Synthesis, Characterization,Computational Studies and Antimicrobial activity evaluation of Mixed ligand‐Metal complexes of selected thiosemicarbazones

Abstract The current work reports the synthesis of mixed ligand‐metal complexes of (2‐(2‐oxoacenaphthylen‐1 ylidene)hydrazinecarbothioamide) (L1) and carbamothioyl‐2‐chloronicotinohydrazonic acid (L2) and imidazole (im), triphenylphosphine (PPh 3 ) and pyridine (py) ligands with Cu (II), Zn (II), Fe (II) and Co (II) salts.The chacterization was done through FT‐IR, NMR, UV‐visible, and elemental analysis. The X‐ray diffraction (XRD) patterns of Cu(L1)(im) 2 (SO 4 ) demonstrated the crystalline morphology. In the FT‐IR spectra of the ligands, the characteristic frequencies corresponding to ν(C=N) (imine) and ν(C=S) (thiocarbonyl) were observed around 1650 and 1130 cm −1 respectively, which shifted upon complexation. In the 1 H NMR spectra, the peak due to the NH proton was observed downfield, whereas that of ‐NH 2 was observed comparatively upfield owing to its secondary amine nature. The molecular docking was performed against transforming growth beta (tgf‐β), protease of SARS‐CoV‐2 (M pro ) and aspartate kinase (Asp) kinase.The molecular simulation with the docked complex of Zn(L2)(py) 2 (SO 4 ) and Zn(L1)(PPh 3 ) 2 (SO 4 ) with Asp kinase showed significant stability during the simulation time of 100 ns. The relative free energies of the simulated complexes were calculated with the molecular mechanics Poison‐Boltmann surface area (MM‐PBSA). The complexes were tested against ten bacterial strains and showed enhanced antibacterial activity than the ligands. Cu(L1)(im) 2 (SO 4 ), Zn(L1)(im) 2 (SO 4 ), Fe(L1)(im) 2 (SO 4 ) and Co(L1)(im) 2 (Cl 2 ) were found to be active against E.coli .