运用微机求等价电子j-j偶合的J值

推求等价电子组态 j-j 偶合谱项的难点在于推求组合组态(j)_J~x 的 J 值。我们使用 PASCAL 语言编制了计算程序,在 Apple-Ⅱ、IBM-PC/XT 微机上调试、运行。整个程序由三个子程序完成。为准确求出组合组态(j)_J~x 的 J 值,使用了递归调用技术,使求取 J 值的繁杂工作变得异常简便。该程序的特点是快     

价电子组态参数Ve与镧系元素理化性质的相关性研究

由元素的价电子组态构建的三个矩阵A、B、C及原子序数Z定义了价电子组态参数：Ve=ZABC与镧系元素的12种物理化学性质（P）按数学模型P^m=bVe^d a(m,d,b,a为常数）进行关联。结果表明，Ve不仅与镧系元素的12种理化性质呈现更令人满意的相关性及对所有元素达到唯一性表征，而且在表达各元素的结构特征上较其他文献更清晰、方法更简单。     

MRCISD程序的改进

报道了一个改进的多参考态组态相互作用计算程序,通过对照计算比较了该程序与Gaussian-94W和Gaussian-98W中CISD的效率,并在微机上实现了组态数超过10^7的大规模CI计算。此外,为了使CI计算能够应用于更大的体系,还报道了一些近似CI方法的计算结果。     

气相色谱仪自动进样器开发平台的软件研制

基于平台化、模块化的设计理念,并行研制开发出两种不同结构的液体自动进样器.软件设计采用分层与模块化的方法,通过程序功能模块的复用与重组,在同一个研发平台上成功实现了两种自动进样器的工作流程.设计解决了直流有刷电机与两相步进电机的兼容问题和四轴电机的驱动问题,为进样器产品的快速研发提供了一种新的思路与方法.     

空穴-粒子对称的图形酉群方法在多参考态组态相互作用中的应用

空穴-粒子对称的图形酉群方法(graphic unitary group approach,GUGA)被用于发展高效的多参考态组态相互作用(multi-reference configuration interaction,MRCI)程序.通过将轨道空间划分为双占据轨道、活性轨道和外轨道空间分别处理,耦合系数可以写为三个空间片段因子的乘积.由于仅需搜索和保存活性空间的片段因子,其余两个空间的片段因子可以根据图形类型直接确定,从而避免了部分耦合系数随内空间增大无法保存的难题,使MRCI可被用于超过32个内轨道的计算.空穴一粒子对称允许我们将MRCI的组态空间按照双占据空间空穴数和外空间电子数自然划分为子组态空间,内收缩函数可以分别定义在子组态空间中.在此基础上,我们提出了基于GUGA的内收缩MRCI新方案并程序化.测试表明,未收缩组态空间超过10亿的MRCI已成为可以在普通工作站上完成的常规计算.     

组态相互作用计算中耦合系数的快速确定

提出了组态相互作用 (CI)计算中确定耦合系数和分子积分新的算法 .这些算法明显地提高了CI计算程序的效率 .比较了改进的CI程序与MELD和Gaus sian 94程序包中CI计算的效率 .     

基于完全活性空间自洽场的杂化多组态密度泛函方法λ-DFCAS（英文）

提出了一种杂化多组态密度泛函新方法——λ-DFCAS.在λ-DFCAS方法中,电子相关能被分为静态和动态相关能.静态相关能由多组态波函数方法完全活性空间自洽场(CASSCF)得到,而动态相关能由密度泛函理论方法描述.两种相关能的杂化比例由一个可调节的参数λ控制.参数λ的取值取决于分子体系的多组态特性,在0～1之间变化,从而使得λ-DFCAS可以应用于各种强相关分子体系.该方法能够以与CASSCF相当的计算代价获得接近完全活性空间二阶微扰(CASPT2)的计算精度,并具备了大小一致性.     

基于完全活性空间自洽场的杂化多组态密度泛函方法λ-DFCAS

提出了一种杂化多组态密度泛函新方法——λ-DFCAS. 在λ-DFCAS方法中, 电子相关能被分为静态和动态相关能. 静态相关能由多组态波函数方法完全活性空间自洽场(CASSCF)得到, 而动态相关能由密度泛函理论方法描述. 两种相关能的杂化比例由一个可调节的参数λ控制. 参数λ的取值取决于分子体系的多组态特性, 在0~1之间变化, 从而使得λ-DFCAS可以应用于各种强相关分子体系. 该方法能够以与CASSCF相当的计算代价获得接近完全活性空间二阶微扰(CASPT2)的计算精度, 并具备了大小一致性.     

组态相互作用中的特征波函数

提出了完全活性空间组态相互作用方法中对称化算符、本征基、特征矩阵、特征波函数等概念和将多电子波函救按空间与自旋对称分类的统一方法。按此法对称化算符并作用在特征波函数上,再按等价权空间求和即得全组态波函数。因对称性使组态函数中物理因子与几何因子完全分离,可消除了变分求解中多余的变量。特征基化学概念明确,直接对应给定的价键结构。     

双收缩CI方法及其应用

提出了一种近似的基于空穴-粒子对称的双收缩CI方法. 该方法一般能使组态数减少3个数量级, 计算时间减少一个数量级. 通过一系列比较计算, 表明该方法能够重现非收缩CI计算结果, 并达到了理想的计算精度.     

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.     

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.     

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.     

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.     

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.