Karimi Masoud, Ramazani Ali, Sajjadifar Sami, Rezayati Sobhan
Department of Chemistry, Faculty of Science, University of Zanjan Zanjan 45371-38791 Iran
Department of Biotechnology, Research Institute of Modern Biological Techniques (RIMBT), University of Zanjan Zanjan 45371-38791 Iran.
RSC Adv. 2023 Oct 4;13(42):29121-29140. doi: 10.1039/d3ra05649j.
In the present study, a copper(ii) complex containing a pyridine-2-carbaldehyde ligand and its direct binding onto ethylenediamine functionalized with FeO@SiO nanoparticles [Cu(ii)-Schiff base-(CH)-SiO@FeO] as a heterogeneous magnetic nanocatalyst can be easily prepared using a multi-step method. Next, the structural and magnetic properties of the synthesized nanoparticles were identified using Fourier-transform infrared spectroscopy (FT-IR), inductively coupled plasma (ICP), vibrating-sample magnetometry (VSM), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), PXRD (Powder X-ray diffraction), Brunauer-Emmett-Teller (BET), and energy-dispersive X-ray spectrometry (EDX) techniques. TEM images reveal that the average particle size distribution was found to be in the range of 45-55 nm with spherical shape. The PXRD analysis indicated that the crystallite size was found to be 35.2 nm. The synthesized nanocatalyst exhibited a very good catalytic ability in the synthesis reaction of pyran derivatives and 2-benzylidenemalononitrile derivatives. Product 2-amino-7,7-dimethyl-4-(4-nitrophenyl)-5-oxo-5,6,7,8-tetrahydrobenzo[]pyran 4e was achieved in 97% yield with a TON of 129.3 and a TOF of 646.6 h and product 2-(4-cyanobenzylidene)malononitrile 3j was achieved in 96% yield with a TON of 128 and a TOF of 984.6 h. In addition, the synthesized nanocatalyst was easily separated from the reaction mixture by a magnet and used 7 consecutive times without significant loss of catalytic activity. Also, leaching of copper metal from the synthesized nanocatalyst was very insignificant for this reaction.
在本研究中，使用多步方法可以轻松制备一种含有吡啶 - 2 - 甲醛配体的铜（II）配合物，以及它作为非均相磁性纳米催化剂直接结合到用FeO@SiO纳米颗粒功能化的乙二胺上[Cu（II）-席夫碱 - （CH）-SiO@FeO]。接下来，使用傅里叶变换红外光谱（FT - IR）、电感耦合等离子体（ICP）、振动样品磁强计（VSM）、透射电子显微镜（TEM）、场发射扫描电子显微镜（FE - SEM）、热重分析（TGA）、粉末X射线衍射（PXRD）、布鲁诺尔 - 埃米特 - 泰勒（BET）和能量色散X射线光谱（EDX）技术来鉴定合成纳米颗粒的结构和磁性。TEM图像显示平均粒径分布在45 - 55 nm范围内，呈球形。PXRD分析表明微晶尺寸为35.2 nm。合成的纳米催化剂在吡喃衍生物和2 - 苄叉基丙二腈衍生物的合成反应中表现出非常好的催化能力。产物2 - 氨基 - 7,7 - 二甲基 - 4 - （4 - 硝基苯基） - 5 - 氧代 - 5,6,7,8 - 四氢苯并[]吡喃4e的产率为97%，TON为129.3，TOF为646.6 h，产物2 - （4 - 氰基亚苄基）丙二腈3j的产率为96%，TON为128，TOF为984.6 h。此外，合成的纳米催化剂可以通过磁铁轻松地从反应混合物中分离出来，并连续使用7次，催化活性没有明显损失。而且，在该反应中，合成纳米催化剂中铜金属的浸出非常不明显。
