聚硅烷链形状的Monte Carlo研究

用ＭｏｎｔｅＣａｒｌｏ方法对θ溶液中考虑二级相互作用的聚硅烷链的形状进行了研究。结果表明聚硅烷链的形状明显偏离球形，它与链长有关，长链极限的比值＜Ｌ２１＞∶＜Ｌ２２＞∶＜Ｌ２３＞约为１∶２．７∶１２．１。还发现聚硅烷链转动惯量的最长主轴与末端距矢量之间夹角的统计平均值＜θ＞的极限值约为２７°。     

受限于平行界面之间高分子链力学行为的研究

采用PERM(pruned-enriched-rosenbluth method)算法,和简立方格点上的自避行走模型,研究了受限于平行界面之间的星型高分子链和线型高分子链的力学行为,并将两种结果进行了比较.模拟结果表明,如果界面对高分子链存在吸附作用,界面之间距离D的增大需要外力的作用;如果界面对链没有吸附作用,则D的增大是一个自发的过程,无需外力的作用.随着界面间距D的增大,通过计算星型链和线型链的均方回转半径〈S2〉和形状因子〈δ*〉,研究了链尺寸和形状的变化情况.另外,为了更细微地了解星型链和线型链的结构及力学行为,还研究了受限高分子链在平行界面之间的轨链(train)、环链(bridge)和尾链(tail).     

铕对决明发根生长及有效成分生成的作用

以决明发根为材料,在培养基中附加０．００１～１０ｍｇ．Ｌ＾－１Ｅｕ＾３＋（ＥｕＣ１３）,测量发根的鲜重和干重,用高效液相色谱法测定游离蒽醌化合物含量。发有低剂量（０．００１,０．０１,１．０ｍｇ．Ｌ＾－１）Ｅｕ＾３＋抑制生长,０．００１ｍｇ．Ｌ＾－１Ｅｕ＾３＋抑制作用最强,干重比对照降低２２％;较低剂量（１０ｍｇ．Ｌ＾－１）Ｅｕ＾３＋处理的含量高于对照２６＾,高于Ｅｕ＾３＋１．０ｍｇ．Ｌ＾－１处理     

线形、梳形和星形高分子静态和动态性质的模拟

以梳形高分子为纽带,基于粗粒化分子动力学模拟方法,研究了线形、梳形和星形拓扑结构高分子的静态和动态性质,以揭示稀溶液中高分子链行为与链拓扑结构依赖关系的一般性规律.研究结果表明,随着线形-梳形-星形的链拓扑结构转变,回转半径的标度关系由仅依赖分子聚合度转变为同时依赖链聚合度与臂数或侧链数.分析了星形高分子和梳形高分子的静态和动态性质的特征规律.星形高分子的臂数增加使其尺寸迅速减小,形状则由长椭球形转变为类球形,且扩散系数也随之增加;其均方回转半径(〈R_g〉)和扩散系数(D)与分子聚合度(N)及臂数(f)的标度规律为〈R_g〉~N~(0.581)f~(-0.402),D~N~(-0.763)f~(0.227).梳形高分子的静态与动态性质与分子聚合度及侧链数的依赖关系为〈R_g〉~N~(0.597)f~(-0.212)(每个支化点只有一条侧链)和〈R_g〉~N~(0.599)f~(-0.316)(每个支化点有多条侧链).     

酸性镀铜体系的交流阻抗研究

研究了基础溶液（０．３ｍｏｌ／ＬＣｕＳＯ４＋１．９４ｍｏｌ／ＬＨ２ＳＯ４）以及添加６０ｍｇ／ＬＣｌ＾－，３００ｍｇ／ＬＯＰ－２１，３０ｍｇ／ＬＰＥＧ－６０００，１０ｍｇ／Ｌ２－噻唑啉基－二硫丙烷酸钠（代号ＴＤＹ，自合成添加剂）后体系的阻抗行为，结果表明：１）Ｃｌ＾－在铜沉积中有增大阴极极化的作用；２）铜离子的放电为分步反应；即Ｃｕ＾２＋→Ｃｕ＾＋；Ｃｕ＾＋→Ｃｕ（吸附）→Ｃｕ（晶格），在含有Ｃｌ＾     

