Transfer Hydrogenation of C= C Double Bonds Catalyzed by Ruthenium Amido-Complexes: Scopes, Limitation and Enantioselectivity

The reduction of C = C double bonds is one of the most fundamental synthetic transformations and plays a key role in the manufacturing of a wide variety of bulk and fine chemicals. Hydrogenation of olefinic substrates can be achieved readily with molecular hydrogen in many cases, but transfer hydrogenation methods using suitable donor molecules such as formic acid or alcohols are receiving increasing attention as possible synthetic alternatives because it requires no special equipment and avoids the handling of potentially hazardous gaseous hydrogen.     

Synthesis and Crystal Structure of 1,4-Bis(2-hydroxymethylphenyl)-1,4-dioxabutane

1 INTRODUCTION Macrocyclic ligands and their metal complexes have received much attention due to their applications in ion transport, ion separation and as models in biomimic researches[1~7]. The synthetic methods of macrocyclic ligands and their metal complexes are mainly divided into three kinds[8]. The first one is synthesizing free ligand, then forming the metal complexes; the second is template synthesis; and the third is synthesizing the end-off or side-off precursor ligand, then c…     

~1Σ~＋Ni─CO分子簇的从头算研究

采用ＵＨＦ及ＵＭＰ＿２方法，对~１Σ~＋Ｎｉ─ＣＯ分子簇的成键机制进行了从头算研究。计算表明，在σ空间，Ｎｉ~１Ｓ（ｄ~（１０））导出态的主要成键特征是ＣＯ５σ→Ｎｉ４ｓ的授键作用；而Ｎｉ~１Ｄ（ｄ~９ｓ~１）导出态的主要特征是４ｓｐ＿σ极化。在~１Σ~＋Ｎｉ─ＣＯ分子簇中总的成键机制是：ｄ~（１０）导出态中π反馈作用大于σ授键作用；而ｄ~９ｓ~１导出态中σ授键作用强于π反馈作用。由于接受配键机制一定伴随着轨道之间的重叠，因而为了给出合理的Ｍ─Ｌ作用分析，进行补偿计算是重要的。     

镧系离子与L-羟脯氨酸、DL-瓜氨酸配位作用研究

稀土与体内广泛存在的生物配体氨基酸的配位作用，尤其是三元体系的研究对于阐明稀土元素在体内的存在形态及探索稀土生物效应具有重要意义．羟脯氨酸和瓜氨酸均是人体中存在的重要氨基酸，它们在人体血浆中的浓度与必需的氨基酸相近［‘j．稀土与氨基酸配位作用的研究已有较多报道「’‘，但模拟生理条件下稀土离子与羟脯氨酸、瓜氨酸的二元、三元配合物的PH电位法研究尚未见报道．本文报道在模拟生理条件下（37C，0·15mol／LNaCI）湖系离子（Pm和Lu除外）与上述2种氨基酸的二元及三元配合物PH电位法研究结果．1实验部分1．1试剂和仪…     

飞行时间质谱中的空间电荷效应研究

在分子多光子电离实验中, 发现母体离子的飞行时间(TOF)质谱峰随激光强度的提高而展宽, 此现象归因于离子团内离子间库仑排斥作用的空间电荷效应. 为从理论上解释此现象, 尝试了从一个简单的理论模型进行推演, 得到飞行时间质谱峰的半高全宽(FWHM)与激光能量、样品气体的分压比、电极板的总电压、离子质量及所采用的透镜聚焦焦距之间关系的解析表达式, 所得的结果能够很好地说明实验现象.     

Thermodynamic and Equilibrium Composition Analysis of Using Iron Oxide as an Oxygen Carrier in Nonflame Combustion Technology

1. Introduction The utilization of fossil fuels causes serious neg- ative impacts on the environment and human life. There are many pollutants such as SOx, NOx and CO2 emission produced from the combustion of coal, oil and natural gas. It has been known for more than 100 years that CO2 is a greenhouse gas and that the release of CO2 from fossil fuel combustion may affect the climate of the earth. In the last years the concern over the aspects of an increased release of greenhouse gases has…     

三维聚合物双(三丁基锡)戊二酸酯的合成及晶体结构研究

用三丁基氯化锡与戊二羧酸二钠以2:1摩尔比反应,合成了双（三丁基锡）戊二羧酸酯,并用元素分析、红外光谱、核磁共振氢谱及X-射线单晶衍射进行了表征和结构测定。X-射线单晶衍射法测定表明,化合物属单斜晶系,空间群为Cc,晶胞参数:a=13.984（3）,b=16.164（3）,c=16.894（3）A,β=107.457（3）°,V=3642.9（11）A3,Z=4,C29H60O4Sn2,Dc=1.251g/cm3,μ=1.394 mm-1,R=0.0500,wR=0.0874,F（000）=1416。晶体结构中存在2种化学环境不同的三角双锥构型的锡原子,由于配体中2个羧基在不同方向的交联作用,使化合物呈现三维立体骨架结构,并且在骨架结构中存在沿a、b、c轴3个方向伸展的规则的大环直孔道。     

带功能基的全氟烷基乙烯基醚的研究——4.四氟乙烯与全氟-3,6-二氧杂-4-甲基-△~7-辛基磺酰氟溶液共聚反应单体竞聚率的测定

在乙烯-四氟乙烯溶液共聚合体系研究中,我们曾编制了一个简易的计算机程序,用于测定二种单体的共聚竞聚率,这一方法计算方便,而且可以避免原先作图法中的误差,结果较为可靠。前文我们报道了四氟乙烯与两个新的全氟烷基乙烯基醚的共聚合反应,并对其中一个新单体——7,7-二氯-3-氧杂-全氟庚烯-1——与四氟乙烯的共聚进行了单体竞聚率的测定。结果表明,这一新的含氟烯醚单体的聚合活性较其它已有报道的同类单体大。为了验证这一