Crystal Structures of Twisted Di(2-Pyridyl)ketone and Planar Azo-di(2-Pyridine) and Their Discussion Based on PM3 Enthalpy Hypersurfaces for the Isoelectronic Molecules

Single crystal structure determinations prove the two pyridine substituents in di(2-pyridyl)ketone (H₄C₄NC)₂C=O to be twisted out of the carbonyl skeleton plane by torsion angles (OCCN) of 41° and –163°, in contrast to their planar arrangement in azo-di(2-pyridine) H₄C₄NC)-N=N-(CNC₄H₄). In order to rationalize the surprising difference between the two isoelectronic molecules, approximate PM3 enthalpy of formation hypersurfaces have been calculated for each of the two ring torsions, which are assumed to be the dominant ones among the 3N – 6 = 60 degrees of freedom. For both the ketone and the azo derivative, global minima are calculated, the torsion angles of which deviate from the crystal structure results, and, therefore, support the assumption that both the experimentally determined twisting of di(2-pyridyl)ketone as well as the flattening of azo-di(2-pyridine) might be affected by the crystal packing.     

铜(Ⅱ)-4-(喹啉-8′-甲基)-1,4,7,10-四氮杂环十三烷-11,13-二酮-α-氨基酸或5-取代邻菲罗啉两类三元配合物的稳定性研究

用 p H法在 (2 5.0± 0 .1 )℃ ,I=0 .1 mol· dm-3 KNO3 条件下 ,测定 Cu( ) - 4 - (喹啉 - 8′-甲基 ) - 1 ,4,7,1 0 -四氮杂环十三烷 - 1 1 ,1 3-二酮 -α-氨基酸或 5-取代邻菲罗啉两类三元配合物的稳定常数 ;研究了带甲基喹啉侧基大环多胺配体与 Cu( )离子的配位能力、配位方式 ;发现这两类三元体系配合物有特殊的稳定性 ;而且它们的稳定性与配体α-氨基酸及 5-取代邻菲罗啉酸碱强度之间的直线自由能关系的变化趋势相反 ;探讨了 Cu( )和 5-取代邻菲罗啉之间的 d- p反馈π键及其取代基 Hammett诱导效应的关系。     

N,N''''-硝基苯酰基取代苯酰氨基硫脲的合成与生物活性

酰氨基硫脲类化合物不仅具有广谱抗菌性能 ,还具有极好的杀虫和植物生长调节活性 [1～ 3] ,因而引起许多国内外学者对硫脲类化合物的合成及其化学结构与生物活性关系方面的研究 [4～ 8] .为了进一步研究不同的取代基团对此类化合物生物活性的影响 ,作者用硝基苯酰基异硫氰酸酯与芳基酰肼加成制得相应的 N ,N -硝基苯酰基取代苯酰氨基硫脲 ( ) ,并初步测定了它们抑制大肠杆菌和枯草杆菌生长的生物活性 .这些化合物尚未见文献报道 .Ar— COCl KSCN Ar—CONCS a～ cAr CONHNH2 ( 1 ～ 7) Ar—CONHC( S) NHNHCOAr Ar:a.o-N…     

Kinetics and mechanism of the interaction of DL-methionine with cis-diaquaethylenediamine platinum(II) perchlorate in aqueous medium

The kinetics of the interaction of DL-methionine with [Pt(en)(H2O)2]2+ have been studied spectrophotometrically as a function of [Pt(en)(H2O)22+], [DL-methionine], PH and temperature. The reaction proceeds via a rapid outer sphere association followed by two slow consecutive steps having first order dependence on the aqua ion and methionine concentrations. Activation parameters have been evaluated using the Eyring equation. The low H1 (15.6 kJ mol–1) and large negative value of S1 (–230 J K–1 mol–1) as well as H2 (19.5 kJ mol–1) and S2 (–226 J K–1 mol–1) indicate an associative mode of activation for both the aqua ligand substitution processes in the two consecutive steps.     

