Theoretical Study on Enol-keto Tautomerism of α-Fluorine-β-diketones

1 INTRODUCTION β-diketones are a class of high functional com- pounds with outstanding optical, electric and magne- tic properties[1], and the negative ion may act as an excellent chelating agent. Hall[2] have studied β-di- ketone/metal ion complexes and indicated that the ability of combination correlates with the keto-enol distribution in solution. The enol-keto equilibrium existing in β-diketones has been extensively studied over several decades[3~9]. Burdett[10] have investiga- ted…     

2—取代苯氧乙硫基—5—吡唑基—1,3,4—恶二唑和1,ω—二（5—吡唑基—1,3, …

以５－吡唑基－１,３,４－恶二唑－２－硫酮为原料,利用相转移催化法,分别与２－溴乙基取代苯基醚和１,ω－二溴烷烃反应,合成了１１个标题化合物。用元素分析,＾１Ｈ ＮＭＲ和ＭＳ确定了它们的结构。初步的生物活性测试结果表明：有２个化合物具有杀菌活性,其中之一具有较好的杀虫活性。     

Crystal Structure of a Novel Compound： 1-Phenyl-3-ethyl-4-（salicylidene hydrazide）-propenylidene-pyrazolone-5

1 INTRODUCTION 4-Acyl pyrazolones and their derivatives, reported to behave as effective chelating and extracting rea- gents for many metal ions, not only play a key role in coordination compounds with wide applications in several fields, from new materials[1] to catalysts[2] as precursors for CVD in the microe-lectronic Indus- try[3] and as potential antitumourals[4], but also are the focus of research as potential antifungal agro- chemicals and widely used as antiviral, antipyretic anal…     

Synthesis and Crystal Structure of N-（1-Phenyl-3-methyl-4-benzal-pyrazolone-5）-furoic Hydrazide

1 INTRODUCTION In recent years, investigations on the com- pounds containing hydrazide or hydrazone moieties have been increased considerably because of their potentially biological activities, especially as poten- tial inhibitors for many enzymes[1～5]. The presence of weak molecular interactions such as hydrogen- bonding controls the conformational and structural features which are important to the drug action[6, 7]. We have synthesized the photochromic compounds of pyrazolone thiosemi…     

The Geometry, Vibrational Frequencies and Thermodynamic Properties of Naphthalene Based on ab initio Calculation

采用ａｂｉｎｉｔｉｏ方法，在ＨＦ／６３１Ｇ水平下计算了萘的几何构型和振动频率．计算所得几何构型和转动惯量与实验结果相符良好．计算所得振动频率平均比实验结果大９．５％左右；经校正（校正系数０．９０５）的计算频率与实验结果很接近．用校正后的频率计算所得不同温度下的热力学性质如标准熵、标准热容等与实验结果相吻合．     

Microwave-assisted Synthesis and Crystal Structure of 3-Acetamido-1-phenyl-4-（2,6-dichloro）benzylidene-5-pyrazolone

The title compound,3-acetamido-1-phenyl-4-(2,6-dichloro)benzylidene-5-pyrazolone(C18H13Cl2N3O2,Mr = 374.21),has been synthesized by one-step condensation of 2,6-dichloroben-zaldehyde with acetic anhydride and 3-amino-1-phenyl-5-pyrazolone under microwave irradiation.The compound was characterized by means of IR and 1H NMR.Its crystal and molecular structure were determined by X-ray diffractometry.It belongs to the orthorhombic system,space group Pbca,with a = 12.5312(13),b = 8.5495(9),c = 31.110(3) ,V = 3332.9(6) 3,Z = 8,Dc = 1.492 g/cm3,λ = 0.71073 ,μ(MoKα) = 0.407 mm-1,F(000) = 1536,the final R = 0.0394 and wR = 0.0984.A total of 15894 reflections were collected,of which 3630 were independent(Rint = 0.0362).There exist three planes in the molecular structure.X-ray analysis reveals that the dihedral angles between planes 1 and 2,1 and 3 and 3 and 2 are 80.89,74.29 and 20.57°,respectively.     

Influence of Pretreatment Conditions on Methane Aromatization Performance of Mo／HZSM—5 and Mo—Cu／HZSM—5 Catalysts

Mo/HZSM-5 is a good catalyst for methane aromatization, and the reaction performance of Mo/HZSM-5 and Cu modified Mo/HZSM-5 catalysts under various pretreatment conditions has been studied. The results indicate that the catalyst presented a distinguished catalytic activity, benzene selectivity and a high stability when the bed temperature was raised in N2 atmosphere.     

