ESR EVIDENCE FOR AROMATIC FREE RADICAL COMPLEXES IN FRIEDEL-CRAFT''''S ALKYLATION

ESR study of the systems C_6H_6-AlCl_3-CHCl_3, C_6H_6-AlCl_3-CCl_4, C_6H_6-AlCl_3-CDCl_3 and C_6H_6-AlCl_3-CBr_4 is reported. We discovered that the four systems have a common free radical intermediate. The spectra were analyzed with the aid of a computer. The hyperfine coupling constant for the six magnetically equivalent protons (I=1/2) in the intermediate compound is α_H=2.10×10~(-4) T; and that for the two equivalent aluminiums is (I=2/5)α_(Al)=0.45×10~(-4) T. The possible structure may be visualized asAlCl_3←C_6H_6~(·+)→AlCl_3.We also determined the relative conductivity and temperature of the reaction as a function of reaction time for the two systems: C_6H_6-AlCl_3-CHCl_3 and C_6H_6-AlCl_3-CCl_4. These two plots exhibit synchronous changes. When the reaction was stopped, the conductivity was found to stay constant. These results suggest that the reactions might follow a free radical mechanism.     

四（甲醚撑）多β—二酮型开链冠醚键合离子色谱固定相的研究

把四（甲醚撑）多β－二酮型开链冠醚技到用氨丙基三乙氧基硅烷改性的硅胶小球上，制备出一种新型的开链冠醚键合离子色谱固定相。对其色谱特性进行了考察。用不同比例的甲醇／水作流动相，可对碱金属、碱土金属、过渡金属得到较好的分离。     

四甘酰双[二(对辛基苯)胺]PVC膜钡离子选择电极的制备和应用

钡离子选择电极的制备已有一些报道。以N,N,N′,N′-四苯基-1,11-二氧代-3,6,9-三氧杂十一烷二胺(即四甘酰双二苯胺,图1B)为中性载体,可制得稳定性好、寿命长的 PVC 膜钡离子电极。由于该电极受 pH 影响较大,抗 K~ 、Sr~(2 )的干扰能力不强,在应用时受到了较多的限制。考虑到增加中性载体的亲脂性有可能改善电极的性能,我们进行了改变四甘酰双二苯胺结构的研究工作。本文报告用合成的四甘酰双[二(对辛基苯)胺]制成的 PVC 膜钡离子选择电极的性能和应用。此种电极比之四甘酰双二苯胺,选择性有些改善,pH 影响显著减小。     

稀土苦味酸盐与TDD配合物的结构研究

合成出化学式为[Eu(pic)_3(TDD)]·2CH_3CN和[Y(pic)_3(TDD)](TDD=N,N,N＇,N＇-四苯基-3,6-二氧杂辛二酰胺)的配合物.晶体结构分析表明,TDD作为四齿配体连同-pic的配位O原子形成具有一定孔径的“类环状”配位结构.Eu配合物中半径较大的中心离子处于类环孔腔平面之下;而Y配合物中半径较小的中心离子处于环内.由于pic参与配位,使配合物结构随中心离子半径的变化变得更加敏感.