手性Salen Zn配合物的合成及对咪唑类、吡啶类客体的分子识别研究  

Synthesis and Molecular Recognition of Chiral Salen Zn with Imidazoles and Pyridines

作　　者：张玉玲[1] 阮文娟[1] 李瑛[1] 南晶[1] 朱志昂[1] 

机构地区：[1]南开大学化学系,天津300071

出　　处：《化学学报》2003年第2期186-191,共6页Acta Chimica Sinica

基　　金：国家自然科学基金 (No.2 0 1 71 0 2 4 );教育部留学回国人员科研基金资助项目

摘　　要：合成并表征了手性Salen配体 1及其Zn配合物 2 .详细讨论了配体及配合物的电子光谱和圆二色光谱性质 .用紫外 -可见光谱滴定法测定了主体 2与 4种咪唑、5种吡啶客体轴向配位反应的平衡常数 ,研究了主体分子 2的分子识别行为 .实验结果表明 :各种客体的缔合常数 ,咪唑类按K(Im) >K( 2 MeIm) >K(SMIm ) >K(EMIm)顺序递减 ;吡啶类按K(Py) >K( 3 Py) >K( 3,5 Py) >K( 2 ,4 Py) >K( 2 ,4,6 Py)顺序递减 .测定了识别过程的ΔrG m ,ΔrH m ,ΔrS m ,发现该反应是放热、熵减小的过程 .采用分子力学的方法考察了主客体的最低能量构象 ,并对该构象进行量子化学计算 。Chiral salen 1 and chiral salen Zn complex 2 were synthesized and characterized. The electronic spectra and circular dichroism spectra properties were discussed. By method of UV-vis spectrophotometer technique, the equilibrium constants of axial coordination reaction were measured between complex 2 and series of imidazoles or pyridines. The molecular recognition of the host 2 was studied. The results show that the equilibrium constants decrease in the orders of K(Im)>K(2-MeIm)>K(SMIm)>K(EMIm) (imidazoles) and K(Py)>K(3-Py)> K(3,5-Py)>K(2,4-Py)>K(2,4,6-Py) (pyridines). The thermodynamic parameters Δ rG  m, Δ rH  m and Δ rS  m of the recognition process were determined. It is found that the reaction is an exothermic process with entropy decreasing. In addition, the conformations with minimal energy of each host-guest molecular system were sought by molecular dynamics method. Quantum chemical calculations were performed on these conformations to explain the experimental data. A model of the recognition mechanism was constructed.

关 键 词：手性Salen配合物 锌 合成 咪唑 吡啶 分子识别 量子化学计算 

分 类 号：O641.4[理学—物理化学]