Homo- and heterometallic complexes of Zn(II), {Zn(II)Au(I)}, and {Zn(II)Ag(I)} with pentadentate Schiff base ligands as promising anticancer agents

Two families of homo- and heterometallic complexes, [Zn2L1(μ-OH)(H2O)2](ClO4)2, [Zn2L2(μ-OH)(H2O)2](ClO4)2, [Zn2L3(μ-OH)(H2O)2](ClO4)2, 1∞[{L1Zn2(μ-OH)}{μ-[Ag(CN)2]}](ClO4), [{L1Zn2(μ-OH)}2{μ-[Au(CN)2]}{[Au(CN)2]2}](ClO4)·H2O, 1∞[{L2Zn2(μ3-OH)}2(H2O){μ-[Ag(CN)2]}](ClO4)3·THF·0.5MeOH, 1∞[{L2Zn2(μ3-OH)}2(H2O){μ-[Au(CN)2]}](ClO4)3·THF·H2O, and 1∞[{L3Zn2(μ-OH)}{μ-[Ag(CN)2]}][Ag(CN)2]·H2O, respectively, have been synthesized and characterized. The Schiff bases used as ligands were obtained by condensation reactions of 2,6-diformyl-p-cresol with N,N-dimethyl-ethylenediamine (HL1), 2-aminomethyl-pyridine (HL2), and 2-aminoethyl-pyridine (HL3), respectively. The cytotoxic/cytostatic and genotoxic effects in cultured human MCF-7 (luminal type A breast cancer), MDA-MB-231 (triple negative breast cancer), HeLa (cervical carcinoma), and Lep-3 (non-tumor embryonal fibroblastoid cells) were studied. The investigations were performed by thiazolyl blue tetrazolium bromide test (MTT test), neutral red uptake cytotoxicity assay, crystal violet staining, hematoxylin and eosin staining, double staining with acridine orange and propidium iodide, AnnexinV/FITC, and Comet assay in short-term experiments (24-72 h, with monolayer cell cultures) as well as by 3D colony-forming method in long-term experiments (28 days, with 3D cancer cell colonies). The results obtained revealed that: (i) applied at a concentration range of 0.1-100 μg mL-1, the compounds investigated decrease in a time- and concentration-dependent manner the viability and/or proliferation of the treated cells; (ii) complexes of {Zn(II)Au(I)} show relatively higher cytotoxic/genotoxic activity and antitumor potential as compared to {Zn(II)Ag(I)}; (iii) some of the complexes demonstrate more pronounced cytotoxic potential than commercially available antitumor agents cisplatin, oxaliplatin, and epirubicin.

Structural topologies involving energetically significant antiparallel π-stacking and unconventional N(nitrile)⋯π(fumarate) contacts in dinuclear Zn(ii) and polymeric Mn(ii) compounds: antiproliferative evaluation and theoretical studies

Anticancer activities considering cell viability, apoptosis and molecular docking have been explored in dinuclear Zn(ii) and polymeric Mn(ii) compounds involving energetically significant unconventional N(nitrile)⋯π(fum) contacts.

Solvent-driven structural topologies in phenanthroline-based co-crystals of Zn(ii) involving fascinating infinite chair-like {[(bzH)4Cl2]2−}n assemblies and unconventional layered infinite {bz-H2O-Cl}n anion-water clusters: antiproliferative evaluation and theoretical studies

Anticancer activities considering cell cytotoxicity, apoptosis and molecular docking have been explored in Zn(ii) co-crystals of phenanthroline involving infinite chair-like assemblies and unconventional layered infinite anion-water clusters.

Coordination complexes of zinc and manganese based on pyridine-2,5-dicarboxylic acid N-oxide: DFT studies and antiproliferative activities consideration

We report here the design, synthesis, and antiproliferative activity of three coordination complexes [Mn₂(pydco)₂(bpy)₂(H₂O)₂]·2H₂O (1), [Zn(bpy)(Hpydco)₂] (2), and [Zn(bpy)Cl(Hpydco)]·2H₂O (3) (H₂pydco = pyridine-2,5-dicarboxylic acid N-oxide, bpy = 2,2'-bipyridine). Molecular structures of these complexes have been characterized by elemental analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis, and powder and single-crystal X-ray diffraction. According to the structural analysis, 1-3 are discrete complexes containing N- and O-donor ligands (bpy and pydco^2-) in which pydco^2- can be coordinated to the metal centres via the N-oxide oxygen and one carboxylate oxygen to generate a six-membered chelate ring. Also, these structures benefit from extensive intermolecular interactions such as hydrogen bonds and π-interactions which are the major forces to make them more stable in the solid state. The energetic features of the π-stacking interactions observed in compounds 1-3 have been computed and compared to the H-bonds. The interactions in the solid state have been also studied using the independent gradient model approach (IGM plot). The IGM-δg approach uses a new descriptor (δg) that locally represents the difference between a virtual upper limit of the electron density gradient and the true electron density gradient. This newly developed IGM methodology automatically extracts the signature of interactions between two given fragments. Finally, the antiproliferative properties of these complexes were tested on several cancer cell lines by MTT assay and flow cytometry. Also, to compare the antiproliferative activities of these complexes with common chemotherapy drugs, the antiproliferative property of cisplatin was evaluated as a reference and positive control.