金刚石格点上自回避行走高分子链的构象熵

计算了链长Ｎ为１０－１９的金刚石格点上自加避行走高分子链的构象熵Ｓ和平均ｇ态个数〈Ｗｇ〉。发现Ｓ和〈Ｗｇ〉均与Ｎ成线性关系，每键构象β和ｇ态密度μ都随参数к（к＝кＢＴ／ε）的变化而变化，参数к是温度，键构象能ε有关的量。β随参数к的变化可划分三个区域，（１）│к│≥２．０，β的值几乎与к的大小无关，几乎接近于β的极值；（２）０．１６〈│к│〈２．０，β的变化非常明显；（３）│к│≤０．１６，β的     

铜钨杂多酸—耐尔蓝离子缔合显色反应及其应用

在阿拉伯胶存在下铜钨多酸与耐尔蓝形成离子缔子缔合物，其最大吸收位于５８０ｎｍ；表观摩尔吸光度ε值为２．２２＊１０＾６Ｌ．ｃｍ ＾－１；铜量在０－２４μｇ／Ｌ范围内服从比耳定律；检测限（３σ）１．０μｇ／Ｌ（ｎ＝１０）；分析１６μｇ／Ｌ铜的ＲＳＤ＝１．５％（ｎ＝１１）；离子缔合物的摩尔比为Ｃｕ：Ｗ：ＮＢ＝１：１２：４。     

多检测GPC／SEC技术在高分子表征中的应用：Ⅲ.新型聚炔类梳形？…

采用体积排斥色谱法／示差折光指数／直角激光光散射／示差粘度三检测联用技术表征聚炔类梳形液晶高分子,阐述了在溶液中分子尺寸与结构的关系,计算了无无扰尺寸（〈ｒ０＾２〉／Ｍ）＾１／２和Ｆｌｏｒｙ特征比Ｃ∞,讨论了侧基的柔性和体积对主链柔性程度的影响。     

2—（5—溴—2—吡啶偶氮）—5—二乙氨基酚与铅（Ⅱ）,锌（Ⅱ）络合平衡的双…

本用双系列线性回归法研究了Ｐｂ（Ⅱ），Ｚｎ（Ⅱ）与５－Ｂｒ－ＰＡＤＡＰ的络合反应，发现在ｐＨ５－６．５，３０％乙醇溶液中，Ｐｂ（Ⅱ）与５－Ｂｒ－ＰＡＤＡＰ形成１：１络合物，Ｚｎ（Ⅱ）主要形成１：２络合物。两种络合物的稳定常数（１ｇβ）分别为１１．１７，２２．３１，最大吸收波长分别为５７５，５５０ｎｍ，摩尔吸光系数分别为６．０１×１０＾４，１．３４×１０＾５Ｌ．ｍｏｌ＾－＾１．ｃｍ＾－＾１。     

一价铜配合物[Cu（C8H4F3O2S）（PPh3）2]的事成和晶体结构

室温下，铜粉和２－噻吩甲酰酰三氟丙酮，三苯基膦在甲醇和四氢呋喃混合溶剂中反应，生成一价铜的配合物［Ｃｕ（Ｃ８Ｈ４Ｆ３Ｏ２Ｓ）（ＰＰｈ３）２］，测定了该配合物的晶体结构，结果表明，晶体属单斜晶系，Ｐ２１／ｎ空间群晶胞参数：ａ＝１０．５８４（ａ），ｂ＝１６．７３８（１），ｃ＝２２．７２８（９）Ａ；β＝９４．２２（２）°，Ｖ＝４０１５．２ａ＾３，Ｍｒ＝７８５．２９，Ｚ＝４，Ｄｃ＝１．２９９ｇ／ｃｍ＾３，     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.