Abstract Herein, [M(HL)2(H2O)2]NO3·2H2O (M = Sm (III) /or Eu (III); HL = 4-(2-hydroxy benzylidene acetohyrazide)-7-hydroxy coumarin) were synthesized and characterized using several spectroscopic methods. The complexes stoichiometry with molar ratio 2L:1M were confirmed by Job's method. Tridentate ligand (HL) was coordinated to the lanthanide ions Sm(III) or Eu(III) through azomethine nitrogen atom, phenolic oxygen of hydrazide, and ketonic oxygen of the amide group. The photophysical properties of the ligand and its complexes were studied in different organic solvents and their fluorescence quantum yields were determined as well. Strong fluorescence emissions to red shifts of europium complex were observed at 580, 593, 617, 653, 693, 704 nm which were attributed to Eu(III) emission of 5D0→7F0, 5D0→7F1, 5D0→7F2, 5D0→7F3, 5D0→7F4, and 5D0→7F5, respectively. First-principles DFT calculations were performed to evaluate the optimized structure and separation energies of the HL compound, using the B3LYP/6-311++g(d,p) basis set. Molecular docking studies were carried out to predict the binding modes between the HL compound and active site of the xanthine oxidase enzyme [EC# (1.17.3.2) PDB ID: 1FIQ] which produced from liver patients of hepatitis C. The observed activity of the HL gave rise to the conclusion that it might exert its action through inhibition of the xanthine oxidase enzyme.

中文翻译：

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新合成香豆素配体的 Sm(III) 和 Eu(III) 配合物的光物理、DFT 和分子对接研究

摘要 本文合成了[M(HL)2(H2O)2]NO3·2H2O(M=Sm(III)/或Eu(III)；HL=4-(2-羟基亚苄基乙酰基酰肼)-7-羟基香豆素)并使用几种光谱方法进行表征。摩尔比为 2L:1M 的配合物通过 Job 方法确认。三齿配体（HL）通过偶氮甲碱氮原子、酰肼的酚氧和酰胺基的酮氧与镧系离子Sm（III）或Eu（III）配位。在不同的有机溶剂中研究了配体及其配合物的光物理性质，并测定了它们的荧光量子产率。在 580、593、617、653、693、704 nm 处观察到对铕络合物红移的强烈荧光发射，这归因于 5D0→7F0、5D0→7F1、5D0→7F2、5D0→7F3 的 Eu(III)发射， 5D0→7F4，和 5D0→7F5，分别。使用 B3LYP/6-311++g(d,p) 基组，进行第一性原理 DFT 计算以评估 HL 化合物的优化结构和分离能。进行分子对接研究以预测 HL 化合物与黄嘌呤氧化酶 [EC# (1.17.3.2) PDB ID: 1FIQ] 活性位点之间的结合模式，该酶由丙型肝炎患者产生。 HL 得出的结论是它可能通过抑制黄嘌呤氧化酶发挥作用。