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A new class of homoleptic metal(II) complexes of general formula [M(L1–4)2]2Cl in which L1=1‐([1,1′‐biphenyl]‐4‐yl)‐N‐(2‐((‐pyridin‐2‐ylmethylene)amino)ethyl)methanimine, L2=1‐([1,1′‐biphenyl]‐4‐yl)‐N‐(2‐((‐pyridin‐2‐ylmethylene)amino)phenyl)methanimine, L3=1‐([1,1′‐biphenyl]‐4‐yl)‐N‐(2‐((‐pyridin‐2‐ylmethylene)amino)‐4‐nitrophenyl)methanimine and L4=4‐(([1,1′‐biphenyl]‐4‐ylmethylene)amino)‐3‐((−pyridin‐2‐ylmethylene)amino)benzophenone, and M=Ni(II) (1–4), Cu(II) (5–8) and Zn(II) (9–12) have been synthesized and characterized. The IR spectra reveal the involvement of azomethine and 2‐formylpyridine ring nitrogen atoms in chelation. The UV‐Vis and EPR spectral studies envisage distorted octahedral geometry around metal(II) ion. All the complexes were stable for 72 h in biologically relevant solutions, and copper(II) complexes were reduced to Cu+ center in the presence of ascorbic acid solution. The binding studies of complexes with calf thymus DNA (CT‐DNA) indicate groove mode of binding, and the complexes 3, 7 and 11 containing the 4‐nitrophenyl substituent exhibit the highest binding affinity than the other complexes. Furthermore, the spectral studies also revealed the interaction of complexes with BSA through static mechanism. In vitro cytotoxicity activity of the complexes was screened against human lung adenocarcinoma (A549) and breast adenocarcinoma (MCF‐7) cancerous, and normal murine fibrosarcoma (L929) cell lines. The molecular docking studies of the homoleptic metal(II) complexes show hydrophobic, π–π, σ–π and hydrogen bonding interactions with EGFR/VEGFR2 kinase receptors. [ABSTRACT FROM AUTHOR]

A series of 12 salicylidene‐based homoleptic nickel(II), copper(II) and zinc(II) complexes with the general formula [M(L1–4)2] (1–12) containing the tridentate ligands 2‐(((2‐(([1,1′‐biphenyl]‐3‐ylmethylene)amino)phenyl)imino)methyl)phenol (HL1), 2‐(((2‐(([1,1′‐biphenyl]‐3‐ylmethylene)amino)phenyl)imino)methyl)‐4‐methoxyphenol (HL2), 2‐(((2‐(([1,1′‐biphenyl]‐3‐ylmethylene)amino)phenyl)imino)methyl)‐4‐ethoxyphenol (HL3) and 2‐(((2‐(([1,1′‐biphenyl]‐3‐ylmethylene)amino)phenyl)imino)methyl)‐4‐nitrophenol (HL4) have been synthesized and characterized by spectroscopic analysis. The tridentate nature of the ligands form an octahedral geometry around the central metal ion through the phenolic oxygen via deprotonation and two azomethine nitrogen atoms. Further, the charge transfer transitions taking place in the complexes have been explained using HOMO‐LUMO analysis. The in vitro cytotoxicity activity screened by WST assay against human metastatic (MDA‐MB‐231), hepatoma (HepG2) and colorectal adenocarcinoma (CaCo2) cancerous, and normal mouse fibroblast (NIH3T3) cell lines showed higher activity for the complexes 2, 6 and 10 with respect to the standard drug 5‐fluorouracil. The AO/EB, PI, Rh123 and DCFH‐DA staining results indicated that the complexes induced anticancer activity through apoptosis. Furthermore, the complexes interact with FGFR and P13Kγ kinase receptors through the hydrophobic, hydrogen bonding, π–π, σ–π, van der Waals and electrostatic interaction. [ABSTRACT FROM AUTHOR]

In this study, a series of new heteroleptic silver(I), nickel(II), and copper(II) complexes of the type [M(L1–3)(Cfx)n] (1–9), where L1–3 = N4‐substituted thiosemicarbazones (TSCs), Cfx = ciprofloxacin, M = Ag(I), Ni(II), or Cu(II), and n = 1 or 2, have been synthesized and characterized by spectral methods. The spectral data of the complexes suggest bidentate behavior of the TSC ligand, which coordinate with metal ion through thione sulphur and hydrazine nitrogen atoms, and neutral bidentate behavior of the ciprofloxacin drug that coordinates with metal ion through pyridone oxygen and one of the carboxylate oxygen atoms. The structural properties of the silver(I) complexes (1–3) were studied by density functional theory calculations, which indicate the distorted tetrahedral geometry with lower energy gap for complex 3. All the heteroleptic complexes were screened for their in vitro anti‐proliferative activity against four cancerous (lung [A549], estrogen negative [MDA‐MB‐231], estrogen positive [MCF‐7] and Henrietta's cancer cells [HeLa]), and one non‐cancerous (non‐tumorigenic human breast epithelial cell line [MCF‐10a]) cell lines by MTT reduction assay. The obtained results revealed the lower activity of silver(I) complexes and higher activity of copper(II) complexes against the tested cancer cell lines. The complexes 6 and 9 induce apoptosis in MDA‐MB‐231 cells, which was evidenced by acridine orange/ethidium bromide staining method. The molecular docking studies revealed hydrogen bonding and hydrophobic interactions between the complexes and the epidermal growth factor receptor. The in silico analysis of the complexes for Lipinski's "rule of five" and absorption, distribution, metabolism, and excretion properties predicted the drug‐likeness of the synthesized complexes. [ABSTRACT FROM AUTHOR]