偶氮染料分子的电子结构与生物降解活性（Ⅱ）

通过ＭＮＤＯ计算及相关实验结果,用取代基非定域活性概念分析了羟基、氨基及硝基在－Ｎ－Ｎ－上的电子效应,阐述了取代基影响偶氮键生物降解活性的电子结构机理,并提出将ＭＮＤＯ统计集成分析中的活性电荷ＱＡ作为关联偶氮键生物解活性的电子结构参数。     

偶氮染料分子的电子结构与生物降解活性(Ⅱ)-取代基非定域活性对偶氮键还原裂解的影响

通过ＭＮＤＯ计算及相关实验结果,用取代基非定域活性概念分析了羟基、氨基及硝基在—ＮＮ—上的电子效应,阐述了取代基影响偶氮键生物降解活性的电子结构机理,并提出将ＭＮＤＯ统计集居分析中的活性电荷ＱＡ（其值可反映原子在分子中的化学活性）作为关联偶氮键生物降解活性的电子结构参数     

N^4—取代缩氨基硫脲衍生物的合成

以Ｎ４－取代氨基硫脲与尿嘧啶－１－乙醛反应，合成了６种Ｎ４－取代氨基硫脲衍生物，并进行了抗菌活性测试。结果表明，当Ｎ４－取代基为对氯苯基（Ⅲ６）时，具有较高的抑制枯草杆菌活性，对八叠球菌、白色念珠菌、黄曲霉菌亦有一定活性。     

α—取代乙酰胺类化合物结构与除草活性的构效关系研究

分别研究了Ｎ，Ｎ－二取代－α－氯代乙酰胺类化合物及Ｎ，Ｎ－二取代－α－二硫代磷酰基之酰胺类化合物结构与除草活性的定量关系，结果表明，氮原子上取代基的大小对两类化合物的除草活性具有相同的影响，只是最适宜的疏水性不同，两类化合物可能具有相同的作用机制。     

1,4,2-二氮磷杂环戊-5-(硫)酮类化合物除草活性的构效关系研究

利用与自由能有关的取代基的物理化学参数,考察了1,4,2－二氮磷杂环戊－5－(硫)酮类化合物对除草活性的相关性.根据Hansch方程及多元回归分析,进行了结构与活性定量关系的研究,建立了较好的结构与活性相关式,预测出化合物的活性并得到实验证实.     

α－取代乙酰胺类化合物结构与除草活性的构效关系研究

分别研究了Ｎ，Ｎ－二取代－α－氯代乙酰胺类化合物及Ｎ，Ｎ－二取代－α－二硫代磷酰基乙酰胺类化合物结构与除草活性的定量关系。结果表明：氮原子上取代基的大小对两类化合物的除草活性具有相同的影响，只是最适宜的疏水性不同，两类化合物可能具有相同的作用机制。     

1,4,2—二氮磷环戊—5—（硫）酮类化合物除草活性的构效关系研究

利用与自由能有关的取代基的物理化学参数，考察了１，４，２－二氮磷杂环戊－５－（硫）酮类化合物对除草活性的相关性，根据Ｈａｎｓｃｈ方程及多元回归分析，进行了结构与活性定量关系的研究，建立了较好的结构与活性相关式，预测出化合物的活性并得到实验证实。     

O—乙基—N—异丙基（取代硫脲基）硫代磷酰胺酯类衍生物杀菌作用…

研究了一系列Ｏ－乙基－Ｎ－异丙基（取代硫脲基）硫代磷酰胺酯类化合物的杀菌活性，发现分子的活性中心在硫脲基上，其氮原子所连的取代基对活性有重要影响，采用取代基物理参数化合物对多种植物病菌的抑制活性，进行了结构与活性定量关系的研究，建立了较好的民性的盯关笥，预测出更高活性的化合物并得到实验证实。     

4—肟醚基喹唑啉类化合物的合成及其抗植物病毒TMV活性

４－氯喹唑啉与取代芳香肟在碱存在下进行亲核取代反应，合成了１７种新型肟醚基喹唑啉衍生物，并对其结构进行了表征。生物活性测试表明，部分化合物抗植物烟草花叶病毒活性超过抗植物病毒商品药剂２，４－二氧六氢－１，３，５－三嗪。     

电子效应对单取代苯定位效应和反应活性的影响

单取代苯的定位效应和反应活性主要受取代基的电子效应控制,列表总结了取代基的电子效应与定位效应和反应活性的关系,分析了烃基电子效应的特殊性,取代基具有-Ⅰ效应的普遍性。除卤素取代基外,探讨了共轭效应的方向对定位效应和反应活性的决定作用。     

偶氮染料分子的电子结构与生物降解活性(Ⅰ)——电荷分布对偶氮键还原裂解的影响

用量子化学MNDO方法计算了不同结构类型的偶氮染料分子的电子结构.与厌氧活性污泥对偶氮双键生物降解实验结果对照分析后发现,分子电子结构中,电荷分布的对称性对偶氮键生物降解活性有重要影响.并通过LUMO_lp(具有反应部位氮原子孤电子对特征的最低空轨道)及分子偶极矩阐述了电子结构与生物降解活性的关系.     