微量元素叶面肥料中硼的测定

研究了在 pH 6 .5乙酸铵缓冲溶液中 ,硼与 3 甲氧基 甲亚胺H的显色反应条件 ,最大吸收在 4 2 0nm处 ,摩尔吸光系数为 8.1× 10 3,硼含量在 0～ 10 μg/ 10ml范围内符合比耳定律。用于微量元素叶面肥料中硼的测定 ,获得了与国标法一致的结果     

Extraction Kinetics of Rare Earth Elements with sec—Octyl—phenoxy Acetic Acid

ＩｎｔｒｏｄｕｃｔｉｏｎＩｔｉｓｗｅｌｌｋｎｏｗｎｔｈａｔｙｔｔｒｉｕｍｃａｎｂｅｕｓｅｄｉｎｍａｎｙｆｉｅｌｄｓ ,ｓｕｃｈａｓｍｅｔａｌｌｕｒｇｙ ,ｃｅｒａｍｉｃｓ ,ｌａｓｅｒｓａｎｄｅｌｅｃｔｒｏｎ ｉｃｓ ,ｅｓｐｅｃｉａｌｌｙｉｎｆｌｕｏｒｅｓｃｅｎｔｍａｔｅｒｉａｌｓｗｈｏｓｅｎｅｅｄｆｏｒｈｉｇｈｐｕｒｉｔｙｙｔｔｒｉｕｍｏｘｉｄｅｉｓｉｎｃｒｅａｓｉｎｇ .ＩｎＣｈｉｎａ ,ｔｈｅｒｅ ｓｏｕｒｃｅｏｆｙｔｔｒｉｕｍｉｓｒｉｃｈ ,ａｎｄｔｈｅｈｉｇｈｐｕｒｅｙｔｔｒｉｕｍｉｓｂｅ ｉｎｇｏ…     

Effects of ultrasonic irradiation in flow-injection systems

The effects of ultrasonic irradiation on transport and reactions in several flow-injection manifolds are described. The influences of ultrasound on the physical dispersion of the injected plug is considered. Its effects on systems involving homogeneous (catalytic and non-catalytic) and heterogeneous (liquid/liquid extraction, precipitation) reactions are critically evaluated. In general, greater sensitivity is obtained, especially for heterogeneous systems, slow reactions and low analyte concentrations. Finally, practical considerations and potential uses of the combination of ultrasonic irradiation with flow-injection analysis are discussed.     

Comparative study of measured and critically evaluated resonance intergral to thermal cross-section ratios. Part I

For 13 isotopes, the resonance integral to thermal crosssection ratio was studied. The results of two different methods, applied in two different laboratories, are compared. One method consists in a direct determination of I₀/π₀-values from Cd-ratio measurements, the other is based on the evaluation of literature data, using accurately determined k₀-factors from two irradiation channels with largely different thermal-to-epithermal flux ratios.     

Further Daphniphyllum Alkaloids from the Leaves of Daphniphyllum macropodum Miq.

Five new polycyclic Daphniphyllum alkaloids, macropodumines F ( 1 ) and G ( 2 ), 17‐oxoyuzurimine ( 3 ), and macropodumines H ( 4 ) and I ( 5 ), were isolated from the leaves of D. macropodum Miq ., collected in Sichuan Province, China. The structures and relative configurations of the new compounds – as well as of four known, related alkaloids – were elucidated on the basis of in‐depth spectroscopic and mass‐spectrometric analyses, by chemical derivatization, and by comparison of spectroscopic data with those of known compounds.     

4,4’-一氧二（苯胺灵）的合成和晶体结构

通过4,4’-一氧二（异氰酸苯酯）与异丙醇加成反应，合成标题化合物 4,4’-一氧二（苯胺灵）(Ⅰ) (C20H24N2O5, Mr=372.41)，并用X射线衍射、红外光谱、13C核磁共振、电子轰击质谱和元素分析对标题化合物进行表征. 晶体属于三斜晶系，空间群为P1晶体学参数为: a=0.85107(17), b=0.91164(18), c=1.45701(3) nm, α=80.44(3)°, β=85.25(3)°, γ=62.88(3)°, V=0.9922(3) nm3, Z=2, Dc=1.247 g•cm－3, μ(Mo Kα)=0.90 cm－1, F(000)=396.两个苯环平面之间的夹角为62.06° (0.06°). 晶体结构经全矩阵最小二乘法修正，最终偏离因子R=0.0520, wR=0.1434(对可观察点).此化合物应具有广谱的生物活性.