Heating, current drive and confinement regimes with the JET ICRH and lhcd systems

During its 1990 operation, 2 large RF systems were available on JET. The Ion Cyclotron Resonance Heating (ICRH) system was equipped with new beryllium screens and with feedback matching systems. Specific impurities generated by ICRH were reduced to negligible levels even in the most stringent H-mode conditions. A maximum power of 22 MW was coupled to L-mode plasmas. High quality H-modes (tau-E greater-than-or-equal-to 2.5 tau-EG) were achieved using dipole phasing. A new high confinement mode was discovered. It combines the properties of the H-mode regime to the low central diffusivities obtained by pellet injection. A value of n(d) tau-E T(i) = 7.8 x 10(20) m-3 s keV was obtained in this mode with T(e) approximately T(i) approximately 11 keV. In the L-mode regime, a regime, a record (140 kW) D-He-3 fusion power was generated with 10 - 14 MW of ICRH at the He-3 cyclotron frequency. Experiments were performed with the prototype launcher of the Lower Hybrid Current Drive (LHCD) systems with coupled power up to 1.6 MW with current drive efficiencies up to < n(e) > R I(CD)/P = 0.4 x 10(20) m-2 A/W. Fast electrons are driven by LHCD to tail temperatures of 100 keV with a hollow radial profile. Paradoxically, LHCD induces central heating particularly in combination with ICRH. Finally we present the first observations of the synergistic acceleration of fast electrons by Transit Time Magnetic Pumping (TTMP) (from ICRH) and Electron Landau Damping (ELD) (from LHCD). The synergism generates TTMP current drive even without phasing the ICRH antennae.

Electric and magnetic losses and gains in determining the sign of refractive index

Within the framework of classic electromagnetic theories, we have studied the sign of refractive index of optical medias with the emphases on the roles of the electric and magnetic losses and gains. Starting from the Maxwell equations for an isotropic and homogeneous media, we have derived the general form of the complex refractive index and its relation with the complex electric permittivity and magnetic permeability, i.e. n = root epsilon mu, in which the intrinsic electric and magnetic losses and gains are included as the imaginary parts of the complex permittivity and permeability, respectively, as epsilon = epsilon(r) + i(epsilon i) and mu = mu(r) + i mu(i). The electric and magnetic losses are present in all passive materials, which correspond, respectively, to the positive imaginary permittivity and permeability epsilon(i) > 0 and mu(i) > 0. The electric and magnetic gains are present in materials where external pumping sources enable the light to be amplified instead of attenuated, which correspond, respectively, to the negative imaginary permittivity and permeability epsilon(i) < 0 and mu(i) < 0. We have analyzed and determined uniquely the sign of the refractive index, for all possible combinations of the four parameters epsilon(r), mu(r), epsilon(i), and mu(i), in light of the relativistic causality. A causal solution requires that the wave impedance be positive Re {Z} > 0. We illustrate the results for all cases in tables of the sign of refractive index. One of the most important messages from the sign tables is that, apart from the well-known case where simultaneously epsilon < 0 and mu < 0, there are other possibilities for the refractive index to be negative n < 0, for example, for epsilon(r) < 0, mu(r) > 0, epsilon(i) > 0, and mu(i) > 0, the refractive index is negative n < 0 provided mu(i)/epsilon(i) > mu(r)/vertical bar epsilon(r)vertical bar. (c) 2006 Elsevier B.V. All rights reserved.

