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Pd-bound functionalized mesoporous silica as active catalyst for Suzuki coupling reaction: Effect of OAcˉ, PPh3 and Clˉ ligands on catalytic activity
Journal of Solid State Chemistry ( IF 3.3 ) Pub Date : 2018-01-31 , DOI: 10.1016/j.jssc.2018.01.027
Trisha Das , Hiroshi Uyama , Mahasweta Nandi

Three new palladium catalysts, PdCat-I, PdCat-II and PdCat-III, immobilized over heterogeneous silica support have been synthesized using different ligands attached to the palladium precursor. The ligands that have been used in this study are acetate, triphenylphosphine and chloride in PdCat-I, PdCat-II and PdCat-III, respectively. The ligands have different effect on stability of the compounds and impart different oxidation states to the metal center. The materials have been characterized by powder X-ray diffraction, nitrogen adsorption-desorption studies, transmission electron microscopy, thermal analysis, and different spectroscopic techniques. The Pd-content of the samples have been determined by ICP-AES analysis. The materials have been used as catalysts for Suzuki coupling reaction of aryl halides with phenylboronic acid under mild conditions. A comparative study has been carried out to ascertain the effect of the nature of different ligands on the outcome of the catalytic reactions. Products have been identified and estimated by 1H NMR and gas chromatography. The results show that the best yields are obtained with the catalyst containing triphenylphosphine as the ligand in methanol. Such type of work to study the effect of ligand on Suzuki coupling reaction over functionalized mesoporous silica heterogeneous catalysts have not been carried out so far.



中文翻译:

钯键合官能化介孔二氧化硅作为铃木偶联反应的活性催化剂:OAcˉ,PPh 3Clˉ配体对催化活性的影响

固定在非均相二氧化硅载体上的三种新型钯催化剂,PdCat-IPdCat-IIPdCat-III,是使用与钯前体连接的不同配体合成的。在这项研究中使用的配体是PdCat-IPdCat-IIPdCat-III中的乙酸盐,三苯膦和氯化物分别。配体对化合物的稳定性具有不同的影响,并赋予金属中心不同的氧化态。通过粉末X射线衍射,氮吸附-脱附研究,透射电子显微镜,热分析和不同的光谱学技术对材料进行了表征。样品中的Pd含量已通过ICP-AES分析确定。该材料已用作温和条件下芳基卤化物与苯基硼酸的Suzuki偶联反应的催化剂。已经进行了比较研究以确定不同配体的性质对催化反应的结果的影响。产品已被1鉴定和估算1 H NMR和气相色谱。结果表明,在甲醇中,以三苯基膦为配体的催化剂可获得最佳收率。迄今为止,尚未进行这类研究配体对功能化介孔二氧化硅非均相催化剂上的Suzuki偶联反应的影响的工作。

更新日期:2018-02-23
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