高取向顺式聚乙炔导电性能的各向异性

用ＥＨＭＯ／ＣＯ方法计算了高取向顺式聚乙炔及其碘掺杂物的二维能带结构，并据此讨论了它们导电性能的各向异性问题，结果表明平行于分子链方向的导电率与垂直于该方向的电导率之比（σ‖／σ⊥）取决于这两个方向上的价带宽和导带宽。碘掺杂后σ‖／σ⊥下降的原因是链间耦合增加。碘掺杂后的顺式聚乙炔是一个链间相互作用微弱的的二维或三维体系。计算结果与实验较好地吻合。     

碘掺杂和非掺杂高取向反式聚乙炔导电性能的各向异性

本文应用量子化学EHMO/CO方法计算了高取向反式聚乙炔及其碘掺杂物的二维能带结构,并以此为依据讨论了它们导电性能的各向异性.平行于分子链方向的电导率与垂直于该方向的电导率之比(σ_■,/σ_⊥)取决于这两个方向上价带宽和导带宽的大小.碘掺杂后σ_■/σ_⊥下降,其原因是链间耦合增强的结果.这也使掺杂后的反式聚乙炔成为链间相互作用微弱的三维体系.计算结果与实验结果较好地吻合.     

磺掺杂和非掺杂高取向反式聚乙炔导电性能的各向异性

本文应用量子化学EHMO/CO方法计算了高取向反式聚乙炔及其碘掺杂物的二维能带结构,并以此为依据讨论了它们导电性能的各向异性.平行于分子链方向的电导率与垂直于该方向的电导率之比(σ~1/σ~⊥)取决于这两个方向上价带宽和导带宽的大小.碘掺杂后σ~1/σ~⊥下降,其原因是链间耦合增强的结果.这也使掺杂后的反式聚乙炔成为链间相互作用微弱的三维体系.计算结果与实验结果较好地吻合.     

磺掺杂和非掺杂高取向反式聚乙炔导电性能的各向异性

本文应用量子化学EHMO/CO方法计算了高取向反式聚乙炔及其碘掺杂物的二维能带结构,并以此为依据讨论了它们导电性能的各向异性.平行于分子链方向的电导率与垂直于该方向的电导率之比(σ~1/σ~⊥)取决于这两个方向上价带宽和导带宽的大小.碘掺杂后σ~1/σ~⊥下降,其原因是链间耦合增强的结果.这也使掺杂后的反式聚乙炔成为链间相互作用微弱的三维体系.计算结果与实验结果较好地吻合.     

溴和碘掺杂高取向反式聚乙炔导电性能各向异性研究

根据固体能带理论,用EHMO/CO方法,计算了高取向反式聚乙炔及溴和碘掺杂态的二维能带结构,讨论了其导电性能的各向异性.研究表明,平行和垂直于分子链方向的电导率之比(σ_///σ_⊥上)取决于这两个方向上能隙和带宽的大小掺杂后σ_///σ_⊥下降是由于掺杂剂使链间栖合作用增强所致.理论计算与实验结果一致.     

硫化反式聚异戊二烯电子性质的理论化学研究

应用量子化学计算方法,对反式聚异戊二烯本征态和硫化态结构的能量及电子性质等进行了计算.结果表明,当聚异戊二烯掺杂硫后,相邻两链之间的距离a⊥变窄,体系的总能量降低,从而使整个掺杂体系更加稳定.另外,在硫化聚异戊二烯分子中,S原子位于两个相邻聚异戊二烯链之间,并偏向于其中一个分子链的C C双键的一侧,即与相邻两链中相对应的两个C C双键形成π-p-π共轭体系,增加了电子在两个聚异戊二烯链间的流动性,从而使硫化的反式聚异戊二烯更加稳定.另外,根据固体能带理论,采用量子化学EHMO方法,对反式聚异戊二烯本征态和硫掺杂态的能带结构进行了计算,根据硫化前后能隙和带宽的变化,解释了反式聚异戊二烯掺杂后呈现电导率各向异性的原因.     

还原态卤代聚苯胺能带结构及掺杂导电机理的研究

用ＥＨＭＯ－ＣＯ方法研究了卤代聚苯胺的能带结构及其掺杂导电机理，结果表明，在掺杂态卤代聚苯胺中形成单极化子晶格；取代主要通过改变带宽影响电导率，由掺杂而大幅度地提高了电导率是因为大大缩小了带隙，并进一步证实了外层ｄ轨道的成键作用。     

部花菁染料的多重电荷转移复合物的研究

自1977年夏在纽约科学院一次会议上Heeger，MacdiarAnd和百）l；英树报告了（CH）。可掺杂到金属态［1］以来，已有许多学者对共轭聚合物的化学掺杂及导电性进行了广泛地研究，用能带模型说明掺杂提高电导的原因．从能带模型可预见只有能隙小，带宽大的共轭聚合物才有可能具有较高的导电性．因为能隙小时离子化电位小，电子亲合力大，易于掺杂．带宽大则掺杂后电子易于迁移问，而与多烯具有相同。电子数的部花育染料的七。x比多烯向更长波长方向位移．例如十六碳八烯的A。。x为410O人而具有同样。电子数的部花育染料BTER的人m。x则为51…     

聚并苯的链间作用对其导电能力的影响

采用量子化学晶体轨道ＣＮＤＯ／ ２ 方法,在考虑聚并苯链间作用的基础上对聚并苯双链模型的电子结构进行计算和讨论．结果表明：聚并苯链处于不同相对位置的链间作用对聚并苯的电荷分布规律及能带结构均有一定影响,位置不同,影响不同．从聚并苯的能带结构可以得出：聚并苯是有较小能隙、良好本征导电性能的半导体材料,考虑链间作用,对能带结构特征未有大的改变,能隙等值略有修正,导电能力有所加强．利用此模型讨论,更接近于晶体的真实结构,对进行聚并苯导电材料的性能改进将有一定帮助．     

由聚苯胺粒子组成的电流变液的研究

由经碱处理的掺杂态聚苯胺（ＰＡｎ）制得高介电常数的半导体ＰＡｎ粒子，将其悬浮于电绝缘油可组成电流变液，讨论了电流变（ＥＲ）液的静态屈服应力（τ＿ｓ），电流密度等性能与ＰＡｎ的介电常数（ε＿ｐ），导电率（σ），体积分数和应用电场强度的关系。对导电率相同的ＰＡｎ粒子，用氨水处理的ＰＡｎ粒子ε＿ｐ较用ＮａＯＨ液处理的高，前者在σ足够低如σ≤１．０×１０￣（－７）／ｃｍ时，ＥＲ液的τ＿ｓ随偶极系数的平方（β￣２）的增大而呈现非线性增加；后者ＥＲ液的τ＿ｓ随β￣２的增大出现一最大值．结果表明：由聚苯胺粒子可组成高电流变活性的无水ＥＲ液．     

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%.     

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.     

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.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.