栽培牡丹起源研究

牡丹在中国被称作“花中之王”。我国不仅是全部野生牡丹的原产地，也是栽培牡丹最早的驯化地。野生牡丹共有8个种，分布于云南、四川、湖北、甘肃、陕西、山西、安徽、河南和西藏等9省区，因其具有很大的观赏和药用价值，而在中国和世界温带地区广泛栽培。本研究利用形态特征和4个核基因片段（三个Adh 基因和GPAT基因片断）的核苷酸序列变异对牡丹组的种间系统发育关系进行了分析，并对我国栽培牡丹四个品种群的101个代表品种的可能祖先进行了形态学鉴定和分子诊断标记研究。在此基础上，利用核编码叶绿体表达的GPAT基因的（大内含子）部分序列和叶绿体基因组的trnS – trnG 和 rpS16 – trnQ两个基因间隔区的DNA序列变异重建了栽培牡丹37个代表品种和26个野生居群间的谱系关系。结果表明：（1）GPAT基因树是迄今得到的分辨率最好，并具有很高自展值支持的牡丹组种间系统发育关系树;（2）GPAT基因树和形态学证据一致支持银屏牡丹（P. suffruticosa ssp. yinpingmudan）, 凤丹（P. ostii）, 紫斑牡丹（P. rockii）, 卵叶牡丹（P. qiui）, 和矮牡丹 （P. jishanensis） 参与了栽培牡丹的起源;（3）叶绿体DNA单倍型网络树（network）进一步证实上述5个祖先类群的4个（矮牡丹除外）可能参与了栽培牡丹的母系起源。37个品种的GPAT基因谱系和叶绿体DNA单倍型网络树一致表明银屏牡丹是栽培牡丹最主要的祖先，其次是紫斑牡丹、凤丹、和卵叶牡丹;（4）我们的分子证据不支持形态学证据关于矮牡丹是栽培牡丹最主要的野生祖先的推测;（5）形态学和分子诊断标记证据表明，101个品种中有65.35 % 的品种具有两个以上野生种的特征，18.81 % 品种同时具有 Eco R I (+) 和 InDel51(+)物种特异分子标记。对37个品种的GPAT基因谱系和叶绿体DNA谱系比较发现，其中35个可能是杂种起源。另外，对7个古代牡丹品种（据文献记载）的GPAT基因的不同克隆类型进行测序和谱系分析，结果表明其中4 个为杂种起源。上述证据充分表明杂交和（或）渗入杂交在牡栽培牡丹的起源和进化中发挥了重要作用。根据本研究的结果，结合现有的形态学数据、考古记录，以及有关牡丹栽培和驯化历史的记载，我们对栽培牡丹的起源和驯化历史总结如下。牡丹的栽培迄今有1,600 – 2,000年，栽培牡丹最迟起源于1，500年前。最初通过驯化和对突变的选择获得原始品种。由于牡丹品种可以通过无性和（或）有性方式进行繁殖，其后新的品种通过如下方式产生：（1）对突变的选择，（2）对栽培类型和野生种之间或栽培类型之间杂交和（或）渗入杂交产生的实生苗的选择。由于绝大部分（如果不是全部）早期的原始品种已绝灭，现有栽培牡丹是起源于各种人工和自然进化力共同作用的结果，其中包括多次驯化、人工选择、突变、杂交和渗入杂交等。据作者所知，栽培牡丹的这种 ‘compilospecies’ 起源和驯化模式是目前已研究过的主要栽培作物中未见报道的。 因此，本研究不仅为栽培牡丹的多系起源和驯化历史提供了可信的分子证据，同时也为利用单拷贝基因的内含子序列构建栽培作物及其近缘野生祖先间的种系发生关系提供了成功的例子。另外，本研究也为同时利用核和叶绿体基因组的非编码DNA序列研究杂交在栽培作物的起源和进化的中作用提供了成功的例子。

羚牛细胞色素J基因序列分析和系统进化研究

C应用聚合酶链式反应’NOP(分别扩增了羚牛Q绵羊Q山羊Q黄牛细胞色素R基因H并对其全序 列’##&"RS(进行了测定I其中羚牛细胞色素R基因序列属首次报道I通过对$种偶蹄类动物细胞 色素R基因序列差异分析和基于序列差异所构建的分子系统树H发现羚牛与羊亚科的动物亲缘关 系最近H与其他动物亲缘关系较远H表明将羚牛放入羊亚科较为合理I序列差异分析还表明羚牛约 在距今G""万年前’上新世(从牛类动物中分化出来H牛类分化时间约在L""万年前的中新世 ’T8*<5-5(

