Theoretical calculations for new coumarin Schiff base complexes as candidates for in vitro and in silico biological applications

The Schiff base (Sb) formed by the condensation of 8-acetyl-7-hydroxy-4-methyl coumarin and sulfaclozine was used for the preparation of [Cu2(CH3COO)3(Sb)(H2O)] (Cu2-Sb) and [Pd2(OH)3(Sb)(H2O)]·2H2O (Pd2-Sb) complexes. Also, the mixed ligand zinc complex, [(Sb)Zn(Cipro)]·4H2O, (Sb-Zn-Cipro) was prepared from (Sb) and ciprofloxacin. Many tools of analysis as elemental and spectral studies, in addition to thermogravimetry (TG), molar conductance, magnetic moment, X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning electron microscope (SEM), and electron spin resonance (ESR) measurements, were used to prove the complexes' composition. The morphology studies confirm the nanostructure of copper and palladium complexes. At the B3LYP/GENECP level, the optimal structure of the complexes was estimated using the 6-31G++(d, p) basis set for C, H, N, S, and O atoms and the Los Alamos National Laboratory double zeta (LANL2DZ) basis set for metal atoms. A distorted square planar geometry is presumed for (Pd2-Sb), and distorted tetrahedral geometry is presumed for (Cu2-Sb) and (Sb-Zn-Cipro). The in vitro examination of the antimicrobial activity of the complexes was performed. The cytotoxic effects of the (Pd2-Sb) and (Sb-Zn-Cipro) against MCF-7 (breast cancer) and HCT-116 (colon cancer) cell lines were achieved in vitro. The results showed that (Sb-Zn-Cipro) has the best biological activity. In view of this, the in silico binding mode of (Sb-Zn-Cipro) complex with Escherichia coli (KAS I-PDB ID-1FJ4), Staphylococcus aureus tyrosyl-tRNA synthetase (PDB id: 1JIJ), yeast-specific serine/threonine protein phosphatase (PPZ1) of Candida albicans (PDB ID: 5JPE), breast cancer mutant oxidoreductase (PDB ID: 3HB5), and colon cancer human cyclin-dependent kinase 2; CDK2 (PDB ID: 6GUE) was performed using molecular docking.