Application of Clay-Metal Complex Hybrid Films to Non-linear Optical Materials

本项目的目的是制备一种用于二次谐波产生（SHG）的粘土和金属配合物的超薄膜。蒙脱石粘土由于用作离子交换材料、催化剂和改性电极而引起了科学和技术的兴趣。其中一个突出的性质是极性或离子分子同时结合到层间空间（插层）。由于蒙脱石粘土层的两边是相同的，嵌入的分子自然会抵消任何取向的各向异性；例如，极性分子在相邻的位置以相反的方式定向，以抵消个别的偶极矩。在本项目中，我们采用了一种全新的方法，将人工分层应用于粘土矿物，可以制备一种具有非中心对称结构的新型插层化合物。根据该方法，单层两亲性钌（II）配合阳离子在一个亚相中与粘土颗粒进行了更多的杂化。带负电荷的粘土薄片被静电吸附在漂浮单层的底部。这样形成的杂化单层通过水平浸渍沉积到衬底上以制备多层薄膜。通过测量二次谐波产生（SHG），研究了多层LB薄膜的非中心对称性。结果表明，在杂化LB薄膜上成功地观察到SHG，显示出强度与层数的二次依赖关系。结果证实了整个Ru络合离子在粘土层间的排列顺序是不对称的。外消旋配合物与对映体离子混合LB膜的SHG也存在差异。上述项目是我们团队（北海道大学）和Schoonheydt教授团队（比利时鲁汶天主教大学）的密切合作完成的。我们相信，在研究工作中，相互的理解和密切的联系绝对是当前项目成功的关键。衷心感谢Schoonheydt教授和他的合作者。少

The purpose of the present project is to prepare an ultra-thin film of a clay and a metal complex for the use of second harmonic generation (SHG). Smectite clays have been of scientific and technological interest because of their use as ion-exchange materials, catalysts and modified electrodes. One of the outstanding properties is the simultaneous incorporation of polar or ionic molecules into interlayer spaces (intercalation). Since both sides of a layer in a smectite clay are identical, intercalated molecules naturally tend to cancel any orientational anisotropy; polar molecules, for example, orient in the opposite ways at the adjacent sites to cancel out individual dipole moments.In the present project, we take a completely a new approach, in which the application of artificial layering to clay minerals allows one to prepare a novel intercalation compound with non-centrosymmetric structures. According to the method, a monolayer of amphiphilic ruthenium(II) complex cations has been h … More ybridized with clay particles in a subphase. Clay platelets with the negative charge are adsorbed electrostatically onto the bottom of a floating monolayer. The hybrid monolayers thus formed are deposited onto a substrate by horizontal dipping to prepare a multilayered film.Non-centrosymmetricity of the multilayered LB film has been examined by measuring secondary harmonic generation (SHG). As a result, SHG was observed successfully from the hybrid LB films, showing the quadratic dependence of intensity on layer number. The results have confirmed that the whole Ru complex ions order in an asymmetric way between the clay layers. A difference in SHG was also found between the hybrid LB film of racemic complex ion and that of enantiomeric one.The above project has been accomplished with the close collaboration between our group (Hokkaido University) and Prof. Schoonheydt's grouy (Leuven Catholic University, Belgium). We believe the success of the present project absolutely lies in the mutual understanding and close connection although the research works. Sincere thanks are due to Prof. Schoonheydt and his collaborators. Less