Optical properties of GaN wurtzite quantum wires

The electronic structure and optical properties of freestanding GaN wurtzite quantum wires are studied in the framework of six-band effective-mass envelope function theory. It is found that the electron states are either twofold or fourfold degenerate. There is a dark exciton effect when the radius R of GaN wurtzite quantum wires is in the range of [0.7, 10.9] nm. The linear polarization factors are calculated in three cases, the quantum confinement effect (finite long wire), the dielectric effect and both effects (infinitely long wire). It is found that the linear polarization factor of a finite long wire whose length is much less than the electromagnetic wavelength decreases as R increases, is very close to unity (0.979) at R = I nm, and changes from a positive value to a negative value around R = 4.1 nm. The linear polarization factor of the dielectric effect is 0.934, independent of radius, as long as the radius remains much less than the electromagnetic wavelength. The result for the two effects shows that the quantum confinement effect gives a correction to the dielectric effect result. It is found that the linear polarization factor of very long (treated approximately as infinitely long) quantum wires is in the range of [0.8, 1]. The linear polarization factors of the quantum confinement effect of CdSe wurtzite quantum wires are calculated for comparison. In the CdSe case, the linear polarization factor of R = I nm is 0.857, in agreement with the experimental results (Hu et al 2001 Science 292 2060). This value is much smaller than unity, unlike 0.979 in the GaN case, mainly due to the big spin-orbit splitting energy Delta(so) of CdSe material with wurtzite structure.

