Department of Chemistry, College of Sciences and Arts - Alkamil, University of Jeddah, Jeddah 23218, Saudi Arabia.
Chemistry Department, College of Science and Arts-Sharurah, Najran University, Sharurah, Saudi Arabia; Department of Chemistry, Faculty of Science, Suez Canal University, Ismailia, Egypt.
Int J Biol Macromol. 2021 Aug 1;184:454-462. doi: 10.1016/j.ijbiomac.2021.06.105. Epub 2021 Jun 19.
Taking the advantage of multifunctional characteristics of chitosan (CS), we have developed new scaffolds (imidazolium-vanillyl-chitosan Schiff bases (IVCSSBs)) for supporting Pd(II) and Ru(II) ions in catalyzing Suzuki coupling reactions. The structures of new materials were described based on their elemental, spectral, thermal, and microscopic analysis. The strong interactions between the binding sites of IVCSSB ligand (OH, H-C=N, and OCH groups) and Pd(II) ions resulted in the formation of an excellent heterogeneous catalyst (Pd(II)IVCSSB1) with amazing catalytic activity (up to 99%) and highly stable in the reaction medium. The reusability experiments for Pd(II)IVCSSB revealed that there is no appreciable decrease in its catalytic activity even after five consecutive operation runs. Furthermore, this heterogeneous catalyst showed an excellent selectivity toward the cross-coupling reaction where no homo-coupling byproducts were observed in the H NMR spectra of the obtained products. Consequently, the present ionic catalytic system may open a new window for a novel generation of ionic bio-based catalysts for organic transformations.
利用壳聚糖（CS）的多功能特性，我们开发了新的支架（咪唑啉-香草基壳聚糖席夫碱（IVCSSBs）），用于在催化 Suzuki 偶联反应中支撑 Pd(II)和 Ru(II)离子。根据它们的元素、光谱、热和微观分析，描述了新材料的结构。IVCSSB 配体（OH、H-C=N 和 OCH 基团）的结合位点与 Pd(II)离子之间的强相互作用导致形成了具有惊人催化活性（高达 99%）和在反应介质中高度稳定的优异非均相催化剂（Pd(II)IVCSSB1）。Pd(II)IVCSSB 的重复使用实验表明，即使经过五次连续操作，其催化活性也没有明显下降。此外，这种非均相催化剂对交叉偶联反应表现出优异的选择性，在获得的产物的 H NMR 谱中没有观察到同偶联副产物。因此，本离子催化体系可能为有机转化的新一代离子生物基催化剂开辟了新的窗口。
