Mirror Symmetry Breaking of cis-[Ni(NCS)_2tren]: Special Chiral Conformations of Chelate Rings

为了探究CIS-[nI(nCS)2TrEn][TrEn:三(2-氨基乙基)胺]的手性来源,本文采用单晶X射线衍射、溶液紫外-可见-近红外(uV-VIS-nIr)光谱、固体紫外圆二色(Cd)光谱和粉末X射线衍射(Xrd)等对CIS-[nI(nCS)2TrEn]的一对手性晶体进行了表征.研究结果表明:该手性晶体由结晶过程中的镜面对称性破缺而形成;三角架型配体TrEn配位后的特殊手性构象(δδλ,λλδ)是CIS-[nI(nCS)2TrEn]的主要手性来源.络合物固体紫外Cd谱所呈现的COTTOn效应可能来自其螯环手性构象以及手性金属中心对nCS-配体的π-π*跃迁和荷移跃迁生色团的手性微扰.对20批次合成产物进行固体Cd检测的统计结果表明:它们的对映体过量(EE)值在39%-100%之间.In order to explore the chiral origin of cis-[Ni(NCS)2tren] [tren: tris(2-aminoethyl) amine], a pair of chiral crystals of cis-[Ni(NCS)2tren] was characterized by X-ray single crystal structural analysis, solution UV-Vis-near infrared (NIR) spectroscopy, solid state UV-circular dichiroism (CD), and powder X-ray diffraction (XRD) spectra.The results indicated that the chiral crystals of cis-[Ni(NCS)2tren] were obtained by mirror symmetry-breaking crystallization, and the special chiral ring conformations (δδλ, λλδ) of the coordinated tripod-type tren ligands are responsible for the chiral origin of cis-[Ni(NCS)2tren].The Cotton effects of Ni(II) complexes in the solid-state UV-CD spectra are presumably attributed to the π-π* and charge-transfer chromophores of the NCS- ligands by the chiral perturbation of the helical ring conformations and metal-centered chirality.According to the statistical results of solid-state CD spectra of cis-[Ni(NCS)2tren] for twenty batch syntheses, their enantiomeric excess (ee) values are between 39% and 100%.国家自然科学基金(20773098;20973136)资助项目---

cis-[Ni(NCS)_2tren]的镜面对称性破缺: 螯环的特殊手性构象

为了探究cis-[Ni(NCS)2tren][tren:三(2-氨基乙基)胺]的手性来源,本文采用单晶X射线衍射、溶液紫外-可见-近红外(UV-Vis-NIR)光谱、固体紫外圆二色(CD)光谱和粉末X射线衍射(XRD)等对cis-[Ni(NCS)2tren]的一对手性晶体进行了表征.研究结果表明:该手性晶体由结晶过程中的镜面对称性破缺而形成;三角架型配体tren配位后的特殊手性构象(δδλ,λλδ)是cis-[Ni(NCS)2tren]的主要手性来源.络合物固体紫外CD谱所呈现的Cotton效应可能来自其螯环手性构象以及手性金属中心对NCS-配体的π-π*跃迁和荷移跃迁生色团的手性微扰.对20批次合成产物进行固体CD检测的统计结果表明:它们的对映体过量(ee)值在39%-100%之间

输出功率稳定的封离型CO_2激光器

一、前言 随着激光研究工作的进展,需要对器件的增益、功率和镜片的反射、透射系数进行较准确的测定,而输出功率稳定的激光器是进行这些工作不可缺少的条件,这一类型的激光器在国民经济中也有一定的用途。 用九五硬料玻璃制的激光器,我们得到了一分钟内功率漂移约为±1％,半小时内功率漂移为±3％。石英玻璃制激光器一分钟内功率漂移小±0.5％,半小时内功率漂移小于±1％。后者已间断工作两年零九个月,效果良好

激光辐照下蒸气羽的形象及其成长

把CO_2激光器连续输出功率约70瓦的激光束,经焦距138毫米反射镜聚焦于靶材上,功率密度约3×10~4瓦/厘米~2;利用平晶错位干涉仪观察靶前蒸气羽的现象,平晶楔角为6″及20″;用高速摄影机连拍蒸

Electrocatalytic Oxidation and Degration of Active Red X-3B by Nanotubes Catalytic Electrodes