铕（II）等低价稀土离子在氧化物基质中光谱特征及其变化规律

近年来，围绕低价稀土离子开展的研究工作越来越多，尤其重视铕(II)、钐（II）和镱(II)的研究，以期获得短波可调固体激光晶体或高效率发光材料。由于4f~n到4f~(n-1)5d'组态的d-f跃迁是属于宇称允许的跃迁，所以它的发射要比4f~n壳层内的受迫电偶极跃迁强得多。这可以保证对泵浦的有效吸收，提高光泵效率。而4f~n组态内部的f-f锐线发射可以实现激光振荡，有利于提高储能，降低阀值。所以深入了解4f~n和 4f~(n-1)5d'体系在基质晶场中的行为以及基质环境对稀土离子发光特征的影响，对于寻找和设计新的激光和发光材料有着极为重要的意义。 本文从理论上讨论了晶场效应和化学键性质对铕(II)、钐(II)等稀土离子发光性质的影响。采用高温固相反应的方法合成了一系列铕(II)、钐(II)激活的氧化物基质荧光材料。结合光谱实验数据建立了晶格环境对铕(II)的 4f~65d'能级影响的表观模型和定量计算公式。为了研究4f~65d'激发态的性质，我们采用改进的Slater法计算了铕(II)和配体氧的有关轨道能量。利用静电晶场模型讨论了4f~65d'能带劈裂幅度(△E)与Eu-O键距(R)的关系，量子化学计算表明5d能级在晶场中的劈裂(△E)与R~5成反比。碱金属和碱七金属磷酸盐基质中铕的光谱数据证实了上述结论。在该基质中铕的4f~65d'能带的劈裂幅度随Eu-O键距增加而变小。在MeSO_4:Eu~(2+) (Me = Ca, Sr，Ba)中，随碱七金属离子半径增大，其发射和激发截止波长均有规律地向短波区移动。这是由于当铕(II)占据较大半径阳离子格位时，将受到较小的晶场影响。其体系的荧光寿命数据也证实了这一点。运用统计热力学原理讨论了4f~(n-1)5d'与 4f~n激发态能级的相对位置对低价稀土离子d-f和f-f跃迁发射的影响。在Ba_(1-x)Mg_(1+x)(SO_4):Eu~(2+)中，适当增大Mg~(2+)离子含量，线一带两种发射强度比R = I (f-f)/I(d-f) 明显增大。Ba_(0.4)Mg_(1.6)(SO_4)_2:Eu~(2+)的f-f锐线发射强度最大。在Ba_(1-x)Sr_xMg(SO_4)_2:Eu~(2+)中，铕(II)的f-f强度随x增大而变小，d-f发射峰则随x增加而发生红移。运用“电子云扩展效应”和鲍林化学键原理解释了，在Na_(3-x)(PO_4)_(1-x)(SO_4)_x:Eu~(2+)和Na_(2-x)CaSi_(1-x)P_xO_4:Eu~(2+)体系中，随X值在固溶区内变大，铕(II)的发射光谱逐渐移向短波区的现象。为了研究稀七离子的取代格位对其光谱性质的影响，我们合成了K_2Mg_2(SO_4)_3:Eu~(2+)单晶化合物。并经四圆衍射仪解出了结构。铕(II)在单晶中占据Mg_1~(2+)格位，与KMgF_3:Eu~(2+)相比，它将受到更强的晶场作用使4f~65d'能带劈裂幅度变大，又通过计算可知，Eu-O键的共价性比Eu-F键更强，因而在K_2Mg_2(SO_4)_3中Eu~(2+) 4f~65d'重心更低一些。综上所述，K_2Mg_2(SO_4)_3:Eu~(2+)的发射能级(E_(em)~m)要比KMgF_3:Eu~(2+)的发射能级更低。光谱实验数据证实了这一结论。用245 nm激发， K_2Mg_2(SO_4)_3:Eu~(2+)发兰光，最大中心处于400 nm。而KMgF_3:Eu~(2+)发紫色或近紫外光(E_(em)~m = 363 nm)，并且在后者是观察到Eu~(2+)离子的f-f跃迁锐线发射。采用高温氢气还原法制备了SmF_2和SmCl_2作为离子激活源。钐(II)激活的硫酸盐材料的荧光光谱数据表明，在室温条件下该基质中钐(II)的荧光光谱均为4f~55d' → 4f~6跃迁的宽带发射。论文对铕(II)，钐(II)等低价稀土离子的4f~(n-1)5d'激发态性质和稀七离子在基质中的格位取代以及电荷补偿效应也作了较为详细的讨论。

