日本ゼオライト学会　刊行物 Publication of Japan Zeolite Association

Layered compounds possess interlayer nanospaces that incorporate various molecules, and they are useful for the potential applications in catalysis, adsorption, separation, and so on. In this paper, a novel surface modification method for layered compounds is reported. Tripodal ligands have three hydroxymethyl groups and one terminal functional group. They form a stable tridentate linkage with the surface hydroxy groups of brucite-type metal hydroxides and layered double hydroxides, consisting of various metallic elements because the tridentate linkage is formed by the structural matching between the hydroxymethyl groups of tripodal ligands and the surface hydroxy groups of the metal hydroxides. Using this method, hybrid magnesium hydroxide that can intercalate various organic molecules and can be exfoliated into nanosheets is obtained, even though conventional magnesium hydroxide does not have an intercalation ability. In addition, when layered double hydroxides were synthesized in the presence of the tripodal ligands, very small nanoparticles were obtained. The layered double hydroxide nanoparticles show improved anion exchangeabilities under ambient conditions without exclusion of CO₂, and they are used for rapid adsorption of aqueous anionic species because of their high dispersibility. They are also useful as ion-exchanger, catalyst precursors, and catalyst supports. Consequently, tripodal ligands are quite useful modifier for controlling brucite-type layered metal hydroxides by a generalized method.