A new class of pyridazine-based six Iron(II), Nickel(II) and Copper(II) metal complexes of (E)-2-(6-chloropyridazin-3-yl)-1-(1-(pyridin-2-yl)ethylidene)hydrazine ligand (L1)(1) derived from condensation of 2-(6-chloropyridazin-3-yl)hydrazine and pyridine-2-acetaldehyde were synthesized in 1:1 and 1:2 molar ratio with ligand and characterized by UV–visible, ¹H- and ¹³C-NMR, FT-IR, mass and EPR spectroscopy, elemental analysis and molar conductance. The spectroscopic evidence specifies that the ligands behave as a tridentate ligand through the nitrogen atom of pyridine-2-acetaldehyde, nitrogen atoms of azomethine group and pyridazine ring. The mass spectra demonstrated that the complexes have prepared in 1:1 and 1:2 molar ratio with ligand and suitable metals salts. From the ESR spectroscopy, confirmed that the Cu(L1)(4) complex had the square planar geometry, whereas Cu(L1)₂(7) complex had distorted octahedral geometry. The ligand and its six metal complexes were evaluated for their in vitro antibacterial activity against Staphylococcus aureus (MTCC 96), Streptococcus pyogenes (MTCC 442), Escherichia coli(MTCC 443), Pseudomonas aeruginosa (MTCC 1688) strains, and in vitro antifungal activity against Candida albicans (MTCC 227), Aspergillus niger (MTCC 282), and Aspergillus clavatus (MTCC 1323) strains by using micro-broth dilution method against standard antibiotics Gentamycin, Ampicillin, Chloramphenicol, Ciprofloxacin, Norfloxacin, and antifungal agents Nystatin and Griseofulvin. Cytotoxicity assays against human colon cancer MiaPaCa-2 and PanC-1 cell lines in vitro were completed for ligand (L1) by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium by (MTT) method. Finally, the optimized structures of the ligand and its complexes have been used to accomplish molecular docking studies with receptors of DNA Gyrase (PDB ID-1aj6) enzyme to determine the most preferred mode of interaction.

Graphical abstract

中文翻译：

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哒嗪基配体的过渡金属配合物：合成、表征、生物活性和分子对接研究

一类新型哒嗪基六种铁(II)、镍(II)和铜(II)金属配合物(E) -2-(6-氯哒嗪-3-基)-1-(1-(pyridin-2)由2-(6-氯哒嗪-3-基)肼与吡啶-2-乙醛以1:1和1:2摩尔比缩合得到的-基)亚乙基)肼配体(L1)(1)与配体合成通过 UV-可见光、¹ H- 和^{13进行表征}C-NMR、FT-IR、质谱和 EPR 光谱、元素分析和摩尔电导。光谱证据表明该配体通过吡啶-2-乙醛的氮原子、甲亚胺基团和哒嗪环的氮原子表现为三齿配体。质谱表明配合物与配体和合适的金属盐以1:1和1:2摩尔比制备。ESR光谱证实Cu(L1)(4)配合物具有正方形平面几何形状，而Cu(L1) ₂ (7)配合物具有扭曲的八面体几何形状。评估了配体及其六种金属配合物对金黄色葡萄球菌（MTCC 96）、化脓性链球菌（MTCC 442）、大肠杆菌的体外抗菌活性(MTCC 443)、铜绿假单胞菌(MTCC 1688) 菌株，以及针对白色念珠菌(MTCC 227)、黑曲霉(MTCC 282) 和棒曲霉的体外抗真菌活性(MTCC 1323) 菌株采用微量肉汤稀释法针对标准抗生素庆大霉素、氨苄青霉素、氯霉素、环丙沙星、诺氟沙星以及抗真菌剂制霉菌素和灰黄霉素。通过 3-(4,5-二甲基-2-噻唑基)-2,5-二苯基-2H-四唑完成配体 (L1) 对人结肠癌 MiaPaCa-2 和 PanC-1 细胞系的体外细胞毒性测定（ MTT）方法。最后，配体及其复合物的优化结构已用于完成与 DNA 旋转酶 (PDB ID-1aj6) 酶受体的分子对接研究，以确定最优选的相互作用模式。

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