超高灵敏显色反应及其应用的研究

本论文“超高灵敏显色反应及其应用的研究”包括五部分内容：一 文献综述对超高灵敏显色反应、有新机理及其在光度分析中的应用作全面的评述。二 汞（II）－乙基罗丹明B－碘化物体系光度法测定痕量汞仍是常用的方法之一。但是其灵敏度尚待进一步提高，文献中报导测汞最灵敏的罗丹明B光度法ε值为5.44*10~5。本工作研究了汞（II）－乙基罗丹明B－碘化物体系和光度特性。缔合物最大吸收峰位于605nm，表观摩尔吸光系数为1.14*10~6 L.mol~(-1)-cm~(-1)。缔合物可稳定近1小时。汞（II）含量在0.1-2.5μg/25ml时服从比耳定律。试验了17种共存离子的影响，并应用联合掩蔽剂消除干扰。本法可不经分离起直接用于水样分析或经巯基棉分离用于地球化学标样中痕量汞的分析，获得较满意的结果。检测下限为1ppb（湖水，100ml）。三 锑（III）－乙基罗丹明B－碘化物体积以碱性染料萃取光度法测定锑、已有很久历史，但是这类方法存在灵敏度低，操作繁琐，使用有机溶剂等缺点。文献极导最灵敏的水相光度法ε值为3.4*10~5。本工作研究了锑（III）－乙基罗丹明B－碘化物系和光度特性。缔合物λ_(max)=605nm.表观摩尔吸光系数为7.0*10~5 l·mol~(-1)·cm~(-1)。锑浓度在0.1-2.5μg/25ml时服从比耳定律。体系可稳定近1个小时。借助于氢化物发生法分离并富集痕量锑，方法应用于水系沉积物标样中锑的测定，结果与推荐值相符。检测下限为1*10~(-5)％(1g样品)。四 铅（II）－乙基罗丹明B－碘化物体积铅是环保、医药等部门常需检测的有害元素之一。但是，目前光度法测定铅，灵敏度最高者为ε=5.7*10~5，尚待进一步提高。本工作研究了铅（II）－乙基罗丹明B－碘化物体系及光度特性。缔合物λ_(max)=605nm，表观摩尔吸光系数为10*10~6 L·mol~(-1)·cm~(-1)。铅浓度在0.1-3.0μg/25ml时服从比耳定律。缔合物可稳定半小时。试验了22种共存离子的影响，借助于巯基棉分离，本法可用于试剂中铅的测定，结果和对照值一致，检测下限为1*10~(-5)％(1g样品)。五 缔合物形成机理的研究本工作通过吸收光谱研究及缔合物组成比的测定，对显色反应的机理作了初步研讨。吸收光谱研究证明：水溶性大分子PVA_(124)并不参与缔合物组成，它主要是对缔合物起分散和稳定作用；并证实在不同条件下，有两种缔合物形成：R_2(HgI_4)(λ_(max)=587nm)和复杂缔合物(λ_(max)=605nm)。用摩尔比法及等摩尔连续变化法测得组成比为Hg:R=1:14和Sb:R=1:9。这是一种新型的显色反应，推测其反应机理可能是以简单缔合物 [ERB~+]_2·[HgI_4~(-2)]或 [ERB~+]_2·[sbI_5~(-2)]值点为核心，在R~+和I~-浓度较高的条件下，籍范德华力再吸附几个ERB~+I~-缔合物分子形成一种高染料配比的吸附型复杂缔合物，其化学式可能为[（ERB~+）_2·（HgI_4~(-2)]·12[ERB~·I~-]和[（ERB~+）_2·（sbI_5~(-2)]·7[ERB~·I~-]本类超高灵敏显色体系的反应机理十分复杂，影响因素众多，不同作者曾提出过一些看法，但大多缺乏实验根据。本类缔合物的稳定性较差，是深入研究其反应机理的主要困难，尚待继续努力。

