吸电子基团对席夫碱及其钯配合物在抑菌及催化活性方面的影响

报道了2,6-二异丙基苯胺缩苯甲醛或2,4-二氯苯甲醛席夫碱(L1和L2)及其钯配合物(1和2)的合成,并通过元素分析、红外光谱、X-射线单晶衍射等方法对席夫碱配体及配合物进行了表征。通过与已报道的席夫碱L1及其钯配合物1结构相比较,发现引入吸电子取代基合成的一个新的席夫碱及其钯配合物(L2和2)对抑菌及催化活性有较大影响。抑菌活性试验表明,配体及配合物均具有良好的抑菌活性,配合物相对于配体具有更好的抑菌效果,配体苯环上的吸电子取代基能有效提高抑菌活性。研究了两组配合物(1和2)对溴代苯和丙烯酸Heck交叉偶联生成苯丙烯酸的催化性能,考察了不同反应因素(缚酸剂种类、反应温度及溶剂)对该反应的影响,确定了反应的最佳条件;催化实验结果显示吸电子基团的引入增加了钯配合物的空间位阻效应进而降低其催化活性。

Effect of Electron-Withdrawing Groups of Schiff Base and Its Palladium Complex on Antimicrobial and Catalytic Activities

Two Schiff Bases (L1 and L2) and their palladium complexes (1 and 2) were prepared by the condensation of 2,6-diisopropylaniline with benzaldehyde and 2,4-dichlorobenzaldehyde, respectively, and characterized by elemental analysis, IR-spectroscopy and single crystal X-ray diffraction. Compared with known structures of Schiff base (L1) and its palladium complex (1), we discovered that the introduction of electro-withdrawing groups of L2 and complex 2 have effects on antimicrobial and catalytic activities. The antimicrobial activities results indicated that the ligands and their complexes perform good activities, and the complexes have better effect than the ligands, and the electro-withdrawing groups will effectively improve the activities. The Heck reactions of bromobenzene with acrylic acid catalyzed by complex 1 and 2 have also been studied. We have investigated the effect of different factors (bases, temperature and solvent) on reaction and finally determined the optimum reaction condition. The catalytic activities results shown that the electro-withdrawing groups of ligands will increase the steric effect of 1 and 2, and reducing their activities. CCDC: 882286,L1; 882287, 2; 222403, 1; 882289, 2.