Clay column chromatography for optical resolution: Selectivities of Lambda-[Ru(phen)(3)](2+) and Lambda-[Ru(bpy)(3)](2+) laponite columns towards 1,1'-binaphthol

1,1'-Binaphthol was resolved chromatographically on a column packed with Lambda-[Ru(phen)(3)](2+) and Lambda-[Ru(bpy)(3)](2+) laponite columns when the compound was eluted with methanol solvent. The elution order of 1,1'-binaphthol enantiomers was R --> S and S --> R for the [Ru(phen)(3)](2+) and Lambda-[Ru(bpy)(3)](2+) columns, respectively. From the temperature dependence of the retention time for each enantiomer, the difference of enthalpy of adsorption between the R- and S- enantiomers, -Delta H-R - (-Delta H-S), was obtained to be -2.7 and 5.3 kcal/mol for the Delta-[Ru(phen)(3)](2+) and Lambda-[Ru(bpy)(3)](2+) columns, respectively. The adsorption structures of 1,1'-binaphthol enantiomers were studied by the X-ray diffraction analyses of the powder samples of clay-Ru(II) complex-1,1'-binaphthol adducts. The stability of the binding of 1,1'-binaphthol was examined by the theoretical simulations based on the Monte Carlo method.