air-stable palladium(II)-Schiff base complex supported on h-BN was simply prepared by using commercially available reagents. This nanomaterial was applied as an excellent and recyclable heterogeneous catalyst for the Suzuki and Heck cross-couplingreactions. And it has been characterized by FT-IR, XRD, SEM, XPS, TG and ICP-AES techniques. High yields, ligand-free, low reaction time, water as solvent
An environmentally friendly palladium(II) catalyst supported on cyclodextrin‐modified h‐BN was successfully prepared. The catalyst was characterized by FT‐IR, SEM, TG, XRD and XPS, and the loading level of Pd in h‐BN@β‐CD@Pd(II) was measured to be 0.088 mmol g−1 by ICP. It exhibits excellent catalytic activity for the Suzuki and Heck reactions in water, and can be easily separated and consecutively
已成功制备了负载在环糊精修饰的h-BN上的环保钯(II)催化剂。通过FT-IR,SEM,TG,XRD和XPS对催化剂进行了表征,ICP测得h-BN @β-CD@ Pd(II)中Pd的负载量为0.088 mmol g -1。它对水中的Suzuki和Heck反应具有出色的催化活性,并且可以轻松分离并连续重复使用至少9次。此外,使用该催化剂成功合成了一系列药理学有趣的产品,以证明其在制药工业中的潜在应用。最重要的是,这项工作为使用环糊精官能化的h-BN作为亲水性非均相催化剂的有效载体开辟了一条有趣的诱人途径。
Ligand-Free C-C Coupling Reactions Promoted by Hexagonal Boron Nitride-Supported Palladium(II) Catalyst in Water
exhibited excellent catalytic activities in the Suzuki and Heck reactions. Moreover, the catalyst could be easily recovered by simple filtration and reused at least ten times without significant loss of its catalytic activity. In general, this work demonstrates the possibility of using Schiff‐base@hexagonal boronnitride as an efficient support for heterogeneous catalysts.
Transition-Metal-Free C–C, C–O, and C–N Cross-Couplings Enabled by Light
作者:Wenbo Liu、Jianbin Li、Pierre Querard、Chao-Jun Li
DOI:10.1021/jacs.9b02684
日期:2019.4.24
and nitriles without the assistance of metal catalysts empowered by photoenergy. Control experiments reveal that among all common aryl electrophiles only aryl triflates are competent in these couplings whereas aryl iodides and bromides cannot serve as the coupling partners. DFT calculation reveals that once converted to the aryl radical cation, aryl triflate would be more favorable to ipso substitution
用于构建 CC、CO 和 CN 键的过渡金属催化交叉偶联已经彻底改变了化学科学。尽管取得了巨大的成就,但这些金属催化剂也存在一些问题,包括成本高、需要专门的配体、对空气和水分的敏感性以及所谓的“过渡金属残留问题”。不依赖于成熟的氧化加成、金属转移和还原消除机制范式的互补策略可能会消除所有这些与金属相关的问题。在此,我们表明芳基三氟甲磺酸酯可以与芳基三氟硼酸钾、脂肪醇和腈偶联,而无需借助光能赋能的金属催化剂。对照实验表明,在所有常见的芳基亲电试剂中,只有芳基三氟甲磺酸酯能够进行这些偶联,而芳基碘化物和溴化物不能作为偶联伙伴。DFT 计算表明,一旦转化为芳基自由基阳离子,芳基三氟甲磺酸酯将更有利于 ipso 取代。荧光光谱和循环伏安法研究表明,激发态丙酮和芳基三氟甲磺酸酯之间的相互作用对于这些偶联是必不可少的。预计本报告中的结果将为执行交叉耦合提供新的机会。荧光光谱和循环伏安法研究表明,激发态
Spatial Anion Control on Palladium for Mild C–H Arylation of Arenes
作者:Jyoti Dhankhar、Elisa González-Fernández、Chao-Chen Dong、Tufan K. Mukhopadhyay、Anthony Linden、Ilija Čorić
DOI:10.1021/jacs.0c09611
日期:2020.11.11
C-H arylation of arenes without the use of directing groups is a challenge, even for simple molecules, such as benzene. We describe spatial anion control as a concept for the design of catalytic sites for C-H bond activation, thereby enabling nondirected C-H arylation of arenes at ambient temperature. The mild conditions enable late-stage structural diversification of biologically relevant small molecules