Synthesis, crystal structure, spectral and DFT studies of potent isatin derived metal complexes

The isatin-core in compounds offers exciting perspectives in medicinal and pharmacological research. The present study reports the successful development of new isatin-core transition metal based antibacterial complexes via conventional refluxing method. The bidentate nature of as-synthesized isatin-core ligand was confirmed using various analytical techniques such as FTIR, H-1 NMR, C-13 NMR, EIMS, and single crystal X-ray diffraction. The computed analysis i.e. IR, UV-Visible, NBO (Natural Bond Orbital) and FMO (Frontier Molecular Orbital) of crystalline isatin-core ligand reflect its dimer nature and predict the conjugative interaction among molecules. Moreover, metal complexes of isatin-core ligand using metallic salts of first transition series i.e. VO(IV), Cr(III), Mn(II), Fe(II), Co(ll), Ni(II), Cu(II) and Zn(II) were prepared and further screened against bacterial strains. Octahedral geometry was proposed for all the complexes except vanadium which had square-pyramidal geometry. All the as-prepared metal complexes are found potentially active entities against both of the gram-positive and gram-negative bacterial strains. Additionally, the bacterial screened data revealed that metal complexes have better bactericidal activities compared to their parent ligand. (C) 2018 Elsevier B.V. All rights reserved.