Mo~2S~4[S~2CNC~4H~8]~2的合成、结构表征及其与Cu^+,Ni^2+的反应

由(NH~4)~2Mo~2S~12H~2O和(NH~4)(S~2CNC~4H~8)在PPh~3参与反应下,获得Mo~2S~4(S~2CNC~4H~8)~2化合物,对此二核钼簇合物进行了红外、电子光谱、电化学及单晶X射线结构表征,并尝试与多种金属化合物进行[2+1]反应,从反应产物的晶体结构分析发现了包括金属夺取端基S^2-形成Mo~2O~2S~2(S~2CNC~4H~8)~2化合物,Cu^+被氧化并夺取配体(S~2CNC~4H~8)^-形成Cu(S~2CNC~4H~8)~2以及Mo(V)还原为Mo(IV),S^2-氧化为(S~2)^2-而形成Mo~3(μ~3-S)(μ-S~2)~3[S~2CNC~4H~8]~3.     

电化学及光谱电化学方法研究辅酶B~12 模型化合物的生成与解离.I.

本文用电化学及光谱电化学方法研究了钴卟啉与苄基氯的相互作用,表明形成有σ钴-碳键的辅梅B~12模型化合物的前提条件是钴卟啉的中心钴氧化态必须降低到I价.讨论了σ钴-碳键的形成和解离与电位的关系,现场检测到辅酶B~12模型化合物的形成和解离的紫外可见光谱,提出了钴 中啉与苄基氯的ECF作用机理.     

过渡金属催化的炔烃复分解反应

综述了过渡金属均相催化的炔烃复分解反应进展,主要分为两部分：一是炔烃复分解反应在炔烃合成中的应用,即从六、七十年代Mortreux催化剂的发现能均相催化炔烃的歧化反应,经过一系列的条件改造,合成了炔醚和二芳基乙炔等化合物,并提出了可能的两种机理：金属卡宾和金属卡拜机理;金属钼和钨的卡拜络合物相继合成,发现此类络合物能够催化官能化的二炔的复分解反应,合成一系列的大环化合物。二是炔烃复分解反应在合成高聚物中的应用,即钙和钨的卡拜络合物被用来催化ROMP和ADIMET反应合成高聚物,改良了的Mortreux催化剂也能催化高聚物的生成,这些高聚物在发光器件、有机"塑料"激光、液晶显示器上都有应用。     

疏水-亲脂相互作用对反应性的影响5.长链硫醇和长链羧酸酯酯交换反应的接近效应

本工作研究了不同链长羧酸的对硝基及其它取代苯与不同链长硫醇间的酯交换反应动力学,所用溶剂为Me2SO-H2O,CH3COCH2-H2O及C2H5OH-H2O混合体系,在Me2SO-H2O中,长链硫醇和长链酯之间的反应速度比相应的短链硫醇与短链酯,长链硫醇与短链酯及短链硫醇和长链酯之间的反应速度快得多,这是由于疏水-亲脂相互作用使两个反应物分子互相接近而引起的加速效应,这种接近效应依赖于溶剂组成。在Me2SO-H2O中,接近效应随Me2SO含量增加而迅速减小;在良溶剂体系中,不存在接近效应,在Φ=0.45Me2SO中,十二硫醇相对于丁硫醇的加速效应约为160倍。     

含手性侧链结构的1, 5-二氮环辛烷的合成

手性α-氨基醇和原氯乙酸三乙酯作用,可同时分离得到两种手性侧链：酰胺醇(2a,2b)和恶唑啉(2c,2d);分别和1,5-二氮环辛烷反应,生成带手性侧臂的1,5-二氮环辛烷化合物(1a～1d),其结构经红外、核磁、质谱和元素分析等得到了证实。     

