Synthesis, spectroscopic characterization, and thermal studies of novel Schiff base complexes: theoretical simulation studies on coronavirus (COVID-19) using molecular docking

Abstract

Novel Schiff base ligand was prepared by the condensation of 2,2-(ethylenedioxy)bis(ethylamine) and imidazole-2-carboxaldehyde in a 1:2 ratio, and its complexes with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), and Cd(II) metal ions were synthesized in a 1:1 ratio. Various methods were used to identify the Schiff base ligand and complexes. Characterization techniques such as infrared, UV, and 1 H NMR spectral tests, elemental analysis, molar conductivity, magnetic properties, thermal analysis, BET surface area, and theoretically by DFT were used to help further understanding of the complex structures. For all complexes, the ligand behaved as a neutral tetradentate ligand with NOON donor atoms and spectroscopic studies indicated an octahedral structure. The electrolytic behavior of the complexes was revealed by the molar conductivity measurements. In addition, thermogravimetric analysis was used to investigate the decomposition of the complexes and Schiff base ligand. According to the results obtained, the antibacterial activity of the metal complexes is higher than that of the Schiff base ligand against one or more bacterial species. The results showed that Cd(II) complex exhibits enhanced activity against Aspergillus flavus and Ni(II) complex against Candida albicans than the standard drug ketoconazole. The Mn(II) complex had stronger activity against human breast cancer cell line (MCF-7) than the other complexes. Antiviral drug development is critical in the latest outbreak of a novel coronavirus (SARS-CoV-2). The new coronavirus was screened using molecular docking. Supplementary Information The online version contains supplementary material available at 10.1007/s13738-021-02359-w.

Design, Structural Inspection and Bio-Medicinal Applications of Some Novel Imine Metal Complexes Based on Acetylferrocene

“…The first two bands were allocated to n-π* transition of the benzene ring [ 3 ] which shifted to 233–290 nm in the metal chelates. The third band was attributed to π-π* transition of the imine group [ 52 ] which shifted to 302–366 nm in all-metal chelates except for Mn(II) and Ni(II) cation chelates, which disappeared. The fourth band was assigned to charge transfer transitions [ 52 ] from aromatic ring to imine group that disappeared in the metal chelates.…”

“…The third band was attributed to π-π* transition of the imine group [52] which shifted to 302-366 nm in all-metal chelates except for Mn(II) and Ni(II) cation chelates, which disappeared. The fourth band was assigned to charge transfer transitions [52] from aromatic ring to imine group that disappeared in the metal chelates. Thermal decompositions were done under an air environment at a rate of heating 10 • C min −1 .…”

Development of Metal Complexes for Treatment of Coronaviruses

“…(Mn(L) H 2 O Cl) Cl. 3H 2 O had the strongest binding while having the lowest energy (−10.10 kcal/mol) [ 99 , 100 ].…”

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

“…Additionally, corroles are corrins' aromatic derivatives [55]. Schiff bases have wide industrial uses and biological applications, such as antidiabetic, anti-inflammatory, and antimalarial activities [43,[56][57][58][59][60][61][62][63].…”

“…e IC 50 results were determined by percentage plot of the cell inhibition against concentration by the nonlinear regression analysis [22]. Ahmed et al defined IC 50 values as the concentrations of the Schiff base ligand (L) and its metal complexes needed to produce 50% cell growth inhibition [58]. e mean IC 50 is the material concentration that reduces cell growth by 50% under the experimental conditions and is the average of triplicate measurements that were reproducible and statistically significant.…”