Effective charges on atoms in some phosphorus-containing compounds from XPS data

We have calculated the charges on the atoms in 19 phosphorus compounds of the type PX₃, PX₃P, YPX₃, PX₅ by solution of the system of equations connecting the chemical shifts E_b of the inner electronic levels of the atoms with charges qA on the atoms. We have shown that for their compounds, we cannot choose a universal constant of proportionality between E_b(P) and qp. The technique used in this work, taking into account the molecular potential, allows us to describe well the effect of substitutents on the charge of the phosphorus atom. We observe a correlation between the charges qp obtained within the given approach and the MNDO method.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 4, pp. 485–490, July–August, 1990.     

Quantum-chemical investigation of hydrogen bond in complexes of ice-forming reagents with water

The MNDO method has been used in a quantum-chemical calculation of the electronic structure of complexes IFR...H₂O and IFR...2H₂O (IFR is an ice-forming reagent — 1,3,5-trihydroxybenzene, 1,5-dihyrdoxynapthalene, or 2,6-dihydroxynaphthalene), with complete optimization of geometry. The calculated results are compared with data on the ice-forming activity and structural features of the crystals of these IFRs.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 1, pp. 41–47, January–February, 1992.     

含苯并五元环方酸衍生物的二阶非线性光学性质的理论研究

利用从头算HF/6-31G*方法对用苯并五元环取代的方酸衍生物体系SQ1～SQ15进行几何构型优化和电子结构计算. 以优化后的构型为基础, 应用ZINDO方法计算电子光谱. 同时应用从头算CPHF/6-31G*方法和半经验FF/AM1, FF/PM3, FF/MNDO等有限场方法计算了分子的二阶非线性光学系数β_μ. 研究几何结构、电子结构和前线分子轨道能与β_μ之间的关系, 为设计性能优良的有机非线性光学材料提供理论指导, 并对这四种计算方法的结果进行了比较.     

Pseudoelementverbindungen. II. Quantenchemische Untersuchungen an pseudoelementmodifizierten Nitrit-Ionen [EO2−nYn]− (E = N,C(CN); Y = C(CN)2)

Pseudoelement Compounds. II. Quantum Chemical Studies on Pseudoelement Modified Nitrite Ions [EO_2?nY_n]^? (E = N, C(CN); Y = C(CN)₂) The electronic structure and the ambidence of pseudochalcogen modified nitrite ions are discussed on the basis of a quantum chemical MNDO study in connection with structural, ESCA and ¹³C NMR data.     

Synthesis and Monoamine Oxidase Inhibitory Activity of 3-Substituted 5H-Indeno[1,2-c]pyridazines

The one-pot synthesis of nine 5H-indeno[1,2-c]pyridazines is described. These compounds are shown to be potent, reversible inhibitors of monoamine oxidase B (MAO-B) with little or no effect on monoamine oxidase A (MAO-A). Qualitative structure-activity relations indicate that the MAO-B inhibitory activity is strongly influenced by electronic and bulk properties of substitutents.     

Nucleophilic ring opening and the formation of saturated heterocycles. 11. Quantum-chemical investigation of the reactivities of aziridine and 2-methylaziridine in aminolysis reactions

The aminolysis of aziridine and 2-methylaziridine in the gas phase was investigated by the MNDO method. Using the Germer solvatone model, modified for the MNDO computational scheme, we studied the effect of a polar medium on the ammonolysis of aziridine and 2-methylaziridine. We showed that the most probable mechanism for the investigated reactions is an A_c2 mechanism; however, in polar media the realization of the A_a2 mechanism is possible in the case of sterically hindered amines. We found that the determining factor for the nucleophilic opening of aziridine rings is the three-dimensional structure of the nucleophile rather than its basicity.See [1] for communication 10.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7. pp. 905–912, July, 1991.We thank Yu. V. Puzanov for supplying us with sets of programs for the quantum-chemical calculations. We especially thank S. G. Koldobskii for his assistance in discussing the results of our calculations and providing us with an interpretation of the solvatone method for MNDO.     

The role of hydrophobicity in the Ames test. The correlation of the mutagenicity of nitropolycyclic hydrocarbons with partition coefficients and molecular orbital indices

A set of 20 nitropolycyclic aromatic hydrocarbons, whose mutagenicity has been determined in the Ames test, has been studied using octanol-water partition coefficients (P) as a measure of relative hydrophobicity and molecular orbital energies to account for variation in their electronic characteristics. A good structure-activity relationship was found using log P and ?_LUMO . The latter were taken from the results of ab initio calculations performed by Maynard, Pedersen, Posner, and McKinney [7] and were also calculated by the MNDO method. The dependence of mutagenicity on hydrophobicity was found to be similar to that observed for triazenes [2]. ?_LUMO values calculated by MNDO and STO -3G were found to be strongly correlated, and the role of hydrophobicity in correlating mutagenicity was not significantly affected by the molecular orbital model employed.