两种不同晶形的邻羟基苯甲酸钬配合物的合成与晶体结构

合成了两种不同晶形的配合物，其组成分别为［Ｈｏ_２（ｏ－ＨＯＣ_６Ｈ_１ＣＯ_２）_６（Ｈ_２Ｏ）_４］·４Ｈ_２Ｏ及［Ｈｏ（ｏ－ＨＯＣ_６Ｈ４ＣＯ_２）_３·（Ｈ_２Ｏ）_２·２Ｈ_２Ｏ］_ｎ，用Ｘ射线衍射法测定了它们的结构：一种以二聚体形式存在，属三斜晶系（Ⅰ），其中钬离子的配位数为９；另一种呈无限链状聚合结构，属单斜晶系（Ⅱ），钬离子的配位数为８．同时还研究了它们的热分解过程．     

不同SnO2晶体结构的力学性能及电子结构

采用基于密度泛函理论(DFT)的平面波超软赝势法, 用广义梯度近似(GGA)PBE交换相关泛函, 对高压相变产生五种不同SnO2晶体结构的电子结构和力学性质进行了第一性原理计算. 计算结果表明, Pnam型SnO2的形成相对困难, 体模量较大, Pbca和Pnam型SnO2的维氏硬度值相差不明显. 不同晶体结构的带隙存在差异, 导带区域电子分布和弥散程度大于价带区域,局域性差. 五种SnO2晶体结构的价带部分约在-10 - 0 eV和-20 - -15 eV处, 主要贡献来自于O 2p、2s轨道. 光学性质计算表明, Pnam结构对紫外波段光的吸收最明显, 同时给出电子轨道跃迁规律.     

不同SnO2晶体结构的力学性能及电子结构

采用基于密度泛函理论(DFT)的平面波超软赝势法,用广义梯度近似(GGA)PBE交换相关泛函,对高压相变产生五种不同 SnO2晶体结构的电子结构和力学性质进行了第一性原理计算.计算结果表明,Pnam型SnO2的形成相对困难,体模量较大,Pbca和Pnam型SnO2的维氏硬度值相差不明显.不同晶体结构的带隙存在差异,导带区域电子分布和弥散程度大于价带区域,局域性差.五种SnO2晶体结构的价带部分约在-10-0 eV和-20--15 eV处,主要贡献来自于O2p、2s轨道.光学性质计算表明,Pnam结构对紫外波段光的吸收最明显,同时给出电子轨道跃迁规律.     

Structures of N-methylnicotone and Py-N-methylmetanicotone

Summary The structures of N-methylnicotone and Py-N-methylmetanicotone are, respectively, 1-methyl-5-(1-methyl-2-pyrrolidinyl)-2(1H)-pyridone and 1-methyl-5-(4-methylamino-1-butenyl)-2(1H)-pyridone.     

Structures of dictysine and dehydrodictysine

From the results of an x-ray structural analysis of free dictysine it has been established that dictysine is an alkaloid of the denudatine type with anα, β, γ-triol system at C₁₅, C₁₆, and C₂₀. The structures of the acetonides of dictysine and dehydrodictysine formed from dictysine and dehydrodictysine, respectively, in the process of separating the combined alkaloids, have been shown.     

Synthesis and Structures of Polyphenylphenanthrenes

1,2,3,4,5,6,7,8-Octaphenylphenanthrene ( 4 ) and decaphenylphenanthrene ( 5 ) were prepared by very short syntheses (two or three steps) from tetraphenylfuran and polybrominated benzene derivatives. The X-ray structures of compounds 4 and 5 show them to be quite crowded, with the phenanthrene cores twisted by about 40° due to the clash of the C4 and C5 phenyl groups. Compound 4 was resolved by chromatography on a chiral support, and its free energy of activation for racemization was determined to be 24.6 kcal mol⁻¹ at 40 °C. Computational studies indicate that compound 5 has a racemization barrier approximately 6 kcal mol⁻¹ lower than 4 , and thus 5 would not be configurationally stable at room temperature.     

Structures of decorine and delcoridine

In order to confirm the structures of the alkaloids delcorine and delcoridine (O-demethyldelcorine) suggested previously, a direct passage has been performed from delcoridine to delcorine and from delcorine to delphatine. It has been shown that the α configuration of C₁ - OCH₃ previously suggested for delcorine and delcoridine is incorrect — it should be β.     

Structures and properties of Ormosils

Organically modified silicates (ORMOSILS) can be conveniently divided into three types. In Type A, the organic such as a dye, is mixed into the sol-gel liquid solution. On gelation, the organic is trapped in the gel. In Type B, a porous oxide gel is first formed and the porosity and pore size controlled by heating. An organic is then impregnated into the pores of the gel. In Type C, the organic is added to the oxide gel liquid solution but unlike Type A, a chemical bond is formed between the oxide and the organic. Types A, B and C can further be mixed. Together, these various types of ORMOSILS offer a very wide spectrum of chemistry, structures and applications. They constitute a new family of exciting materials with new scientific challenges and technical possibilities. A critical review will be presented on these ORMOSILS including structures, properties and applications.     

Structures and Syntheses of Carboranes

Following a discussion of bonding, the structures of the known carboranes of the clovo type and of the incompletely condensed types are described; the recently discovered carboranes with high carbon contents, such as tetracarbahexaborane (“boracarbane”) are also discussed. The preparation of carboranes from polyboranes and the possibility of obtaining organo carboranes from organoboranes are then described. Some rearrangements which take place within the carborane skeleton are also mentioned.     

Structures of cauferin and cauferidin

Summary Two new terpenoid coumarins have been obtained from the roots ofFerula conocaula Korov. and have been called cauferin and cauferidin.On the basis of chemical and spectral characteristics, the structure and relative configuration of cauferin represented by formula (I) and the structure of cauferidin represented by formula (II) have been suggested.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 327–331, May–June, 1978.     

Structures of fersin and fersinin

Two new compounds — fersin and fersinin — have been isolated from the neutral fraction of the total extractive substances from the roots ofFerula soongorica. Their structures have been established on the basis of chemical transformations and spectral characteristics.     

Structures of fersin and fersinin

Two new compounds — fersin and fersinin — have been isolated from the neutral fraction of the total extractive substances from the roots ofFerula soongorica. Their structures have been established on the basis of chemical transformations and spectral characteristics.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, FAX (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 504–506, July–August, 1994.     

Structures of dictysine and dehydrodictysine

From the results of an x-ray structural analysis of free dictysine it has been established that dictysine is an alkaloid of the denudatine type with an, , -triol system at C₁₅, C₁₆, and C₂₀. The structures of the acetonides of dictysine and dehydrodictysine formed from dictysine and dehydrodictysine, respectively, in the process of separating the combined alkaloids, have been shown.Institute of the Chemistry of Plant Substances, Academy of Sciences of Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 86–91, January–February, 1982.     

Structures of decorine and delcoridine

In order to confirm the structures of the alkaloids delcorine and delcoridine (O-demethyldelcorine) suggested previously, a direct passage has been performed from delcoridine to delcorine and from delcorine to delphatine. It has been shown that the configuration of C₁ - OCH₃ previously suggested for delcorine and delcoridine is incorrect — it should be .Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 621–623, September–October, 1981.