16415-13-7Relevant articles and documents
Self-assembly of designed oligomeric siloxanes with alkyl chains into silica-based hybrid mesostructures
Shimojima, Atsushi,Liu, Zheng,Ohsuna, Tetsu,Terasaki, Osamu,Kuroda, Kazuyuki
, p. 14108 - 14116 (2005)
A novel self-assembly route to ordered silica-organic hybrids using well-defined siloxane oligomers with alkoxy functionality and covalently attached alkyl chains has been investigated. Various hybrid mesostructures were obtained by hydrolysis and polycondensation without the use of any structure-directing agents. The oligomers 1(Cn), having an alkylsilane core and three branched trimethoxysilyl groups, formed highly ordered lamellar phases when n = 14-18, while those with shorter alkyl chains formed cylindrical assemblies, slightly distorted two-dimensional (2D) hexagonal structures (n = 6-10), and a novel 2D monoclinic structure (n = 12). Furthermore, the mixtures of 1(Cn) with different chain lengths yielded well-ordered 2D hexagonal phases, possibly due to the better packing of the precursors. The hybrids consisting of cylindrical assemblies were converted to ordered porous silica with tunable pore sizes upon calcination to remove organic groups. The liquid-state 29Si NMR analysis of the hydrolysis and polycondensation processes of 1(Cn) revealed a unique intramolecular reaction yielding primarily the oligomer with a tetrasiloxane ring which is a new class of amphiphilic molecule having both self-assembling ability and high cross-linking ability. We also found that the mesostructure (lamellar or 2D hexagonal) was strictly controlled by varying the number of siloxane units per alkyl chain. These results provide a deeper understanding of the present self-assembly process that is strongly governed by the molecular packing of oligosiloxane precursors.
Rh(pph3)3cl/tetrakis(dialkylamino)phosphonium salts as thermoregulated and recyclable catalytic system for hydrosilylation reaction
Wang, Diliang,Li, Jiayun,Peng, Jiajian,Bai, Ying,Lai, Guoqiao
experimental part, p. 2258 - 2266 (2012/03/27)
Eleven tetrakis(dialkylamino)phosphonium salts have been prepared and were used as "soft" catalyst supports for the hydrosilylation reaction of styrene with triethoxysilane catalyzed by Rh(PPh3)3Cl. Among the Rh(PPh3)3Cl/tetrakis(dialkylamino)phosphonium salts tested, the best catalytic activity and selectivity in favor of the β-adduct were obtained when {[(C4H9) 2N]3[(C8H17)2N]P}PF 6 was used as the support, and Rh(PPh3)3Cl/ {[(C4H9)2N]3[(C8H 17)2N]P}PF6 catalyst system can be reused more than 10 times without noticeable loss of catalytic activity and selectivity. Copyright Taylor & Francis Group, LLC.
CARBON-SILICON BOND CLEAVAGE OF ORGANOTRIALKOXYSILANES AND ORGANOSILATRANES WITH m-CHLOROPERBENZOIC ACID AND N-BROMOSUCCINIMIDE. NEW ROUTE TO PHENOLS, PRIMARY ALCOHOLS AND BROMIDES
Hosomi, Akira,Iijima, Susumu,Sakurai, Hideki
, p. 243 - 246 (2007/10/02)
Alkyl- and aryltriethoxysilanes undergo oxidative carbon-silicon bond cleavage smoothly with m-chloroperbenzoic acid (MCPBA) to afford the corresponding alcohols.Silatranes similarly gave alcohols and bromides with MCPBA and N-bromosuccinimide, respectively.
