College of Chemistry, Xiangtan University, Hunan 411105, China; Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, China.
College of Chemistry, Xiangtan University, Hunan 411105, China.
J Colloid Interface Sci. 2016 Feb 1;463:13-21. doi: 10.1016/j.jcis.2015.10.035. Epub 2015 Oct 23.
To improve the catalytic activity and reduce the dosage of noble metal catalysts has attracted much more attention for organic synthetic chemists. We facilely fabricated multilayer films of PEI-(PdCl2/1)n through layer-by-layer (LBL) self-assembly method (PEI=polyethylenmine, 1=2,2',7,7'-tetra(4-pyridyl)-9,9'-spirobifluorene, psf). UV-vis spectroscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to monitor the growth of multilayer films. X-ray photoelectron spectroscopy (XPS) proved the palladium and ligand 1 were deposited on the film. The PEI-(PdCl2/1)n multilayer films were used as the cisterns of catalysts to gradually discharge high active catalytic moieties in the Suzuki-Miyaura, Heck and Sonogashira cross-coupling reactions. The Pd-loading was as low as 12.1×10(-6)mol% measured by inductively coupled plasma OES spectrometer (ICP), and gave high yields in the typical reactions of bromobenzenes with phenylboronic acids. The LbL catalyst featured the simplicity of fabrication, high efficiency, reusability, convenient control and no sensitive to air in the reactions.
为了提高催化活性并减少贵金属催化剂的用量，有机合成化学家越来越关注这一问题。我们通过层层自组装（LBL）方法（PEI=聚乙烯亚胺，1=2,2',7,7'-四（4-吡啶基）-9,9'-螺二芴，psf）简便地制备了 PEI-(PdCl2/1)n 多层膜。紫外可见光谱、原子力显微镜（AFM）和扫描电子显微镜（SEM）用于监测多层膜的生长。X 射线光电子能谱（XPS）证明钯和配体 1 沉积在薄膜上。PEI-(PdCl2/1)n 多层膜可用作催化剂的储库，以逐步在 Suzuki-Miyaura、Heck 和 Sonogashira 偶联反应中释放高活性催化部分。通过电感耦合等离子体发射光谱仪（ICP）测量，Pd 的负载量低至 12.1×10(-6)mol%，在溴苯与苯硼酸的典型反应中收率很高。LbL 催化剂具有制备简单、效率高、可重复使用、方便控制和反应过程中对空气不敏感等特点。
