金属有机层(MOL)代表了新兴的一类可调谐和可功能化的二维材料。在这项工作中,由[Hf 6 O 4(OH)4(HCO 2)6组成的自支撑MOL的可扩展溶剂热合成报道了二级建筑单元(SBU)和苯-1,3,5-三苯甲酸酯(BTB)桥联配体。MOL结构直接通过TEM和AFM成像,并在与4'-(4-苯甲酸酯)-(2,2',2''-三吡啶)-5,5''-二羧酸盐(TPY)掺杂后铁中心为终端烯烃的氢化硅烷化提供高活性和可重复使用的单中心固体催化剂。基于MOL的非均相催化剂不受所有已知的多孔固体催化剂(包括金属有机骨架)的扩散限制。这项工作揭示了设计单中心固体催化剂的全新策略,并为一类具有分子功能的新型二维配位材料打开了大门。
Cobalt-Catalyzed Regiodivergent Hydrosilylation of Vinylarenes and Aliphatic Alkenes: Ligand- and Silane-Dependent Regioselectivities
作者:Chao Wang、Wei Jie Teo、Shaozhong Ge
DOI:10.1021/acscatal.6b02518
日期:2017.1.6
hydrosilylation of alkenes catalyzed by catalysts generated in situ from bench-stable Co(acac)2 and phosphine- or nitrogen-based ligands. A wide range of vinylarenes and aliphatic alkenes reacted to afford either branched (45 examples) or linear (37 examples) organosilanes in high isolated yields (average: 84%) and high regioselectivities (from 91:9 to >99:1). This transformation tolerates a variety of functional
NiCl2·6H2O/tBuOK, for the electrophilically activated hydrosilylation of terminal alkenes with primary silanes. This protocol provides excellent performance under mild reaction conditions: exclusive anti-Markovnikov selectivity, broad functional group tolerance (36 examples), and good scalability (TON = 5500). However, the secondary and tertiarysilanes are not suitable. Mechanistic studies revealed that
我们报告了一种简单有效的镍基催化体系NiCl 2 ·6H 2 O / t BuOK,用于末端烯烃与伯硅烷的亲电子活化氢化硅烷化。该方案在温和的反应条件下具有出色的性能:独特的抗马尔科夫尼科夫选择性,宽泛的官能团耐受性(36个示例)和良好的可扩展性(TON = 5500)。但是,仲和叔硅烷是不合适的。机理研究表明,这种均相催化的硅氢加成反应包括一种亲电子活化的Si-H键过程,而不会产生氢化镍。
set of base metal catalysts has been developed for regiodivergent alkene hydrosilylations: iron complexes of phosphine‐iminopyridine are selective for anti‐Markovnikov hydrosilylations (linear/branched up to >99:1), while the cobalt complexes bearing the same type of ligands provide an unprecedented high level of Markovnikov selectivity (branched/linear up to >99:1). Both systems exhibit high efficiency
Rapid, Regioconvergent, Solvent-Free Alkene Hydrosilylation with a Cobalt Catalyst
作者:Chi Chen、Maxwell B. Hecht、Aydin Kavara、William W. Brennessel、Brandon Q. Mercado、Daniel J. Weix、Patrick L. Holland
DOI:10.1021/jacs.5b08611
日期:2015.10.21
Alkene hydrosilylation is typically performed with Pt catalysts, but inexpensive base-metal catalysts would be preferred. We report a Co catalyst for anti-Markovnikov alkene hydrosilylation that can be used without added solvent at low temperatures with low loadings, and can be generated in situ from an air-stable precursor that is simple to synthesize from low-cost, commercially available materials
烯烃氢化硅烷化通常用 Pt 催化剂进行,但廉价的贱金属催化剂将是优选的。我们报告了一种用于抗马尔科夫尼科夫烯烃氢化硅烷化的 Co 催化剂,该催化剂可以在低温下以低负载量使用而无需添加溶剂,并且可以由空气稳定的前体原位生成,该前体易于从低成本的市售材料合成. 此外,Co 催化剂的混合物进行串联催化烯烃异构化/氢化硅烷化反应,将多种己烯异构体转化为相同的终端产物。这种区域会聚反应使用异构化作为好处而不是障碍。
Solution Synthesis of <i>N</i>
,<i>N</i>
-Dimethylformamide-Stabilized Iron-Oxide Nanoparticles as an Efficient and Recyclable Catalyst for Alkene Hydrosilylation
Highly activated, monodispersed N,N‐dimethylformamide (DMF)‐stabilized iron‐oxide nanoparticles (Fe2O3 NPs) were synthesized by using iron(III) acetylacetonate as a precursor under open‐air conditions. The resulting Fe2O3 NPs were characterized by various techniques (e.g., transmission electron microscopy, dynamic light scattering, X‐ray diffraction, X‐ray photoelectron spectroscopy, FTIR spectroscopy
使用乙酰丙酮铁(III)作为前体,在露天条件下合成了高度活化的,单分散的N,N-二甲基甲酰胺(DMF)稳定化的氧化铁纳米颗粒(Fe 2 O 3 NPs)。生成的Fe 2 O 3 NPs通过多种技术进行了表征(例如,透射电子显微镜,动态光散射,X射线衍射,X射线光电子能谱,FTIR光谱和X射线吸附近边缘结构)。铁2 O 3NP对烯烃的氢化硅烷化表现出有效的催化活性,而无需其他添加剂。通过用己烷/ DMF系统萃取,开发了有效的胶体催化剂的再循环方法,并且在五个循环中催化剂的再循环没有导致催化活性的任何显着损失。