二氮双环阳离子游离基中N,N'-三电子键

用从头算HF/3-21+G^*优化了二氮双环[m,n,l]游离基阳离子(m,n,l≥2～5)。分子[4,4,4]和[2,2,2]^+.,[3,3,3]^+.,[4,4,4]^+.游离基阳离子的优势构型有D3对称性,而其它游离基阳离子的优势构型为非对称性。通过比较这些阳离子几何构型,HOMO和NHOMO(即NextHOMO和HOMO-1),和由MNDO计算确定的原子对作用能,表明当二氮双环游离基阳离子的桥链(CH2)n的n≥3时,桥头氮原子通过空间相互用用形成了一个弱的N,N'-三电子σ键。形成的三电子键强度不随环的扩大而增强。而三电子键强度被两个因素影响：一个是桥头氮原子间的p轨道重叠的取向;另一个是它们相应p轨道成分。     

Effect of postgrafted alkyl chains on the wettability of hydrophilic poly(amidoamine)-grafted nano-sized silica

In order to control the surface wettability of hyperbranched hydrophilic poly(amidoamine) (PAMAM)-grafted nano-sized silica, hydrophilic alkyl chain (C _n H_2n+1) with different chain lengths (n = 4, 8, 15) were postgrafted onto PAMAM-grafted silica by the reaction of terminal amino groups of PAMAM grafted on the silica surface with alkyl acid chlorides (C _n H_2n+1-COCl). The postgrafting of C _n H_2n+1-COCl increased with increasing PAMAM grafting and alkyl chain length of C _n H_2n+1-COCl. However, the terminal amino groups of PAMAM-grafted silica used for the postgrafting of C _n H_2n+1-COCl decreased with increasing chain length. This may be due to the steric hindrance between terminal amino groups of PAMAM-grafted silica and C _n H_2n+1-COCl: the steric hindrance is considered to increase with increasing chain length of C _n H_2n+1-COCl. The surface wettability was estimated by contact angle measurement for water and methanol wettability. As a result, it was found that contact angle and methanol wettability increased with increasing alkyl chain length of postgrafted C _n H_2n+1-COCl. The hyperbranched PAMAM-grafted silica readily dispersed in water and methanol because of the hydrophilic nature of grafted PAMAM, but it lost dispersibility in water and methanol due to postgrafting of hydrophobic chains.     

Interfacial strengthening of high-impact polypropylene compounds by reactive modification

The effects of reactive modification on the interfacial strength in high-impact polypropylene materials have been investigated using a model system and demonstrated in two specific examples on high flow materials for thin wall injection moulding and reinforced compounds for engineering applications. Using Borealis' proprietary modification technology, the modification degree was controlled by varying the free radical initiator and co-agent content, respectively. The influence of the modification degree on the formation of ethylene-propylene copolymer grafted to polypropylene, which is believed to be the main reason for the strengthened interface between the PP matrix and EPR particles, the phase morphology and material properties was investigated. Depending on practical application requirements, a well defined material performance such as toughness, flowability, surface stability, etc. could be adjusted.     

RAMAN SPECTROSCOPIC STUDY ON THE CHAIN CONFORMATION OF ELECTROSYNTHESIZED POLY(p-PHENYLENE) FILMS

Poly(p-phenylene) (PPP) films have been electrochemically deposited on mirrorlike stainless steel (SS) electrode surfaces by direct oxidation of benzene in boron trifluoride diethyl etherate (BFEE) solutions at a constant applied potential of 1.7 V (versus Ag/AgCl). The chain conformations of as-grown PPP films have been studied by Raman spectroscopy. The results demonstrated that high synthesis temperature favors the formation of planar PPP, and the conformation of planar PPP can be changed into torsional PPP by cooling treatment.     

Toda Chains with Type Am Lie Algebra for Multidimensional m-component Perfect Fluid Cosmology

We consider a D-dimensional cosmological modeldescribing an evolution of Ricci-flat factor spaces,M₁,..., M_n (n 3), in thepresence of an m-component perfect fluid source (n– 1 m 2). We find characteristicvectors, related to the matter constants in thebarotropic equations of state for fluid components ofall factor spaces. We show that, in the case where wecan interpret these vectors as the root vectorsof a Lie algebra of Cartan type A _m = sl(m + 1, i), the model reduces tothe classical open m-body Toda chain. Using an eleganttechnique by Anderson for solving this system, weintegrate the Einstein equationsfor the model and present the metric in aKasner-like form.