将催化裂解法制得的碳纳米管,先经稀酸分散和空气热氧化处理,再按一定比例加入酚醛树脂,高速球磨处理后,将碳纳米管电极片热压成型.其表面形貌由扫描电镜(SEM)表征.以碳纳米管电催化电极作阳极,不锈钢片为阴极,降解处理含活性艳红X-3B模拟印染废水.考察了电流密度、电解质浓度、体系反应温度及pH值对废水降解效率的影响.结果表明:酸性条件下有利于染料有机物降解反应的进行,于常温下即可作高效降解处理.The catalytic splitting decomposition of carbon nanotubes isprocessed by dispersing with dilute nitric acid and thermal oxidation. Then well-proportionedphenolic resin is mixed in the carbon nanotubes. Then, the carbon nanotubesare made into electrodes by hot-press molding after the process of milling with high speed. The surface of the carbon nanotubes electrodes is analyzed by SEM. Active red X-3B simulated waster water is disposed by carbon nanotubes catalyticelectrode (anode) and stainless steel(cathode). The influencing factors of degradation by current density, concentrationof electrolyte, systemtemperature and pH are investigated. The experimental results indicated that acidiccondition is propitious tothe degradationreaction of organicdyestuff and wastewater can be disposed at normal temperature.作者联系地址：上海大学理学院化学系,上海大学理学院化学系,上海大学理学院化学系,上海大学理学院化学系 上海200444 ,上海200444 ,上海200444 ,上海200444Author's Address: *, CAO Wei-min, SHI Li-yiDepartmentof Chemistry, ShanghaiUniversity, Shanghai200444,Chin

Applications of New Activated Carbon Meterials in the Electric Double-layer Capacitor

　以椰壳为原料,利用特定的物理 化学方法在一定条件下制得双电层电容器活性炭电极材料.实验表明,该活性炭经压制成型后制作的双电层电容器,具有大的比电容,文中同时研究了酸处理、二次活化以及电极冷压成型方法对电极性能的影响.A new type activated carbon whose precursor was coconut shell could be obtained using specific physics-chemistry activation, and the activated carbon was applied as the material of electrode in EDLC(electrical double-layer capacitor),which had a large specific capacitance,and could charge and discharged in some large currents. Carbon dioxide and acid were used to modify carbon,and the effects of post-treatment on surface area and pore volume were investigated. A moulding method which has influence on some properties of carbon electrode with PTFE additive was researched in the paper.作者联系地址：上海大学环境与化学工程学院,上海大学理学院化学系,上海大学理学院化学系,上海大学理学院化学系,上海大学理学院化学系,上海大学理学院化学系,上海大学理学院化学系 上海200072 ,上海200436 ,上海200436 ,上海200436 ,上海200436 ,上海200436 ,上海200436Author's Address: 1, JIANG Hua~2,FANG Jian-hui~*2,SHI Li-yi~2,YIN Ren-he~2,WEN Yi~2, LIU Ji-quan~2 1.School of Environmental and Chemical Engineering,Shanghai University,Shanghai 200072,China, 2. Department of Chemistry, College of Sciences, Shanghai University,Shanghai 200436,Chin

人为气溶胶排放导致最近80年东亚夏季风在过去四个世纪以来空前减弱

亚洲夏季风(Asian Summer Monsoon, ASM)对亚洲数十亿人口的生存、亚洲生态系统和生物多样性的分布、以及农业生产(粮食安全)和工业活动影响严重。因此了解ASM过去时空变化及其动力学过程对陆地生态系统、水资源、森林和景观研究至关重要。近几十年,器测记录显示以降水量为代表的ASM强度一直在减弱,但这一减弱趋势的起始时间和动力学过程尚不清楚。为此,第一次集成了 ASM西部-中部边缘带10个对降水敏感的树木年轮宽度年表,重建了公元1566年以来反映ASM强度变化的降水序列。重建结果不仅捕捉到了 ASM过去4个世纪以来强弱变化历史,也反映出历史上蝗灾与弱季风的关联。特别是发现了最近80年具有过去448年中前所未有的、最为强烈的、显著且持续时间最长的ASM强度减弱趋势。这一减弱趋势与在温室效应影响下ASM本该增强的预期大相庭径。耦合气候模型实验表明,北半球人为硫酸盐气溶胶排放的逐渐增加,对ASM减弱起了决定性作用