对金属稀土金属有机配合物的合成、结构及催化性质研究

合成出三类18种双金属稀土金属有机配合物：第一类：Ln-Li双金属π－烯丙基稀土配合物－LiLn(π-C_3H_5)_4 nD(Ln=La、Tb, n=3; Ln=Y、Dy, n=2.5; Ln=Ce、Pr、Nd、Sm、Gd、Er, n=2; D=二氧六环）。第二类：Ln-Mg双金属π－烯丙基稀土配合物-(π-C_3H_5)_2CnCl_5Mg_2(tmed)_2 (Ln=Ce、Nd)和(π-C_4H_7)_2LnCl_5Mg_2(tmed)_2 (Ln=La、Ce、Nd; C_4H_7=i-C_4H_7)。第三类：Ln-Al双金属配合物－[(CF_3CO_2)_3LnHAlR_2·2THF]_2 (Ln=Y、Nd, R=i-Bu; Ln=Eu, R=Et)。用四园X－ray衍射仪在低温下测定了LiCe(π-C_3H_5)_4·4D、[(CF_3CO_2)_3YHAl(i-Bu)_2 2THF]_2、[(CF_3CO_2)_3NdHAl(i-Bu)_2 2THF]_2和[(CF_3CO_2)_3EuHAlEt_2·2THF]_2的晶体结构。对[(CF_3CO_2)_3YHAl(i-Bu)_2·2THF]_2和LiLn(π-C_3H_5)_4 nD类配合物进行了较详细的NMR研究。二维C－H相关NMR谱表明在[(CF_3CO_2)_3YHAl(i-Bu)_2·2THF]_2配合物中6个CF_3CO_2~-有2个羰基的C与H成键，该结果解释了Ln-Al双金属配合物中相应羰基的非平面结构现象。研究表明LiLn(π-CC_3H_5)_4·nD可催化异戊二烯和苯乙烯均聚合；不同配合物中均以Y配合物的活性为最高。(π-C_3H_5)_2CeCl_5Mg_2(tmed)_2对异戊二烯、丁二烯、苯乙烯以及甲基丙烯酸甲酯（MMA）的聚合有较低的催化活性；(π-C_4H_7)_2LnCl_5Mg_2(tmed)_2也对苯乙烯和异戊二烯的聚合有一定的催化活性。分别以LiCe(π-C_3H_5)_4·4D和(π-C_3H_5)_2CeCl_5Mg_2(tmed)_2作为稀土配位催化剂的模型配合物，研究了其催化所得聚异戊二烯的端基结构。表明聚合物均具有烯丙基端基(-CH_2-CH=CH_2)。证明单体在Ce~(3+)和π－烯丙基之间发生了插入反应，聚合按π－烯丙基机理进行。该结果首次为稀土配位催化共轭双烯烃聚合的活性链端π－烯丙基机理提供了直接的实验证据。(π-C_3H_5)_2CeCl_5Mg_2(tmed)_2-Al(i-Bu)_3(Al/Ce(摩尔比)=4))体系对异戊二烯的聚合具有较高的催化活性，所得聚合物仍具有－CH_3-CH=CH_2端基，而没有i-Bu端基。该结果又一次为上述π-烯丙基机理提供了直接的实验证据。发现Ln(CF_3CO_2)_3-AlEt_3体系可催化THF开环聚合。首次实现稀土催化THF开环聚合。研究了Y(CF_3CO_2)_3-HAl(i-Bu)_2-ECH（环氧氯丙烷）体系催化THF开环聚合法性及聚合机理。讨论了各种聚合条件对该体系催化活性的影响。研究了[(CF_3Co_2)YHAl(i-Bu)_2·2THF]_2在ECH存在下催化THF聚合活性并认为该双金属配合物为Y(CF_3CO_2)_3-HAl(i-Bu)_2-ECH体系的活性体。[(CF_3CO_2)_3YHA(i-Bu)_2·2THF]_2和[(CF_3CO_2)_3EuHAlEt_2·2THF]_2均可催化ECH和MMA聚合，所得PMMA的间同(rr)含量可达76.5％。

东北地区不同小麦品种对黑麦草的化感作用

以东北地区33个不同来源的小麦品种为研究对象,采用琼脂共培法,评价了不同小麦品种对黑麦草所产生的化感作用.通过分析不同小麦品种对黑麦草根长、苗高、根干重及苗干重的影响,探讨不同小麦品种对黑麦草化感作用的差异,从而筛选出具有较强化感潜力的小麦品种.结果表明,不同小麦品种对黑麦草根长、苗高、根干重及苗干重的影响存在显著差异.利用R I���作为化感作用的指标,结合聚类分析方法,可将这33个小麦品种按化感能力的强、中、弱分成3类;其中龙幅麦9号、龙幅麦13号、锦麦2003和小冰麦33号为化感能力较强的品种.

Synthesis and characterization of the titanium complexes bearing two regioisomeric trifluoromethyl-containing enaminoketonato ligands and their behavior in ethylene polymerization

