双-锌卟啉对DABCO分子识别的立体构象及其热力学研究

Molecular Recognition of Zinc Porphyrin Dimers to DABCO andCorresponding Thermodynamic Study

合成了系列不同长度以柔性侧链相连的ｐ/ｐ型双－锌卟啉配合物,用１Ｈ ＮＭＲ和ＵＶ－Ｖｉｓ研究了不同温度下该系列配合物与刚性双齿配体ＤＡＢＣＯ(１,４－二氮杂双环)的轴向配位反应,考察了侧链长度对双－锌卟啉与配体的分子识别能力影响．结果表明,主体分子双－锌卟啉可以对客体分子ＢＡＢＣＯ进行分子识别,合适长度的柔韧烷氧链可以调节主体分子的构象,使ＤＡＢＣＯ嵌入双卟啉两个卟啉环间空位中,形成锌卟啉－ＤＡＢＣＯ－锌卟啉三元夹心式配合物构象．探讨了配位反应中立体构象的变化过程,并测定了热力学参数．

A series of p/p type zinc porphyrin dimers covalently linked with a flexible chain are synthe-sized and characterized. The molecular recognition of zinc porphyrin dimers and corresponding monomer torigid nitrogenous bidentate ligand DABCO (1, 4-diazobicyclo[2,2,2]octane) are described in detail by 1HNMR and UV-Vis spectroscopy. DABCO can bind inside the cavities of porphyrin dimers and form aternary sandwich complex as the length of the alkoxyl chain is long enough and their molar ratio is suit-able. The thermodynamic parameters such as the equilibrium constants, stoichiometric numbers, and thecorresponding enthalpies and entropies of the binding behavior are also obtained by UV-Vis spectroscopy.