Synthesis of organosiloxanes with reactive groups at silicon atoms
摘要:
The heterofunctional condensation of (dihydroxy)organodisiloxanes and -trisiloxanes with vinyl(hydro)organodichlorosilanes was studied with the purpose of preparing alpha,omega-dichloroorganosiloxanes with reactive Si-H and Si-CH=CH2 groups. During the isolation, 1,9-dichloro-1,9-dihydropentamethyloctasiloxane disproportionates with the elimination of (dichloro)methylsilane to form heptamethylcyclotetrasiloxane. A series of cyclotetra-, cyclohexa-, and cyclooctasiloxanes with Si-H and Si-CH=CH2 groups was obtained by the condensation of alpha,omega-dihydroxyorganosiloxanes with alpha,omega-(dichloro)divinyl(dihydro)organosiloxanes.
Wettability-Driven Palladium Catalysis for Enhanced Dehydrogenative Coupling of Organosilanes
作者:Jian-Dong Lin、Qing-Yuan Bi、Lei Tao、Tao Jiang、Yong-Mei Liu、He-Yong He、Yong Cao、Yang-Dong Wang
DOI:10.1021/acscatal.6b03233
日期:2017.3.3
for designing chemically and biologically useful organosilicon compounds. Heterogeneous catalytic systems sufficiently active, selective, and durable for dehydrosilylation reactions under mild conditions have been lacking to date. Herein, we report that the hydrophobic characteristics of the underlying supports can be advantageously utilized to enhance the efficiency of palladium nanoparticles (Pd NPs)
oxidation of organosilanes to silanols with H2O2 under neutral reaction conditions has been accomplished. A variety of organosilanes with alkyl, aryl, alknyl, and heterocyclic substituents were tolerated, as well as sterically hindered organosilanes. The oxidation appears to proceed by a concerted process involving a manganese hydroperoxide species. Featuring mild reaction conditions, fast oxidation,
在中性反应条件下,用H 2 O 2进行的第一次锰催化的有机硅烷氧化为硅烷醇。可以耐受具有烷基,芳基,炔基和杂环取代基的多种有机硅烷,以及受阻位有机硅烷。氧化似乎是通过涉及氢过氧化锰物质的协同过程进行的。该方案具有温和的反应条件,快速的氧化作用,并且没有废副产物,可实现硅烷醇和硅烷二醇的低成本,生态友好的合成。
Highly selective oxidation of organosilanes with a reusable nanoporous silver catalyst
Room temperature highlyselectiveoxidation of organosilanes to organosilanols and organosilyl ethers is achieved in liquid-phase with dealloyed nanoporous silver catalysts. In both cases, aromatic and aliphatic silanes can be effectively converted into the corresponding silanols and silyl ethers by using water and alcohols as oxidant, respectively. Moreover, hydrogen gas is the only by-product and
developed as a highly active, selective, and stable catalyst for the oxidation of silanes with water with a turnover frequency as high as 50 200 h−1, far exceeding most known catalysts based on total gold content. Other hydrosilanes bearing unsaturated functional groups also lead to corresponding silanols under mild reaction conditions without formation of any side products in good or excellent yields
锚固在mpg‐C 3 N 4(519 ppm Au负载)上的单中心Au是一种高活性,选择性和稳定的催化剂,可用于水氧化硅烷的周转频率高达50 200 h -1,以总金含量计,远远超过了大多数已知的催化剂。在温和的反应条件下,其他带有不饱和官能团的氢硅烷也可以生成相应的硅烷醇,而不会以高收率或优良收率形成任何副产物。球差校正电子显微镜和扩展的X射线吸收精细结构测量均证实了通过mpg-C 3 N 4稳定的Au原子的原子色散。催化活性Au I的配位由三氮杂三嗪重复单元中的三个氮或碳原子组成的碳原子不仅阻止了Au原子的聚集,而且使表面的Au I具有高活性,这与均质的Au I物种完全不同。