A series of new titanium complexes bearing two regioisomeric trifluoromethyl-containing enaminoketonato ligands (3a-h and 6a-h), [PhN=CRCHC(CF3)O](2)TiCl2 (3a, R = Me; 3b, R = n-C5H11; 3c, R = i-Pr; 3d, R = Cy; 3e, R = t-Bu; 3f, R = CH=CHPh; 3g, R = Et; 3h, R = n-C11H23) and [PhN=C(CF3)CHC(R)O](2)TiCl2 (6a, R = Ph; 6b, R = n-C5H11; 6c, R = i-Pr; 6d, R = Cy; 6e, R = t-Bu; 6f, R = CH=CHPh; 6g, R = CHPh2; 6h, R = CF3) have been synthesized and characterized. X-ray crystal structures analyses suggest that complexes 3c-e and 6c-d all adopt a distorted octahedral geometry around the titanium center. Complexes 3c, 3d and 6c display a cis-configuration of the two chlorine atoms around the titanium center, while complex 6d shows a trans-configuration of the two chlorine atoms. Especially, the configurational isomers (cis and trans) of complex 3e were identified both in solution and in the solid state by NMR and X-ray analyses. With modified methylaluminoxane as a cocatalyst, all the complexes are active towards ethylene polymerization, and produce high molecular weight polymers.

Synthesis, structure and luminescence properties of zinc (II) complexes with terpyridine derivatives as ligands

Five zinc (II) complexes (1-5) with 4 '-phenyl-2,2 ':6 ',2 ''-terpyridine (ptpy) derivatives as ligands have been synthesized and fully characterized. The para-position of phenyl in ptpy is substituted by the group (R), i.e. tert-butyl (t-Bu), hexyloxy (OHex), carbazole-9-yl (Cz), naphthalen-1-yl-phenyl-amine-N-yl (NPA) and diphenyl amine-N-yl (DPA), with different electron-donating ability. With increasing donor ability of the R, the emission color of the complexes in film was modulated from violet (392 nm) to reddish orange (604 nm). The photoexcited luminescence exhibits significant solvatochromism because the emission of the complexes involves the intra-ligand charge transfer (ILCT) excited state. The electrochemical investigations show that the complexes with stronger electro-donating substituent have lower oxidation potential and then higher HOMO level. The electroluminescence (EL) properties of these zinc (II) complexes were studied with the device structure of ITO/PEDOT/Zn (II) complex: PBD:PMMA/BCP/AlQ/ LiF/Al. Complexes 3, 4 and 5 exhibit EL wavelength at 552, 600 and 609 nm with maximum current efficiency of 5.28, 2.83 and 2.00 cd/A, respectively.

Syntheses and crystalline structures of clusters Co-3(CO)(7)(mu(3)-S)(mu, eta(2)-SCNR2)

Through the reaction of Co-2(CO)(8) with four thiuram [R2NC(S)S](2), four new sulfur-capped trinuclear cobalt carbonyl clusters Co-3 (CO)(7) (mu(3)-S) (mu, eta(2)-S* C* NR2) ( I : R = Me; I : R = Et; II : R = i-Pr; IV : NR= -N [GRAPHICS] were prepared and characterized by elementary analysis, IR,H-1 NMR and MS spectroscopy. The crystal structure of the cluster Co-3(CO)(7)(mu(3)-S)[mu, eta(2)-S*C*N (i-Pr)(2)]( III) was determined by X-ray single crystal diffraction method. The crystal of m is monoclinic, belonging to space group P2(1)/n, and the cell parameters are as follows: a = 1, 145 2(2) nm, b = 1. 502 8(3) nm, c = 1, 214 4(2) nmj alpha = 90 degrees, beta = 92, 15(3)degrees, gamma = 90 degrees; V = 2. 088 5(7) nm(3) , Z = 4, F (000) = 1 096, D-c = 1. 747 mg . m(-3), mu = 2. 588 mm(-1), R=0. 040 7, R-w=0. 062 4, The structural analysis shows that cluster II has a pyrimidal Co3S framework and contains a heterocylic bridging bidentate ligand [mu, eta(2)-S* C* N (i-Pr)(2)] linked to the Co2 and Co3 atoms of the cluster by a cobalt-carbon and a cobalt-sulfur bond respectively.

