Search

application/pdf, 論文(Article), The outer surface of mesoporous silica (MCM-41) particles was modified with ssDNA attached with FAM (fluorescent moiety) and gate control of the pores was investigated. Infrared spectra confirmed the successful modification of MCM-41 with the ssDNA via 4 synthetic steps. To close the pore gate, the surface ssDNA was hybridized with linker ssDNA having complementary base sequence on both ends. The pore gate was then opened again by hybridization with the ssDNA having complementary base sequence only on one end and BHQ-1(fluorescence quencher) on the other end. The gate opening process was confirmed by observing the fluorescence quenching of the FAM on the surface-modified ssDNA caused by the BHQ-1.

Several new synthetic organic reactions using silica gel and mesoporous silica were developed: 1)Nitroaldol reactions in the presence of a catalytic amount of amines using silica gel and mesoporous silica, 2) the addition of hydrogen halides to alkenes using silica gel, and 3) Self-Aldol reactions of highly volatile aldehydes using silica gel.

Mesoporous silica was synthesized using the geothermal water from the Onuma geothermal power plant in Akita Prefecture, Japan. Cetyltrimethylammonium bromide (CTAB) was reacted with geothermal water at a temperature of 90℃, with a total silicic acid concentration of 475 ppm (SiO_2) at pH 7, pH 8, pH 9, and pH 10 for 30 min. The total silicic acid concentration in the solution after formation of mesoporous silica at pH 9 was reduced to under 300 ppm. By calcining of the product at 550℃, mesoporous silica with pore sizes of about 2.8 nm and a specific surface area of 919 m^2/g was formed. The monosilicic acid in geothermal water plays an important role in the formation of mesoporous silica.

界面活性剤薄膜にテトラエトキシシラン（TEOS）蒸気を接触させると、TEOS蒸気が膜に浸透し、シリケート/界面活性剤の複合体が形成される。本稿では、蒸気浸透法によるメソポーラスシリカ薄膜の合成について解説する。また、高濃度のリン酸基を含有したシリカ薄膜の合成とその高いプロトン伝導性について紹介する。, 特集：メソポーラス物質の新展開

代表的なメソポーラスシリカとして知られるTi-HMS, MCM-41そしてFSM-16を有機合成反応における反応促進剤として活用することを試みた。ルイス酸サイトを有するTi-HMSが接触還元条件下,選択的に水酸基の脱ベンジル化反応を加速することを見出した。 MCM-41が水酸基の保護基として知られるt-butyldimethylsilyl (TBS)基存在下,triethylsilyl (TES)基を選択的に脱保護できることを見出した。 FSM-16がα-ハイドロキシカルボン酸の酸化的光脱炭酸反応やアリールメチルハライドやアリールメチルアルコールの光酸化反応,スチレン類の酸化開裂反応等幾つかの光反応を促進することを見出した。, Ti-HMS, MCM-41 and FSM-16 which are typical hexagonal mesoporous silica, were investigated for use as a promoter for organic synthesis. Ti-HMS, which possesses Lewis acid sites, was found to accelerate deprotection of the benzyl group, which is a typical protecting group of the hydroxyl group, selectively under hydrogenolytic conditions. MCM-41 proved to deprotect the triethylsilyl (TES) group, which is a typical protecting group of hydroxyl group, selectively and easily in the presence of t-butyldimethylsilyl (TBS) group. FSM-16 was found to accelerate several photo-reactions such as oxidative photodecarboxylation of α-hydroxy carboxylic acid, oxidation of arylmethylhalides and arylmethylalcohols, and oxidative cleavage of styrenes.