Synthesis and Crystal Structure of 1-（2,6-Dichloro-4-nitrophenyl）-5-amino-4-cyanopyrazole

The crystal structure of 1-（2,6-dichloro-4-nitrophenyl）-5-amino-4-cyanopyrazole （C10H10Cl2N5O2, Mr = 298.09） has been determined by single-crystal X-ray diffraction. It crystallizes in the triclinic system, space group P1^- with a = 8.1258（10）, b = 8.6460（10）, c = 10.0214（12） A, α = 68.986（2）, β = 71.598（2）, γ = 85.181（2）°, V = 623.26（13） A3, Z = 2, Dc = 1.588 g/cm^3,μ = 0.525 mm^-1, F（000） = 300, R = 0.0613 and wR = 0.1524 for 1890 observed reflections, and the extinction coefficient = 0.010（5）. The crystal structure is stabilized by N-H...N hydrogen bonds.     

Synthesis and Crystal Structure of 5-Methyl- 2-phenyl-4-[（2-p-bromophenylamino）-furylmethylene]-3（2H）-one

A novel 4-heterocyclic acylpyrazolone-based Schiff base compound 5-methyl- 2-phenyl-4-[（2-p-bromophenylamino）-furylmethylene]-3（2H）-one （C21H16N3O2Br） has been synthesized by the reaction of 1-phenyl-3-methyl-4-（α-furoyl）-pyrazolone-5 （HPMαFP） and p-bromoaniline. Elemental analysis, IR spectra and X-ray single-crystal diffraction were carded out to determine the composition and crystal structure of the compound. Crystal data： triclinic system, space group P1^-, a = 9.0936（3）, b = 9.8067（4）, c = 11.6863（4） A, α = 102.512（10）, β = 90.9630（10）, γ = 114.327（10）°, Mr= 422.28, Z= 2, F（000） = 428.0, V= 920.46（11）A^3, Dc = 1.524 g/cm^3,μ = 2.254mm^-1, R = 0.0476 and wR = 0.1318 for 9389 independent reflections （Rint = 0.0122） and 3281 observed reflections （I 〉 2σ（I））. Structural analysis indicates that the compound exists in an amine-one form.     

苯甲酰-1,3-环己二酮类化合物互变异构的理论计算

对苯甲酰-1,3-环己二酮的各异构体进行了HF/6-31G＊水平的几何优化,然后对能量低的三酮式和2个顺式烯醇式异构体进行了更广泛的计算,探讨了计算方法、基组大小对异构体相对稳定性的影响。在此基础上,对该类化合物的互变异构化平衡常数、能垒进行了计算,在平衡常数的计算中充分考虑了溶剂的影响并结合实验结果进行了分析。最后,对有代表性的苯环2-位取代衍生物进行了计算,发现互变异构自由能与其HPPD酶抑制活性间存在着较好的相关关系。     

氮的四原子簇合物的从头算研究

在4－31G基组水平上，对氮的四原子簇合物：N42+，N4和N24-做了从头算研究．几何优化和振动分析表明：N24+，N4能量最低的构型分别为直线的D∞h结构和平面的D2h结构，N24-则为D4h结构，并将氮与磷的四原子簇合物做了比较．     

2-羟基咪唑在气相和水中的异构平衡和质子迁移的从头算计算和Monte Carlo模拟

采用从头算方法在MP2/6-31＋G^*水平上研究了2-羟基咪唑分子在孤立分子和一水合物的异构体的相对稳定性和可能的质子迁移反应, 分析了一个水分子的参与对2-羟基咪唑分子异构体的相对稳定性和质子迁移速率的影响, 采用Monte Carlo模拟方法研究了反应体系在水溶液中反应的溶剂化效应. 结果表明: 2-羟基咪唑分子的孤立分子和一水合物的最稳定异构体相同, 都为酮式. 直接质子迁移反应在水溶液中活化能垒有轻微增加, 但产物能量得到降低; 水助催化质子迁移反应在水溶液中的活化能垒和产物能量都得到明显降低. 综合气相和水相的计算结果, 2-羟基咪唑水助催化的质子迁移反应较易进行, 且在水溶液中进行容易, 可以很容易被实验观察到.     

