Four new symmetrical Schiff bases derived from 2,2’-diamino-4,4’-dimethyl-1,1’-biphenyl-salicylaldehyde have been synthesized and characterized by elemental analysis and different spectroscopic techniques. The reaction of 2,2’-diamino-4,4’-dimethyl-1,1’-biphenyl with two equivalents of 5-tert-butyl-, 3,5-dinitro-, 3,5-dibromo- and 3-tert-butyl-salicylaldehyde yielded 2,2’-bis(5-tert-butyl-salicylideneamino)-4,4’-dimethyl-1,1’-biphenyl (A1) as well as the 3,5-dinitro- (A2), 3,5-dibromo- (A3) and 3-tert-butyl- (A4) substituted derivatives. The tetradentate ligands were then reacted with copper-, manganese- and zinc-acetate producing the tetra-coordinate metal complexes which were characterized by FTIR, UV-Visible spectroscopy, magnetic susceptibility and elemental analysis. Zinc complexes were characterized by 1H-NMR spectroscopy. Density functional theory (DFT) calculations at the B3LYP/6-31G(d) level of theory were carried out to fully optimize and examine the molecular geometries of complexes. Subsequently, IR vibrational and UV-Vis absorption spectra were computed and correlated with the observed values and the results are in good agreement with the experimental data. The anticancerous and antiproliferative activity of the A3 ligand and its metal complexes were determined.

中文翻译：

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某些铜，锰和锌配合物与对称2,2'-二氨基-4,4'-二甲基-1,1'-联苯-水杨醛衍生的配体的合成，计算，抗癌和抗增殖作用

合成了四种新的由2,2'-二氨基-4,4'-二甲基-1,1'-联苯基-水杨醛衍生的对称席夫碱，并通过元素分析和不同的光谱技术对其进行了表征。2,2'-二氨基-4,4'-二甲基-1,1'-联苯与两个当量的5-叔丁基-，3,5-二硝基-，3,5-二溴-和3-的反应叔丁基水杨醛制得2,2'-双（5-叔丁基-水杨基亚氨基）-4,4'-二甲基-1,1'-联苯（A1）以及3,5-二硝基-（A2 ），3,5-二溴-（A3）和3-叔丁基-（A4）取代的衍生物。然后使四齿配体与乙酸铜，锰和锌锌反应，生成四配位金属配合物，通过FTIR，紫外可见光谱，磁化率和元素分析对其进行表征。锌配合物通过1 H-NMR光谱表征。进行了B3LYP / 6-31G（d）理论水平的密度泛函理论（DFT）计算，以充分优化和检查复合物的分子几何形状。随后，计算了IR振动和UV-Vis吸收光谱并将其与观测值相关，结果与实验数据非常吻合。测定了A3配体及其金属配合物的抗癌和抗增殖活性。