Synthesis, Spectral, Thermal and Biological Studies of Some Transition and Inner Transition Schiff base Metal Complexes

Abstract

The new bidentate Schiff base ligand (L) named N 1 -(diphenylmethylene)naphthalene-1,8-diamine was prepared by the condensation reaction of benzophenone and 1,8-naphthylenediamine. The complexes with Mn(II), Ni(II), Zn(II), La(III), Er(III), and Yb(III) metal ions were prepared and characterized by using elemental analyses (C, H, N and M), FT-IR, 1 H NMR, molar conductivity, magnetic moment, UV-Vis, mass and scanning electron microscope (SEM). The temperatures of decomposition of the Schiff base ligand and metal complexes were investigated using thermal analyses. The metal complexes were found to have the formulae [M(L)(H2O)3Cl]Cl.nH2O (M = Mn(II) (n = 4); Ni(II) (n = 2))], [Zn(L)(H2O)2Cl2] and [M(L)(H2O)2Cl2]Cl (M = La(III), Er(III) and Yb(III)) according to the elemental analyses data. The geometrical structure of all complexes was found to be octahedral. The molar conductivity of the complexes in DMF indicated the electrolytic nature of all complexes except Zn(II) complex was non-electrolyte. From the spectroscopic data, the Schiff base ligand acts as NNbidentate ligand. The biological and anticancer activities of the Schiff base ligand and its complexes were investigated against two bacterial strains, two fungal strains and breast cancer cell line (MCF-7). Docking studies were performed to study the possible interaction between the Schiff base ligand with the active sites of the 3HB5 and 5JPE receptors.

Manganese Schiff Base Complexes, Crystallographic Studies, Anticancer Activities, and Molecular Docking

“…According to Khalil et al, the potential cytotoxicity of their synthesized compounds was studied with Skehan and Storeng method [35]. As a result, cells were inoculated with a 96-multiwell plate (104 cells/well) for 24 h before treatment with the synthesized compounds to permit adhesion of the cell to the wall plate.…”

“…Acetic acid was used to wash excess stain and the attached stain was recovered with tris-ethylenediaminetetraacetic acid (tris-EDTA) buffer [35]. e optical density (O.D.)…”

“…Similar to Khalil et al, Ahmed et al, as well as Mohamed and Ahmed, studied the cytotoxicity of their synthesized compounds with SRB assay using Skehan and Storeng method [35,58,59].…”

“…In the case of metal complexes intervention in docking process, they belong to ligandprotein docking. Based on importance, Khalil et al stated the importance of molecular docking studies to predict the potential binding modes of the most potent compounds with the receptor proteins of breast cancer mutant oxidoreductase whose crystal structure was downloaded from the Protein Data Bank (https://www.rcsb.org/) with identification of PDB ID: 3HB5 [35]. Additionally, Khalil's computational study was aimed at evaluating the binding free energy of the inhibitor inside the macromolecule.…”

“…In view of the fact that chelation therapy eases manganese challenges, crystallographic studies were used to observe the mechanism of coordination of the Schiff base to the manganese(II) and (III) ions, while molecular docking studies were reported first to identify the orientation, as well as conformation of the ligand with the receptor, and second to study the potential interaction between the Schiff base ligand or manganese Schiff base complexes and the active sites of virtual cancer cell line such as the 3HB5 receptor to obtain lead optimization [35].…”