钒(Ⅴ)巯基苯酚双齿配合物从头算研究

运用Ｇ９４Ｗ量子化学程序包,采用ＬＡＮＬ２ＤＺ基组,对钒与Ｈ２ｍｐ（ｏ－巯基苯酚）形成的双齿配合物结构单元Ｖ（ｍｐ）３ｎ－（ｍｐ＝ＯＣ６Ｈ４Ｓ２－,ｎ＝１,２）进行从头算研究．探讨这些配合物结构单元的稳定性、分子轨道能量、原子净电荷布居规律以及一些前沿分子轨道的组成特征等,为过渡金属双齿配合物的合成、分子组装分析及其在酶和蛋白质中的活性部位研究提供理论参考．     

反式-5,1O,15-三芳基-5,1O,15-三羟基-1-氢-三苯并[a,f,k]三茚的合成与从头算结构分析

合成了两个具有三个羟基的新型主体分子反式－5,10,15－三芳烃－5,10,15－三羟基－1－氢－三苯并[a,f,k]三茚（芳基分别为苯基和－萘基）,并通过从头算对其及其异构体的结构进行了分析,结果发现当芳基为苯基时,其顺式异构体分子印环中所有原子不完全处于共平面,而其反式异构体和1－萘基的顺反异构体均处于共平面。     

IR-LD Spectral Study and ab Initio Calculations of 1-Phenyl 3-Substituted Pyrazol-5-Ones

The stereo structural characterization of 1-phenyl-3-methyl (MPhP)- and 1-phenyl-3–phenyl (DPhP)-pyrazol-5-ones are achieved by means of a linear dichroic infrared spectral (IR-LD) spectroscopy of samples dissolved in nematic liquid crystal. The results, thus obtaining in both cases indicate a coplanar disposition of 1-phenyl substituent towards the pyrazole fragment, however, the benzene ring attached at 3-position in DFP is significantly deviated form the pyrazolone skeleton plane. Additionally the geometry parameters of both compounds are estimated by ab initio calculations using 6-31G** basis set on Hartee-Fock level of theory. The predicted stereo structure confirms the results achieved by the IR-LD spectral study that is in a good agreement with the X-ray data of the discussed pyrazol-5-ones derivatives.     

Synthesis of Derivatives of Pyrazolin-1H-3-ones from 2′-N-Substituted Monohydrazides of Cyclohexenedicarboxylic Acids

2-(6-Aryl-4-methylcyclohex-3-enecarbonyl)-4-ethoxycarbonylpyrazolin-1H-3-ones have been synthesized from 2′-N-(2,2-diethoxycarbonylvinyl)monohydrazides of 6-aryl-4-methylcyclohex-3-ene-1,1-dicarboxylic acids by boiling in DMF, pyridine, or toluene in the presence of potassium carbonate. Under analogous conditions, but without potassium carbonate, 2′-N-substituted hydrazides of cyclohexenecarboxylic acids are obtained. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1007–1011, July, 2005.     

On the tautomerism of 1-phenyl-3-substituted-pyrazol-5-ones and their photoinduced products — experimental and theoretical UV spectral analysis

A detailed experimental and theoretical UV-spectral analysis of the tautomeric forms of 3-methyl-1-phenyl pyrazol-5-one and 1,3-diphenyl pyrazol-5-one as well as of the UV-irradiated photoinduced products of the latter compound were carried out. The experimental UV-spectra were compared with the theoretical ones obtained by CIS/6-31G**. Selected geometrical parameters of the different tautomers were estimated by ab initio calculations using the RHF/6-31G** level of theory and basis set, which have also been discussed with a view to the corresponding UV-results.     

5-氯四唑银配合物的 ab initio 研究

用ａｂｉｎｉｔｉｏＭＯ法计算了６种氯代四唑银的配合物模型，结果表明，π型配合物难以存在．在σ型配合物中银的配位使四唑环上单键增长、体系更不稳定．环Ｎ（２）（或Ｎ（３））原子较Ｎ（１）（或Ｎ（４））原子易于与金属成键；Ｎ（２）型配合物较Ｎ（１）型配合物稳定．预示５氯四唑银配合物将以２∶１（配体：金属原子）Ｎ（２）型为主．