Development of Synthetic Methods for New Porous Materials by the Conversion of Inorganic Layred Compounds into Three-dimensional Networks

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1) Reactions between a surfactant hexadecyltrimethylammonium ion (C_<16>TMA^+)and kanemite (NaHSi_2O_5・3H_2O) was studied with various C_<16> TMA^+/Si rations. If C_<16>TMA^+/Si was larger than 0.2, lamellar phase was obtained. Solid-state NMR showed that this phase contained Q^4 silicate species, indicating that this reaction was not topotactic intercalation one. When the reaction proceeded at ambient temperature, the lamellar phase at the intial stage contained no Q^4 silicate species, suggesting that the initial product was intercalation compound. Thus, it is assumed that the initially-formed intercalation compound was converted into a cross-linked structure during the reaction.2) The surface of a porous material derived from kanemite via folded-sheet mechanism was modified by using various silylating reagents. The surface was modified by the reactions with RMe_2SiCl in toluene under protective nitrogen atmosphere. IR,solid-state NMR and DTA showed the successful immobilization of RMe_2Si-groups via siloxane bonding. XRD analysis showed that the structure of the silicate was maintained during the surface modifications. The pore-size distributions indicate that the mean pore size decreased as the length of the alkyl chain increased, suggesting successful control of pore size by surface modification.