Careful investigation of the hydrosilylation of olefins at poly(ethylene glycol) chain ends and development of a new silyl hydride to avoid side reactions
作者:Hyunseo Shin、Bongjin Moon
DOI:10.1002/pola.28924
日期:2018.3.1
Hydrosilylation of olefin groups at poly(ethyleneglycol) chain ends catalyzed by Karstedt catalyst often results in undesired side reactions such as olefin isomerization, hydrogenation, and dehydrosilylation. Since unwanted polymers obtained by side reactions deteriorate the quality of end‐functional polymers, maximizing the hydrosilylation efficiency at polymer chain ends becomes crucial. After careful
Reactions of allyl-functionalized poly(ethylene glycol) (PEG) derivatives with alkoxysilanes proceeded efficiently to furnish the corresponding hydrosilylated products in good to excellent yields using a ruthenium catalyst, [RuCl2(nbd)]n. A preliminary mechanistic study supported the pivotal role of the PEG moiety, which coordinated to the ruthenium atom during the reaction to achieve high reaction
Enhanced Hydrolytic Stability of Siliceous Surfaces Modified with Pendant Dipodal Silanes
作者:Barry Arkles、Youlin Pan、Gerald L. Larson、Mani Singh
DOI:10.1002/chem.201402757
日期:2014.7.21
The stability of surfaces in aqueous environments prepared from dipodalsilanes with hydrophobic alkyl functionality is compared to the stability of similar surfaces prepared from the conventional silanes. In strongly acidic and brine environments, surfacesmodified with dipodalsilanes demonstrate markedly improved resistance to hydrolysis compared to surfaces prepared from conventional silanes. Pendant
双足硅烷具有两个可以共价键合到表面的硅原子。与通常用于表面改性的传统硅烷相比,它们在保持表面涂层、粘合剂底漆和复合材料在水性环境中的完整性方面具有明显的优势。引入了新的非功能性和功能性双足硅烷,其结构包含“侧链”而非“桥连”有机官能团。将由具有疏水性烷基官能团的双足硅烷制备的表面在水性环境中的稳定性与由常规硅烷制备的类似表面的稳定性进行比较。在强酸性和盐水环境中,与由传统硅烷制备的表面相比,用双足硅烷改性的表面显示出显着提高的耐水解性。悬垂双足硅烷比桥连双足硅烷表现出更高的稳定性。通过二硅氧烷键的水解形成硅烷醇物质的表观平衡常数被确定为K c =[SiOH] 2 /[Si-O-Si][H 2 O]=6±1×10 -5有助于理解双足硅烷改性表面的水解稳定性增强。
Novel perfluoroalkylated oligo(oxyethylene) methyl ethers with high hemocompatibility and excellent co-emulsifying properties for potential biomedical uses
non-hydroxylated spacer was synthesized from allyl methyl ethers of oligo(oxyethylene) glycols using radical additions of perfluoroalkyl iodides and subsequent selective reductions of the C–I bond in the adducts in overall yields of 23–69%. Some of the novel amphiphilic compounds displayed very low hemolytic activity to erythrocytes and excellent co-emulsifying properties on testing on perfluorodecalin/Pluronic F-68
water-soluble polysilanes take highly entangled form in water. Solvatochromic redshift is induced by THF in aqueous solution of water-soluble polysilanes. This solvatochromism is ascribed to disentanglement the non-polar main chain by non-polar solvent. Another type of solvatochromic shift is also caused by (CF3)2CHOH (HFIP) in non-polar solvent (benzene, CH2Cl2) or even in (CH3)2CHOH solution, where