...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Catalysis science & technology >Palladium catalytic systems with hybrid pyrazole ligands in C-C coupling reactions. Nanoparticles versus molecular complexes
【24h】

Palladium catalytic systems with hybrid pyrazole ligands in C-C coupling reactions. Nanoparticles versus molecular complexes

机译：C-C偶联反应中的杂化吡唑配体钯催化系统。 纳米颗粒与分子复合物

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

This paper reports the comparison of the chemoselectivity of two different Pd catalytic systems, namely molecular and colloidal systems, in C-C coupling reactions. For this purpose, new hybrid pyrazole derived ligands containing alkylether, alkylthioether or alkylamino moieties have been synthesized and used to form Pd(II) complexes and to stabilize Pd nanoparticles (Pd NPs). With the aim of studying the coordination mode of the ligands and further to understand their role in catalysis, both types of Pd species were characterized by appropriate techniques. In C-C coupling reactions promoted by different Pd colloidal systems, several reports evidenced that active species are molecular catalysts leached from Pd NPs. The most important feature of this work relies on the differences observed in the output of C-C coupling reactions, depending on the colloidal or molecular nature of the catalyst employed. Thus, molecular systems carry out typical Suzuki-Miyaura cross-coupling, together with the dehalogenation of the substrate in different proportions. In contrast, Pd NPs catalyze either Suzuki-Miyaura or C-C homocoupling reactions depending on the haloderivative used. Interestingly, Pd NPs catalyze the quantitative dehalogenation of 4-iodotoluene. Differences observed in the chemoselectivity of these two catalytic systems support that reactions carried out with Pd NPs stabilized with the hybrid pyrazole ligands employed here take place on the surface of the colloids.
机译：本文报告了在C-C偶联反应中的两个不同PD催化系统（即分子和胶体系统）的化学选择性比较。为此，已合成了含有烷基醚，烷基硫乙醚或烷基氨基部分的新杂化吡唑配体，并用于形成PD（II）配合物并稳定PD纳米颗粒（PD NPS）。为了研究配体的协调模式并进一步了解它们在催化中的作用，两种类型的PD物种均以适当的技术为特征。在由不同的PD胶体系统促进的C-C偶联反应中，一些报道证明了活性物种是从PD NP中浸出的分子催化剂。这项工作的最重要特征取决于C-C偶联反应的输出中观察到的差异，这取决于所用催化剂的胶体或分子性质。因此，分子系统进行了典型的铃木 - 米约拉拉交叉偶联，并以不同比例的底物进行脱卤。相比之下，PD NPS催化铃木 - 米龙或C-C的c-c偶联反应，具体取决于所使用的haloderivive。有趣的是，PD NPS催化了4-碘醇的定量脱卤。在这两个催化系统支持的化学选择性中观察到的差异，该反应与此处采用的杂化吡唑配体稳定的PD NPS发生在胶体表面上。

著录项

相似文献

  • 外文文献
  • 中文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号