16068-37-4Relevant articles and documents
Cyclization phenomena in the Sol-Gel polymerization of α,ω-bis(triethoxysilyl)alkanes and incorporation of the cyclic structures into network silsesquioxane polymers
Loy, Douglas A.,Carpenter, Joseph P.,Alam, Todd M.,Shaltout, Raef,Dorhout, Peter K.,Greaves, John,Small, James H.,Shea, Kenneth J.
, p. 5413 - 5425 (1999)
Intramolecular cyclizations during acid-catalyzed sol-gel polymerizations of α,ω-bis(triethoxysilyl)-alkanes substantially lengthen gel times for monomers with ethylene (1), propylene (2), and butylene (3) bridging groups. These cyclization reactions were found, using mass spectrometry and 29Si NMR spectroscopy, to lead preferentially to monomeric and dimeric products based on six- and seven-membered disilsesquioxane rings. 1,2-Bis(triethoxysilyl)ethane (1) reacts under acidic conditions to give a bicyclic dimer (5) that is composed of two annelated seven-membered rings. Under the same conditions, 1,3-bis(triethoxysilyl)propane (2), 1,4-bis(triethoxysilyl)butane (3), and Z-1,4-bis(triethoxysilyl)but-2-ene (10) undergo an intramolecular condensation reaction to give the six- and seven-membered cyclic disilsesquioxanes 6, 7, and 11. Subsequently, these cyclic monomers slowly react to form the tricyclic dimers 8, 9, and 12. With NaOH as polymerization catalyst, these cyclic silsesquioxanes readily reacted to afford gels that were shown by CP MAS 29Si NMR and infrared spectroscopies to retain some cyclic structures. Comparison of the porosity and microstructure of xerogels prepared from the cyclic monomers 6 and 7 with those of gels prepared directly from their acyclic precursors 2 and 3 indicates that the final pore structure of the xerogels is markedly dependent on the nature of the precursor. In addition, despite the fact that the monomeric cyclic disilsesquioxane species cannot be isolated from 1-3 under basic conditions due to their rapid rate of gelation, spectroscopic techniques also detected the presence of the cyclic structures in the resulting polymeric gels.
SILICIUMORGANISCHE VERBINDUNGEN LXXXVIII. DISILATRANYLALKANE
Birkofer, Leonhard,Grafen, Klaus
, p. 143 - 148 (1986)
By hydrosilation of triethoxyvinylsilane (1), 1,5-hexadiene (10) and 3,3-dimethyl-3-sila-1,4-pentadiene (14) with triethoxysilane (2) we obtained 1,2-bis(triethoxysilyl)ethane (3), 1,6-bis(triethoxysilyl)hexane (11) and 1,5-bis(triethoxysilyl)-3,3-dimethyl-3-silapentane (15).The reaction of 3 with triethanolamine (4), triisopropanolamine (6) and tris(1-t-butyl-ethanol)amine (8) leads to the 1,2-disilatranylethanes 5, 7 and 9.The 1,6-disilatranylhexanes 12 and 13 are formed from 11, 4 and 6 respectively, and 15 with 4 gives 3,3-dimethyl-1,5-disilatranyl-3-silapentane (16).
AN ACTIVE AND STABLE HYDROSILYLATION CATALYST: A SILICA SUPPORTED POLY-γ-MERCAPTOPROPYLSILOXANE-PLATINUM COMPLEX
Wang, Lin-Zhi,Jiang, Ying-Yan
, p. 39 - 44 (1983)
A silica-supported poly-γ-mercaptopropylsiloxane-platinum complex was prepared and used as hydrosilylation catalyst with 1-hexene and acetylene.When it was used as the catalyst for addition of triethoxysilane to 1-hexene at 80 deg C or room temperature, the product was n-hexyltriethoxysilane only, and the catalyst could be reused over twenty times (turnover numbers achieved were about 10.000) without any appreciable loss in the catalytic activity.The addition of triethoxysilane to acetylene by this catalyst at 80 deg C or room temperature under an atmospheric pressure gave vinyltriethoxysilane and bis(triethoxysilyl)ethane in good yields.
Efficient magnetically separable heterogeneous platinum catalyst bearing imidazolyl schiff base ligands for hydrosilylation
Huo, Yingpeng,Hu, Jiwen,Tu, Yuanyuan,Huang, Zhenzhu,Lin, Shudong,Luo, Xiaojiong,Feng, Chao
, (2021/02/06)
Reported herein is a magnetically separable heterogeneous nano catalyst Fe3O4@SiO2-biIMI- PtCl2, which is prepared by firstly applying a SiO2 coating onto readily synthesized magnetite nanoparticles via the hydrolysis condensation of tetraethyl orthosilicate (TEOS) under basic conditions, then modifying it using aminopropyl triethoxysilane and bis(imidazole) aldehyde, and finally incorporating a PtCl2 complex via coordination chemistry. The chemical structure and morphology of the nanocatalyst as well as the valence state and content of platinum within this catalyst were carefully characterized. This catalyst can mediate the hydrosilylation between 1-octene and hydrosilane, with the conversion of 1-octene reaching up to 99%, and it shows good regioselectivity as only β-adducts are identified. In addition, this catalyst can be reused for at least 5 cycles. The hydrosilylation reaction between different olefins and hydrosilanes can also be efficiently mediated by Fe3O4@SiO2-biIMI-PtCl2.
Platinum-Imidazolyl Schiff Base Complexes Immobilized in Periodic Mesoporous Organosilica Frameworks as Catalysts for Hydrosilylation
Huo, Yingpeng,Hu, Jiwen,Tu, Yuanyuan,Huang, Zhenzhu,Lin, Shudong,Hu, Yangfei,Feng, Chao
, (2020/05/18)
An imidazolyl Schiff base-containing periodic mesoporous organosilica (PMO) was synthesized via co-condensation reactions between a newly prepared bis (imidazolyl)imine-bridged bis silane and tetraethyl orthosilicate in the presence of cetyltrimethyl ammonium bromide as a soft template. The resultant as-synthesized PMO was then employed as a solid support for platinum catalysts. This complex was fully characterized via various techniques including FTIR, solid-state13C NMR, and 29Si-NMR spectroscopy, as well as N2 adsorption/desorption analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods. In addition, the catalyst was proven to efficiently mediate hydrosilylation reactions between olefins and hydrosilanes, and it can be reused for at least five cycles without significant loss of activity.
High Production of Hydrogen on Demand from Silanes Catalyzed by Iridium Complexes as a Versatile Hydrogen Storage System
Ventura-Espinosa, David,Sabater, Sara,Carretero-Cerdán, Alba,Baya, Miguel,Mata, Jose A.
, p. 2558 - 2566 (2018/03/13)
The catalytic dehydrogenative coupling of silanes and alcohols represents a convenient process to produce hydrogen on demand. The catalyst, an iridium complex of the formula [IrCp?(Cl)2(NHC)] containing an N-heterocyclic carbene (NHC) ligand functionalized with a pyrene tag, catalyzes efficiently the reaction at room temperature producing H2 quantitatively within a few minutes. As a result, the dehydrogenative coupling of 1,4-disilabutane and methanol enables an effective hydrogen storage capacity of 4.3 wt % that is as high as the hydrogen contained in the dehydrogenation of formic acid, positioning the silane/alcohol pair as a potential liquid organic hydrogen carrier for energy storage. In addition, the heterogenization of the iridium complex on graphene presents a recyclable catalyst that retains its activity for at least 10 additional runs. The homogeneous distribution of catalytic active sites on the basal plane of graphene prevents diffusion problems, and the reaction kinetics are maintained after immobilization.