Co_3(CO)_7(μ_3-S)(μ,η~2-SCNR_2)的合成和晶体结构

Co2 (CO) 8 与 4个二硫代双 (烷基硫代甲酰胺 )类前配体 [R2 NC(S) S]2 反应 ,得 4个含烷基硫代甲酰胺基的三核钴羰基硫簇合物 .通过元素分析、IR、 1H NMR和 MS等方法表征了它们的结构 ,用 X射线衍射法测定了其中一个簇合物 Co3 (CO) 7(μ3 - S) [μ,η2 - SCN(i- Pr) 2 ]( )的晶体结构 .晶体属单斜晶系 ,P2 1/n空间群 ,晶胞参数 a=1.1452 (2 ) nm,b=1.50 2 8(3) nm,c=1.2 144 (2 ) nm,α=90°,β =92 .15(3)°,γ =90°,V =2 .0 885(7) nm3 ,Z=4 ,F (0 0 0 ) =10 96 ,Dc=1.74 7mg· m-3 ,GOF(F2 ) =0 .835,μ=2 .588nm-1.最终因子 R[I>2 σ(I) ]=0 . 0 4 0 7,Rw=0 .0 6 2 4

Synthesis of lanthanide-alkylaluminium bimetallic complexes and studies on their catalytic activities for polymerization of some polar monomers

Three new lanthanide (Ln)-alkylaluminium (Al) bimetallic complexes with the formula [(mu-CF3CO2)(2)Ln(mu-CF3CHO2)AIR(2) . 2THF](2) (Ln = Nd, Y, R=i-C4H9 (i-Bu); Ln=Eu, R=C2H5(Et); THF=tetrahydrofuran) were synthesized by the reaction of Ln(CF,CO,), (Ln=Nd, Y) with HAI (i-Bu)(2) and of Eu(CF3CO2)(3) with AlEt(3), respectively. Their crystal structures were determined by X-ray diffraction at 233 K. [(mu-CF3CO2)(2)Nd (mu-CF3CHO2)Al(i-Bu)(2) . 2THF](2) (Nd-Al) and [(mu-CF3CO2)(2)Y(mu-CF3CHO2)Al(i-Bu)(2) . 2THF](2) (Y-Al) are isomorphous and crystallize in space group with a=12.441(3) Angstrom [12.347(5) Angstrom for Y-Al], b=12.832(3) Angstrom [12.832(4) Angstrom], c=11.334(3) Angstrom [11.292(8) Angstrom], alpha=104.93 (2)degrees [104.45(4)degrees], beta=98.47(2)degrees [98.81(4)degrees], gamma=64.60(2)degrees [64.30(3)degrees], R=0.519 [0.113], R(w)=0.0532 [0.110], Z=1 and [(mu-CF3CO2)(2)Eu(CF3CHO2)AlEt(2) . 2THF](2)(Eu-Al) in space group P2(1)/n with a=11.913(6) Angstrom, b=14.051(9) Angstrom, c=17.920(9) Angstrom, alpha=101.88(11)degrees, beta=gamma=90 degrees, R=0.0509, R(w)=0.0471 and Z=2. The six CF3CO2- (including CF3CHO2-) of each complex, among which pairs are equivalent, coordinated to Ln and Al in three patterns: (A) the two oxygen atoms in one of the three CF3CO2- type coordinated to two different Ln; (B) the two oxygen atoms in the second of CF3CO2- type coordinated to Ln and Al, respectively; (C) one of the two oxygen atoms in the third CF3CO2- type bidentately coordinated to two Ln and another oxygen coordinated to Al and one of the two Ln, respectively. Unlike types A and B, in type C the carboxyl carbon with a hydrogen atom bonded to it was found to appear as an sp(3)-hybridized configuration rather than an sp(2)-one. 1D and 2D NMR results further confirmed the existence of such a disproportionated CF3CHO2- ligand. Methyl methacrylate (MMA) and epichlorohydrin (ECH) could be polymerized by Y-Al or Eu-Al as a single-component catalyst and highly syndiotactic poly(MMA) was obtained. THF could also be polymerized by Y-Al in the presence of a small amount of ECH.