Designing of some novel Pd(II), Ni(II) and Fe(III) complexes: Synthesis, structural elucidation, biomedical applications, DFT and docking approaches against Covid-19

A new class of bio-active Pd(II), Ni(II) and Fe(III) complexes [Pd(L)(COOCH3)2](H2O)2, [Ni(L)2(NO3)2](H2O), and [Fe(L)2(NO3)2](NO3)(H2O)2 have been constituted by utilizing the guanidine-based ligand (BSG) = NBenzothiazol-2-yl-guanidine. The micro-analytical results of the structural characteristics were validated by UV-Visible, FT-IR, 1H-13C NMR, elemental analysis, molar conductance, TGA, mass spectral, XRD data and magnetic susceptibility measurements. The Ni(II) and Fe(III) metal chelates depicted an octahedral geometry, while the Pd(II) metal chelate display an square planar geometry. The optimized molecular structures have been scrutinized by DFT method. In vitro anticancer activities of the BSG, Pd(II), Ni(II) and Fe(III) metal chelates were evaluated on HCT-116 colon cancer cells, HepG-2 hepatic cellular carcinoma cells, and MCF-7 breast carcinoma cells and biocompatibility characteristics were determined by using the Sulforhodamine B (SRB) assay. According to the findings of the study, Pd(II) metal chelates showed considerable anticancer properties in the breast carcinoma MCF-7 cancer cells. The antioxidant capacities of metal complexes were validated using the DPPH free radical scavenging method. The complexes have good antioxidant activities with the DPPH radical. Also, the synthesized products were investigated for their antibacterial and antifungal activities against bacterial organisms including (S. marcescence, M. luteus, and E. coli) in addition to fungi (A. flavus, C. candidum, and F. oxysporum). Among all the evaluated compounds, it was found that BSGPd possessed remarkable antibacterial activity toward M. luteus and antifungal activity toward G. candidum. The demonstrated acceptable bioactivities for several of these compounds support the basic design concept of integrating essential bioactive patterns for potential therapeutic benefit. Furthermore, a molecular docking (an in silico approach) study was performed with 7BQY to check the activity of the investigated compounds against COVID-19.

Automated summary

A new class of bio-active Pd(II), Ni(II) and Fe(III) complexes were synthesized using the guanidine-based ligand (BSG). The structural characteristics were validated by various analytical techniques and the complexes were evaluated for their anticancer, antioxidant, antibacterial, and antifungal activities. Among them, the Pd(II) complex showed significant anticancer activity in MCF-7 breast carcinoma cells.