From Recent Publications
Morphosynthesis of Nanostructured Gold Crystals by Utilizing Interstices in Periodically Arranged Silica Nanoparticles as a Flexible Reaction Field
Nanostructured gold are promising as electrodes, catalysts, optical materials, and so on. Various nanostructured materials have been prepared by using templates, whereas the nanostructures are limited as inverse structure of the templates. In this study, periodically arranged silica nanoparticles were found to be a useful template which allows to form a dimpled gold nanoplate or a three-dimensionally ordered mesoporous gold by changing its structure during the deposition of gold.
Non-hydrolytic synthesis of branched alkoxysiloxane oligomers Si[OSiH(OR)2]4 (R=Me, Et)
Discrete alkoxysiloxane oligomers are ideal starting materials for Si-based materials having demanded compositions, structures, morphologies and functionalities. However, there are many limitations on their syntheses. In this study, novel synthetic route to discrete alkoxysiloxane oligomers directly from alkoxysilane was shown. We successfully synthesized Si[OSi(OR)2]4 (R = Me, Et), that can never achieved by classical method.
Anion Exchangeable Layered Silicates Modified with Ionic Liquids on the Interlayer Surface
Layered anion exchange materials are of considerable interest because of their uses as adsorbents of drugs, dyes, and biological molecules. However, the precise control of the anion exchangeable site was limited. In this report, cation exchangeable sites of SiOH/SiO− groups on octosilicate are stoichiometrically converted to anion exchangeable sites by immobilization of imidazolium salts, which is ionic liquid, on the interlayer surfaces. The obtained layered material possesses high AEC (ca. 2 mmol/g), and is applicable for use as a drug carrier with high accessibility, capacity, and durability.
Integrated structural control of cage-type mesoporous platinum possessing both tunable large mesopores and variable surface structures by block copolymer-assisted Pt deposition in a hard-template
Mesoporous metals are promising materials as catalysts, sensors, electrodes, and so on. Efficient diffusion in such materials can be achieved by introducing large mesopores several tens of nanometers in size, whereas their surface areas decrease. Then, we prepared a novel template containing silica nanoparticles and block copolymers. By using the template, metallic framework becomes aggregates of metal nanoparticles by the effect of block copolymers, which provides a mesoporous Pt both with large mesopores and high surface area.
Ferromagnetic Mesostructured Alloys: Design of Ordered mesostructured Alloys with Multicomponent Metals from Lyotropic Liquid Crystals
We have focused on synthesis of various kinds of highly ordered mesoporous metals via soft-templating method using lyotropic liquid crystals (LLCs) consisting of highly concentrated amphiphilic molecules. So far, functions of mesoporous metals have been less developed. In this study, we synthesized highly ordered mesostructured Ni-Co-Fe alloy particles with ferromagnetic properties. The ferromagnetic properties depended on the compositions of mesostructured framework which were tunable by changing that of LLCs. We proved that framework composition is one of important factors for possessing functions to mesoporous metals. （See also our review article: Y. Yamauchi and K. Kuroda, Chem. Asian J., 3, 664 (2008).）
Stepwise silylation of double-four-ring (D4R) silicate into a novel spherical siloxane with a defined architecture
Siloxane dendrimers can be regarded as finely designed silica nanoparticles. Trimethylsilylation of a triethoxysilylated derivative of doublefour-ring (D4R) silicate led to the formation of a novel crystalline spherical siloxane molecule containing a cubic D4R core. This bottom-up process provides a new pathway to prepare silica nanoparticles with well defined size, structure, morphology, and functionality.