Abstract Six new lanthanide complexes, [Ln(NO3)2(L1H2)](NO3).xCHCl3.yH2O {Ln = Yb (1), x = 1, y = 2; Nd (3), x = 2, y = 3 and Dy (5), x = 2, y = 2} and [Ln(NO3)2(L2H2)](NO3).xCHCl3 {Ln = Yb (2), x = 1; Nd (4), x = 2 and Dy (6), x = 2}, were prepared by NNNOO-donor pentadentate Schiff base ligands N,N′-bis(3-methoxysalicylidene)−2,2′-diaminoethylamine (L1H2) and N,N′-bis(2-hydroxynaphthalidene)−2,2′-diaminoethylamine (L2H2). These synthesized complexes were characterized by elemental analysis, FT-IR, 1H NMR, UV-vis spectroscopy, and mass spectrometry. The thermal characteristics of complexes were studied by TGA technique. The observation of the fluorescence emission properties of ligands L1H2 and L2H2 and its Ln(III) complexes in DMSO solution at excitation wavelength of 320 nm shows that the ligands favor energy transfers to the emitting energy level of Ln(III) complexes. The computational calculations using density functional theory of ligands and its Yb((III) complexes were performed to obtain optimized molecular geometry, the highest occupied molecular orbital, the lowest unoccupied molecular orbital and other parameters. The Schiff bases, metal salts, and its Ln(III) complexes were screened for their in vitro antibacterial studies against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Salmonella typhi bacterial strains. The results of the antibacterial investigation show that the lanthanide complexes possess more potent bactericide properties than ligands and metal salts. Graphical Abstract

中文翻译：

---

席夫碱配体衍生的单核 Yb3+、Nd3+ 和 Dy3+ 配合物的合成、热、光物理和生物学特性

摘要 六种新型镧系配合物，[Ln(NO3)2(L1H2)](NO3).xCHCl3.yH2O {Ln = Yb (1), x = 1, y = 2; Nd (3), x = 2, y = 3 和 Dy (5), x = 2, y = 2} 和​​ [Ln(NO3)2(L2H2)](NO3).xCHCl3 {Ln = Yb (2), x = 1; Nd (4), x = 2 和 Dy (6), x = 2}，由 NNNOO-供体五齿席夫碱配体 N,N'-双(3-甲氧基水杨烯)-2,2'-二氨基乙胺 (L1H2) 制备和 N,N'-双(2-羟基萘)-2,2'-二氨基乙胺 (L2H2)。这些合成的配合物通过元素分析、FT-IR、1H NMR、UV-vis 光谱和质谱进行了表征。采用TGA技术研究了配合物的热特性。在 DMSO 溶液中在 320 nm 激发波长下观察配体 L1H2 和 L2H2 及其 Ln(III) 配合物的荧光发射特性表明配体有利于能量转移到 Ln(III) 配合物的发射能级。使用配体及其 Yb((III) 配合物的密度泛函理论进行计算计算，以获得优化的分子几何形状、最高占据分子轨道、最低未占据分子轨道和其他参数。席夫碱、金属盐及其 Ln (III) 筛选复合物对金黄色葡萄球菌、粪肠球菌、大肠杆菌和伤寒沙门氏菌菌株的体外抗菌研究。抗菌研究的结果表明，镧系元素配合物比配体和金属盐具有更强的杀菌性能。图形概要