Abstract Since the pioneering work by Gosh and Bard discovering that the metal complexes adsorbed into a clay film were active electrochemically, many studies have been reported on the application of clay-modified electrodes (Gosh and Bard, 1983; Fitch et al., 1998 ). The following questions remain to be answered on the mechanisms of a clay modified electrode: (1) How different an adsorbed state is between electrochemically active and inactive species in a film? (2) How the layered structure of a clay film affects the mobility of a charge carrier? In order to settle the above problems, it is helpful to prepare a film with the uniform orientation of a clay microcrystalline. It may also be important to study the diffusion process by controlling the thickness of a film on the level of the number of a clay layer. In most measurements, a clay film has been prepared by casting or spin-coating an aqueous clay suspension. Accordingly a film is a few micrometer thick, consisting of few hundred clay layers. It is not very clear how these layers are organized in a film and how the organization affects the generation of a charge carrier and its transportation process. Although the classical Langmuir-Blodgett (LB) technique is a powerful approach to construct multilayer molecular assemblies (Gaines, 1966), the method unfortunately suffers from critical drawbacks such as mechanical weakness and sensitivity to contaminants. If a rigid inorganic layer is incorporated in such a LB film, however, it is expected that the film may acquire mechanical strength. Moreover the method

Abstract A silica gel coated with a film of Λ-Ru(phen) 3 2+ -montmorillonite (phen = 1, 10-phenanthroline) was used as a packing material in high-performance liquid-column chromatography. The resolution of Co(acac) 3 (acac = acetyl-acetonato) was studied by varying the flow-rate, the component of an eluting solvent, and the temperature of the column. The column showed remarkable resolution efficiency compared with known column materials, such as natural and synthetic organic polymers. The mechanisms of chirality recognition were interpreted in terms of the intermolecular stacking of Co(acac) 3 with pread-sorbed Λ-Ru(phen) 3 2+ either on the external surface or in the interlayer space of the clay film. The column also resolved a wide variety of organic compounds, some of which are key molecules in asymmetric syntheses, such as 2, 2′-binaphthol and phenyl alkyl sulfoxides.