聚呲咯的研究

本文研究了不同电化学氧化聚合条件下所得聚吡咯的红外光谱,X射线光电子能谱、元素分析、X射线衍射图及扫描电子显微镜图等。对聚吡咯的电导性、电导率的依赖性、化学结构及结晶性等进行了讨论。     

高效液相色谱二氮杂冠醚键合相的合成及性能研究

本文报道在硅胶表面进行固－液相反应，合成硅胶键合二氮杂冠醚高效液相色谱固定相。采用有机元素分析、热分析、红外光谱、金属离子的络合容量测定等对键合材料进行鉴定和表征，并对其色谱性能进行了研究。     

Controlled redox conversion of new X-ray-Characterized Mono- and dinuclear heptacoordinated Mn(II) complexes into di-micro-oxo-dimanganese core complexes

Two heptacoordinated Mn(II) complexes are isolated and X-ray characterized using the well-known tpen ligand (tpen = N,N,N',N'-tetrakis(2-pyridylmethyl)-1,2-ethanediamine): [(tpen)Mn(OH(2))](ClO(4))(2) (1(ClO(4))(2)) and [(tpen)Mn(micro-OAc)Mn(tpen)](ClO(4))(3).2H(2)O (2(ClO(4))(3).2H(2)O). Crystallographic data for 1(ClO(4))(2) at 110(2) K (respectively at 293(2) K): monoclinic, space group C2/c, a = 15.049(3) A (15.096(3) A), b = 9.932(2) A (10.105(2) A), c = 19.246(4) A (19.443(4) A), beta = 94.21(3) degrees (94.50(3) degrees ), Z = 4. Crystallographic data for 2(ClO(4))(3).0.5(C(2)H(5))(2)O at 123(2) K: triclinic, space group P, a = 12.707(3) A, b = 12.824(3) A, c = 19.052(4) A, alpha = 102.71(3) degrees, beta = 97.83(3) degrees, gamma = 98.15(3) degrees, Z = 2. Investigation of the variation upon temperature of the molar magnetic susceptibility of compound 2(ClO(4))(3).2H(2)O reveals a weak antiferromagnetic exchange interaction between the two high-spin Mn(II) ions (J = -0.65 +/- 0.05 cm(-)(1), H = -JS(1).S(2)). EPR spectra are recorded on powder samples and on frozen acetonitrile solutions, demonstrating the maintenance upon dissolution of the heptacoordination of Mn in complex 1 while complex 2 partially dissociates. Electrochemical responses of complexes 1 and 2 are investigated in acetonitrile, and bulk electrolyses are performed at oxidative potential in the presence of various amounts of 2,6-lutidine (0-2.65 equiv per Mn ion). The formation from either 1 or 2 of the mixed-valent complex [(tpen)Mn(III)(micro-O)(2)Mn(IV)(tpen)](3+) (3) is established from mass spectrometry and EPR and IR spectroscopy measurements. When reaction is started from 2, formation of [(tpen)Mn(IV)(micro-O)(2)(micro-OAc)Mn(IV)](3+) (4) is evidenced from cyclic voltammetry, EPR, and UV-vis data. The Mn vs tpen ratio in the electrogenerated complexes is accurately controlled by the quantity of additional 2,6-lutidine. The role of tpen as a base is discussed.     

5-甲基-[(2E,6E)-3,7,11-三甲基-9-氧代十二碳二烯]苯醌和氢醌的首次全合成

以2-甲基对苯二酚和香叶基溴为起始原料, 经过酚羟基保护, 溴代, Li₂CuCl₄催化的芳基溴与Grignard试剂的偶联以及Julia偶联等一系列反应, 完成了裸鳃亚动物的代谢产物, 5-甲基-[(2E,6E)-3,7,11-三甲基-9-氧代十二碳二烯]苯醌(1)和氢醌(2)的首次全合成, 将1用NaBH₄还原, 得到(±)-3, (±)-3也是此类天然产物之一.     

(-)-（3S, 6R）-3, 6-羟基-10-甲基十一酸及其三聚体的全合成

以廉价易得的异戊基溴为起始原料,以烯丙基二异松莰烷基硼烷参与的不对称烯丙基化反应和Yamaguchi酯化反应为关键步骤,实现了对(-)-(3S,6R)-3,6-二羟基-10-甲基十一酸(总收率27.5％)及其三聚体(总收率24.5％)的不对称全合成。     

Electroinitiated cationic polymerization of styrene

A constant controlled current was passed through a solution of styrene in methylene chloride containing a tetraalkylammonium salt as supporting electrolyte. Reproducible rates of polymerization were initiated by the electrochemical techniques employed and the kinetics of the reaction were investigated. Sigmoidal curves of conversion versus time were observed. A kinetic relationship of the form In ([M₀]/[M]) = ½ Kt² was derived on the basis of simple assumptions regarding the mechanism and fitted the data accurately. The rate constants obtained were compared to others reported, and the influences of ion association on the values of the rate constants obtained are discussed. The reactions were decreased in rate by a reversal of polarity of the electrodes. However, the stoichiometry of the production of active centers and of their destruction was not ideal, in that each electron did not result in the initiation of a polymer chain.     

过冷熔体中枝晶生长的相场法数值模拟

利用相场法模拟了过冷纯金属熔体中的枝晶生长过程,研究了各向导性、界面动力学、热扩散和界面能对枝晶生长的影响.结果表明,热噪声可以促发侧向分支的形成,但不影响枝晶尖端的稳态行为;随着各向异性的增加,枝晶尖端生长速度增加,尖端半径减小;当界面动力学系数减小及在界面动力学系数小于1的条件下热扩散系数减小时,枝晶尖端生长速度随之减小,而尖端半径相应增大;界面能趋于增大枝晶尺度并保持界面在扰动下的稳定,界面能越大,形成侧向分支的趋势越小 关键词： 过冷 枝晶生长 相场法 数值模拟     

UH和UH_2分子的结构与势能函数

用相对论有效原子实势 (RECP)和密度泛函 (B3LYP SDD)方法研究了UH ,UH2 基态和低激发态的结构和势能函数 ,导出了分子的光谱数据 .结果表明 ,UH和UH2 的基电子状态分别为X4 Π和X3A2 ,离解能分别为 2 .886eV和5 .2 4 9eV ,UH2 具有C2v对称性 ,得到了UH和UH2 的几个不同的低激发态的结构与光谱数据 .应用多体项展式理论以及数字拟合方法 ,计算得到了UH分子和基态UH2 三原子分子的分析势能函数 ,该函数正确反映了UH和UH2分子的结构特征 ,可用于研究UHH的微观反应动力学 .     

新显色剂四(4-甲氧基-4-磺酸基苯基)卟啉与Fe~(3+)的高灵敏反应的研究与应用

本文提出以四 (4 -甲氧基 - 4 -磺酸基苯基 )卟啉 (p- OCH3TPPS4 )为显色剂 ,在 p H=3.5— 5 .5的条件下测定痕量铁的新体系 ,络合物最大吸收波长为 4 4 6nm,表观摩尔吸收系数ε=2 .0× 10 4 L· mol-1· cm-1,Fe3+ 在 0— 10 μg/ 2 5 m L 范围内符合比耳定律 ,应用本法测定花生仁皮中铁 ,回收率可达 95 .0 %—10 8.4 %