摘要具有三种Si-OH基团的三种 不完全缩合的多面体低聚倍半硅氧烷(T 7 -POSS):(iC 4 H 9)7 Si 7 O 9(OH)3,(iC 8 H 17)7 Si 7 O 9( OH)3和(C 6 H 5)7 Si 7 O 9(OH)3通过通用的三步法(水解,缩合和中和)从iC 4 H 9制备以LiOH·H 2 O为催化剂,分别为Si(OEt)3,iC 8 H 17 Si(OEt)3和C 6 H 5 Si(OEt)3。通过FTIR,1 H NMR,13 C NMR,29 Si NMR,MALDI-TOF MS和XRD表征了三个T 7 -POSS的结构。三个T 7 -POSS的精确不完全笼状结构表明,建立的三步法是一种高产合成T 7 -POSS的通用而有效的方法。合成异丁基-T 7,异辛基-T的最佳反应条件7和苯基-T 7 POSS已经提出,涉及丙酮和助溶剂时,RSI(OET)的摩尔比3:将LiOH·H
A cyclopentadienyl–silsesquioxane titanium complex efficiently catalyses the selective oxidation of sulfides to sulfoxides (85–98% yield in 5 min at ambient temperature) and sulfones with near-stochiometric amount of aqueous H2O2 in methanol.
Synthesis and Hydrosilylation of Vinyl-Substituted Open-Cage Silsesquioxanes with Phenylsilanes: Regioselective Synthesis of Trifunctional Silsesquioxanes
with vinyldiorganosilyl functional groups, which allows further modification. Detailed studies of hydrosilylation of sterically different open-cage vinylsilsesquioxanes with a wide spectrum of phenylsilanes catalyzed by platinum and rhodium compounds are also reported. The influence of the reaction parameters, types of reagents, and catalysts employed on the efficiency of the process was examined.
Kinetic and Binding Studies Reveal Cooperativity and Off‐Cycle Competition for H‐Bonding Catalysis with Silsesquioxane Silanols
作者:Jake R. Jagannathan、Kayla M. Diemoz、Karina Targos、James C. Fettinger、Annaliese K. Franz
DOI:10.1002/chem.201903693
日期:2019.11.22
using a 31 P NMR probe. Evaluation of a Friedel-Crafts addition reaction shows that phenyl-POSS-triol is active as an H-bond donor catalyst whereas other POSS silanols studied are not. An in-depth kineticstudy (using RPKA and VTNA) highlights the concentration-dependent H-bonding behavior of POSS-triols, which is attributed to intermolecular association forming an off-cycle dimeric species. Binding constants
报道了不完全缩合的多面体低聚倍半硅氧烷(POSS)硅烷醇的催化活性,动力学和氢键能力的定量化。POSS-三醇是邻域二氧化硅表面位点的均质模型,与使用31 P NMR探针定量的其他硅烷醇和醇相比,其H键键增强。对Friedel-Crafts加成反应的评估表明,苯基-POSS-三醇作为氢键供体催化剂具有活性,而所研究的其他POSS硅烷醇则没有。深入的动力学研究(使用RPKA和VTNA)强调了POSS-三醇的浓度依赖性H键行为,这归因于分子间缔合形成了一个循环外的二聚体。结合常数为在较高浓度下降低的H键能力提供了额外的支持,这归因于竞争性联系。
Influence of polyhedral oligomeric silsesquioxanes (POSS) on the luminescence properties of non-conjugated copolymers based on iridium complex and carbazole units
luminescence lifetimes of the copolymers were 0.28–1.60 μs, indicating phosphorescence emission. The luminescence properties of the copolymers were improvedsignificantly by incorporating bulky POSS into the polymer side-chain, and the maximum quantum efficiency was found to be 52.4% for ternary copolymer PCz-Ir1.0-POSS6, which was more than six times than that of binary copolymer PCz-Ir1.0 (Φpl = 7.7%).
derivatives as multifunctional reagents. This study concerns the incompletely condensed silsesquioxanes and germasilsesquioxanes with vinyl-substituted silyl and germyl functional groups, which allow further modification. Furthermore, our experiments have been extended to the synthesis of a new subclass of completely condensed vinylgermasilsesquioxanes. These hybrid buildingblocks were obtained selectively