Structure-Activity Relationship of Insecticidal Steroids. V. 3β-Benzoyloxystigmastan-6-ones

The toxicity of steroid benzoates 4-10 for Colorado beetle (Leptinotarsa decemlineata Say.) larvae was studied by a contact-intestinal method. The most active growth and development regulator for this insect is 3-benzoyloxy-5-hydroxy-⁷-6-ketosteroid 9a.     

Kraftfeldrechnungen an linearen Oligopyrrolen: 2,2′-Bipyrrol, 2,2′-Furylpyrrol und Prodigiosen

Using a specific force field model, relative stabilities of 2,2-bipyrrole and 2,2-furylpyrrole conformers as well as of prodigiosene tautomers, configurations, and conformations, are studied. 2,2-Bipyrrole adopts anantiperiplanar conformation in accord with other theoretical calculations and experimental findings. Its rotational barrier calculated by this method compares favourably to the one derived by other means. For the parent prodigiosene the (Z)sp,sp arrangement is found to be the most stable one. The two possible tautomers within its dipyrrin fragment do not show a significant energy difference.

     

Zustandsbarogramme — Zustandsdiagramme durch Gesamtdruckmessungen

From phasebarograms it is possible to construct phase diagrams. We show on example of the system Bi/Se/O how follow ternary sections from the total pressure measurements in equilibrium and how we can attribute the barogram of the ternary region Bi₂Se₃/Bi₂O₂Se/Se to the binary system Bi₂Se₃/Se. The knowledge of the ternary system Bi/Se/I and its coexistent pressure courses allow to followT-p-x conditions for the chemical transport of phases from this system.

     

红外光谱研究甲烷和氧与SrO-La2O3/CaO表面的相互作用

在甲烷氧化偶联（ＯＣＭ）反应条件下，用原位红外光谱研究ＳｒＯ－Ｌａ２Ｏ３／ＣａＯ催化剂，结果表明，晶格氧使甲深度氧化，Ｌａ２Ｏ３和ＣａＯ具有活泼的晶格氧，ＳｒＯ的晶格氧比较稳定，气相氧通过催化剂表面消耗掉的晶格氧，加速甲烷了深度氧化，另一方面，催化剂表面的碳酸根物种在氧气氛下分解，在Ｌａ２Ｏ３和ＬＣ催化剂中，催化剂表面Ｌａ２Ｏ２（ＣＯ３）的分解形成配位不饱和的晶格氧Ｏ＾２－，并为气相氧吸附提供氧空     

核／壳结构增韧剂对环氧树脂的抗冲改性

核／壳结构增韧剂对环氧树脂的抗冲改性张明耀，张会轩，杨海东，冯之榴（吉林工学院化学工程系长春１３００１２）（中国科学院长春应用化学研究所长春）关键词核／壳结构，增韧剂，环氧树脂，共混核／壳结构增韧剂是用分步乳液聚合技术制造的一种复合乳胶粒子，其核为橡...     

5,7,8位取代的喹诺酮类化合物定量构效关系的量子化学研究

５，７，８位取代的喹诺酮类化合物定量构效关系的量子化学研究俞庆森，朱龙观，林瑞森，蔡国强（浙江大学化学系杭州３１００２７）关键词：氟喹喏酮类，定量构效关系，ＣＮＤＯ／２氟喹诺酮类是一类重要的抗感染化疗药物￣［１］，近十年对其研究进展神速￣［２］，结构...     

双核铁原子簇体系的CI计算

用ＩＮＤＯ／ＣＩ方法研究了含有Ｆｅ－Ｆｅ键的原子簇体系［Ｆｅ２Ｓ２Ｘ４］＾２－（Ｘ＝Ｃｌ，Ｂｒ，Ｉ）的电子光谱及电子结构，对于这些多谱带体系，谱带波数计算值与实验值符合，在谱带的指认分析中，发现了πｄ＾１→πｄ等新的跃迁方式，对跃迁方式作了解释和分类，并讨论了谱带的电荷转移性质，此外，还对体系的化学键等性质进行了分析。     

Synthesis and characterisation of bis(pentafluorophenyl)antimony(V) cations, [(C6F5)2SbL3]

Pentacoordinate complex cations of the general formula [(C₆F₅)₂SbL₃]³⁺ stabilized as solid salts in combination with tetraphenylborate (BPh₄), tetrafluorobroate (BF₄) anions, where L=DMSO, Ph₃AsO, PyO, DMF, α-, β- and γ-picoline have been isolated. The newly formed complexes were characterized by elemental analysis, molar conductance measurements, solid-state IR and and NMR. From these results, a five-fold coordination around antimony was required.     

Chemical reactivity of [1,2,3]triazolo[1,5-a]- and [1,5-c]-pyrimidinium salts

The chemical reactivity of the [1,2,3]triazolo[1,5-a]- and [1,5-c]-pyrimidinium salts towards morpholine, water and sodium methoxide have been studied. Among others, new 1-aza and 2-azabutadienes substituted by a [1,2,3]-triazole ring were obtained in the course of the opening of the positively charged pyrimidine ring.     

Complete-active-space self-consistent-field/Amber parameterization of the Lys296–retinal–Glu113 rhodopsin chromophore-counterion system

A special hybrid quantum mechanics/molecular mechanics forcefield is defined, parameterized and validated for studying the photoisomerization path of the retinal chromophore in the rhodopsin protein. It couples a multireference ab initio Hamiltonian (CASSCF and second-order multireference many-body perturbation theory using a CASSCF reference) to describe the chromophore while the rest of the protein is approximated with the Amber forcefield. The frontier has been carefully parameterized in order to reproduce full quantum mechanics torsional energy profiles, for both the ground state and the first excited state. It is also shown that replacing the chromophore counterion with point charges is a valid approximation. This result is interpreted in terms of a cancellation effect for which a possible explanation is given.