidene-4-oxothiazolidine vinyl bromides

Push-pull 2-alkylidene-4-oxothiazolidine vinyl bromides undergo efficient C(5) functionalization through DMSO-assisted carbon-bromine cleavage, followed by a bromine transfer-substitution (or elimination) sequence. A mechanism for this novel transformation is proposed.     

Degradation of ²-O-4 lignin model and related compounds by the ascomyceteChrysonilia sitophila (TFB 27441 strain)

Growth of the ascomyceteChrysonilia sitophila during degradation of lignin model dimers and monomers was compared to a glucose control. An inhibition of growth by Cα-carbonyl monomers and stimulation by β-O-4 lignin model and vanillyl alcohol were observed. A comparison of the degradation by this ascomycete with the basidiomycetePhanerochaete chrysosoporium showed similarities in relation to the type of degradation caused.     

1，2，4－三嗪类化合物的研究（ⅩⅫ）──咪唑并－（5，4－e）－1，2，4－三嗪衍生物的合成

１，２，４－三嗪类化合物的研究（ⅩⅫ）──咪唑并－（５，４－ｅ）－１，２，４－三嗪衍生物的合成沙耀武，蔡孟深（北京医科大学药学院，北京，１０００８３）关键词乙二脒腙，原甲酸三乙酯，１，２，４－三嗪，咪唑并－（５，４－ｅ）－１，２，４－三嗪天然碱基拮抗...