Study on Liquid-Liquid Interfacial Dynamics of Molecular Recognition System by Total Reflection Laser-Induced Thermal Lens.

液-液界面的微观信息在分析化学和分离科学中占有重要地位。建立了一种用于溶剂萃取动力学研究的界面热透镜（TL）技术。在本报告中，该技术应用于离子结合反应，在苯-乙酸缓冲界面上形成Fe(II) - 4,7-二苯基- 1,10 -菲罗啉（DPP）配合物。采用全反射激发和泵浦（NdYAG脉冲激光器）-探针（红色二极管激光器）对准相结合的方式，吸附在界面上的配合物的薄TL效应可以直接表征配合物的形成。首先，用两亲性分子10-（1-芘）癸酸在己烷-磷酸盐缓冲溶液界面上展开来评价该技术的规格。响应与膨胀分子的量呈线性关系，最小可检测量为1.0 x 10^<-10> mol，约为1/100单层。时间分辨率为0.1秒，可以监测复杂地层的初始阶段。制备后界面TL信号逐渐增大，对应于界面形成和络合物形成的老化。界面络合物的形成速率与一级Fe（II）浓度成正比，而与DPP浓度无关。提出了两步机制；(1)界面老化随着DPP向界面吸附量达到恒定，(2)界面与水相Fe（II）形成络合物。为进一步研究，合成了具有分子识别能力的杯萼[4]，并测定了其光谱性质。热透镜信号的分析正在进行中。

The microscopic information about liquid-liquid interface is very important in analytical chemistry and separation science. A new interfacial thermal lens (TL) technique has been developed for the study on dynamics of solvent extraction.In this report, this technique applied to an ion-association reaction, the formation of Fe(II) - 4,7-diphenyl-1, 10-phenanthroline (DPP) complex at a benzene - acetate buffer interface. The thin TL effect of the complex adsorbed on the interface could directly present the complex formation by using a combination of total reflection excitation and pump (NdYAG pulse laser) - probe (red diode laser) alignment. At first, an amphiphilic molecule, 10-(1-pyrene) decanoic acid, expanded at a hexane - phosphate buffer solution interface was used to evaluate the specification of this technique. A response is linear to amounts of the expanded molecule and a minimum detectable amount is 1.0 x 10^<-10> mol corresponding about 1/100-monolayer. A time resolution is 0.1 second, which can monitor an initial stage of the complex formation. After the preparation of the interface TL signal increased gradually corresponding to the aging of the interface formation and the complex formation. The interfacial complex formation rate was proportional to the first order of Fe(II) concentration but did not vary with the DPP concentration. Two-step mechanism is proposed ; (1) the interface aging with an adsorption of DPP to the interface up to a constant amount, (2) the interfacial complex formation with Fe(II) from aqueous phase.For further researches, Calix[4]arenas with molecular recognition ability were synthesized and those spectroscopic properties were measured. Analysis of the thermal lens signal is in progress.