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Novel ordered cyclopalladated aryl imine monolayers—Structure Designing for Enhancing Catalytic Performance
Molecular Catalysis ( IF 3.9 ) Pub Date : 2019-11-25 00:00:00 , DOI: 10.1016/j.mcat.2019.110671
Erran Song , Jiong Wang , Tiesheng Li , Wuduo Zhao , Minghua Liu , Yangjie Wu

Two new Schiff-based cyclopalladated aryl imine catalysts (denoted as Fc-Pd and B-Pd) were prepared and their ordered self-assembled molecular monolayers (called as Si@F-Pd and Si@B-Pd) were fabricated. Their catalytic performances were evaluated using Suzuki coupling reaction as a templet with water as solvent, in which the structure on their catalytic properties and mechanism were systematic studied. Si@F-Pd and Si@B-Pd exhibited higher catalytic active with higher turnover number (TON) (149095 and 173214) and could be recycled at least 8 time and 6 time, respectively. The molecular structure and geometry of the catalyst was an important factor for their catalytic performance and stability, in which that large steric and structure made it easy to alter the electronic environment and structure, regulate the state of catalytic active surface which are contributed to their high catalytic activity. It was the fact that the electron rich of Pd may be formed by transferring electrons from ligand to Pd which became more nucleophilic for enhancing the facile oxidative addition with aryl halides. The catalytic mechanism proceeded a quasi-homogenous property on the surface in the form of leaching and re-deposition manner. Si@Fc-Pd acted as catalytic sites (surface) and sources or likely a reservoir for active species leaching, which formed a cycling state of equilibrium. It was clarified that the homogeneous and heterogeneous catalysis occurred at the same period on the surface and in solution, which was confirmed by hot-filtration, poison text, three-phase text, AFM, CV, XPS and ReactIR.



中文翻译:

新型有序环palpalated芳基亚胺单层—结构设计,以提高催化性能

两种新的基于席夫(Schiff)的环palpalated芳基亚胺催化剂(表示为Fc-PdB-Pd制备),并制造它们的有序自组装分子单层(称为Si @ F-Pd和Si @ B-Pd)。以铃木偶联反应为模板剂,以水为溶剂,对其催化性能进行了评价,对催化性能的结构和机理进行了系统的研究。Si @ F-Pd和Si @ B-Pd表现出更高的催化活性和更高的周转数(TON)(149095和173214),可以分别回收至少8次和6次。催化剂的分子结构和几何形状是影响其催化性能和稳定性的重要因素,其中大的空间和结构使其易于改变电子环境和结构,调节催化活性表面的状态,这有助于它们的高催化性能。催化活性。事实是,富电子的Pd可能是通过将电子从配体转移到Pd上而形成的,Pd变得更具亲核性,从而增强了芳基卤化物的简便氧化加成。催化机理以浸出和再沉积的形式在表面上具有准均一的性质。Si @ Fc-Pd充当催化位点(表面)和来源,或者可能是活性物质浸出的储存库,从而形成了平衡的循环状态。澄清了均相和非均相催化同时发生在表面和溶液中,这通过热过滤,毒物文本,三相文本,AFM,CV,XPS和ReactIR证实。催化机理以浸出和再沉积的形式在表面上具有准均一的性质。Si @ Fc-Pd充当催化位点(表面)和来源,或者可能是活性物质浸出的储存库,从而形成了平衡的循环状态。澄清了均相和非均相催化同时发生在表面和溶液中,这通过热过滤,毒物文本,三相文本,AFM,CV,XPS和ReactIR证实。催化机理以浸出和再沉积的形式在表面上表现出准均一的性质。Si @ Fc-Pd充当催化位点(表面)和来源,或者可能是活性物质浸出的储存库,从而形成了平衡的循环状态。澄清了均相和非均相催化同时发生在表面和溶液中,这通过热过滤,毒物文本,三相文本,AFM,CV,XPS和ReactIR证实。

更新日期:2019-11-26
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