Laser-induced reactions of NO2 in the visible region

The reaction of NO₂ with isobutane, induced by 488 nm laser radiation, to form 2-nitro-2-methylpropane has been investigated and the results computer-modeled according to two possible reaction mechanisms. The first scheme involves the direct abstraction of H from isobutane by vibronically excited NO₂ (NO ₂ ^* ), and the second, abstraction by an intermediate NO₃ radial produced by NO ₂ ^* +NO₂. The modeling results strongly support the NO ₂ ^* scheme as the dominant reaction mechanism.     

含dppm桥的双核过渡金属配合物中金属─金属间的相互作用

应用ＥＨＭＯ法研究了一系列含ｄｐｐｍ双二苯基膦甲烷桥的双核过渡金属配合物［ＰｄＢｒ（ｄｐｐｍ）］_２，Ｍ_２Ｃｌ_２（μ－ＣＯ）（ｄｐｐｍ）_２（Ｍ＝Ｐｄ，Ｒｈ），［ＲｈＣｌ（ＣＯ）（ｄｐｐｍ）］_２，Ｍ_２－（μ－Ｃｌ）_２Ｃｌ_４（ｄｐｐｍ）_２（Ｍ＝Ｎｂ、Ｔａ、Ｒｅ、Ｒｕ）的电子结构。根据配合物的成键特征，对其金属－金属的相互作用进行了分析。计算结果可以作为解释这类配合物的某些物理化学性质的理论依据。     

自增强高性能聚合物的成型工艺同力学性能间相关性研究——1.超高分子量聚乙烯的应力诱导结晶理论和其自增强作用

本文发展了一种高分子量聚合物熔融体的应力诱导结晶结构形态模型,它是由微晶聚集体(以下简称微区)-高分子链组网和缠结网的网络结构组成。基于上述模型,把二种网中的单个链组作为独立的统计单元和形变单元,计算了二种网中单个链组的末端距分布函数,进一步计算了二种网和总网的形变自由能。在此基础上,讨论了诱导结晶结晶机理和自增强聚合物网络自由能的依赖性,并着重地研究了超拉伸高聚物的起始熔点拉伸比间的关系。用超高分子量聚乙烯膜和超取向高密度聚乙烯纤维的起始熔点和拉伸比的实验数据进行处理,得到理论予期的近似直线关系,初步验证了聚合物网应力诱导结晶理论。     

κ-卡拉胶热可逆凝胶化行为研究

用固体小角激光散射方法研究κ 卡拉胶 (KC)的热可逆凝胶化行为 .以散色斑点的突停点温度为体系的凝胶化点Tgel,考察了溶液中加入Na+ ,K+ ,NH+4,Ca2 + ,Cu2 + ,Zn2 + 等抗衡离子对Tgel的影响 .结果是随抗衡离子浓度增大Tgel上升 ;Tgel与Na+ 的浓度呈线性关系 ,与K+ ,NH+4,Ca2 + ,Cu2 + ,Zn2 + 等离子浓度的平方根成线性关系 ;另外 ,还得到 30℃时KC在KCl盐溶液中的溶胶 凝胶相图 ,并对比了KC在NaCl溶液中透析前后Tgel的变化 .     

对硝基氯苄与活性亚甲基化合物的反应

对硝基苄基衍生物可以与许多阴离子起单电子转移的亲核取代反应。Kornblum等以对硝基氯苄为底物,2-乙氧羰基香豆满-3-酮的钠盐为阴离子,作了深入的研究,得出对硝基氯苄与2-乙氧羰基香豆满-3-酮钠盐的C-烷化反应机理为自由基链式亲核取代反应。同时,Russell等提出对硝基氯苄与2-     

An open chain product in the reaction of benzil with thiocarbohydrazide

An open chain compound was obtained by reaction of benzil with thiocarbohy-drazide in acidic condition. Its derivative, namely, benzil bis-(5-isopropylidene-3-thiocarbohydrazone) has been structurally characterized by X-ray single crystal diffraction method. Crystallographic data: C22H26N8S2, Mr=466.62, monoclinic, space group C2/c, a=12.215(3), b=11.473(2), c=17.032 (3)A, B=98.96(2)0, V=2357.7(9)A3, Z=4, Dc=1.32 g/cm3, F(000)=1040, u(Mo Ka)=2.43 cm-1. Final R=0.050, Rw=0.061 for 1103 unique and observed reflections with I> 3o(I). The effect of the structures on the formation of the open-chain intermediates during the cyclization of (2:2) Schiff base macrocyclic compound has been discussed and a possible mechanism for the ring closure has been suggested.     

Oxidation of dibenzothiophene catalyzed by heme-containing enzymes encapsulated in sol-gel glass

We have encapsulated several hemoproteins in the sol-gel glass to catalyze the oxidation reaction of dibenzothiophene (model for organic sulfur compounds in coal) with hydrogen peroxide. In addition to cytochrome c and myoglobin, which have previously been encapsulated in sol-gel glasses, two other hemoproteins, horseradish peroxidase and bovine blood hemoglobin, have now been successfully immobilized in sol-gel media with the retention of their spectroscopic properties. All four hemoproteins studied also demonstrate similar catalytic activities toward the oxidation of dibenzothiophene as compared with the results obtained with the proteins in solution. In the case of encapsulated cytochrome c, the more water-soluble S-oxide was obtained with much higher selectivity over the less water-soluble sulfone (S-oxide/sulfone = 7.1) as compared to what was obtained in the aqueous/organic medium (S-oxide/sulfone = 2.3). Because of the advantage of easy separation of the encapsulated proteins from the liquid reaction mixture, it is clear from these studies that the immobilization of active hemoproteins in the solid glass media could serve as more practical biocatalysts.     

四（α—噻吩甲酰三氟丙酮）合铕（Ⅲ）酸十六烷基吡啶LB膜的研究

标题配合物（Ⅰ）和硬脂酸（Ⅱ）的CHCl3溶液按不同摩尔比Ⅰ：Ⅱ=1：α（α=1,2,4,8,12)混合后，α≥2时，其π-A曲线比单一的标题配合物的有明显改善，Ⅰ：Ⅱ=1：4时，在亲水石英基片上制备了Z型LB膜，并用紫外光谱、荧光光谱和小角X射线衍射进行了表征。