Abstract
The present study advocates the combined experimental and computational study of metal-based aminothiazole-derived Schiff base ligands. The structure and electronic properties of ligands have been experimentally studied by spectroscopic methods (UV-Vis, FT-IR, 1H-NMR and 13C-NMR), mass spectrometry, elemental analysis and theoretically by density function theory (DFT). Computational calculations employing the B3LYP/6-31 + G(d,p) functional of DFT were executed to explore the optimized geometrical structures of ligands along with geometric parameters, molecular electrostatic potential (MEP) surfaces and frontier molecular orbital (FMO) energies. Global reactivity parameters estimated from FMO energy gaps signified the bioactive nature of ligands. The synthesized ligands were used for chelation with 3d-transition metals [VO(IV), Cr(III), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] in 1 : 2 (metal : ligand) molar ratio. The spectral and magnetic results confirmed the formation of octahedral geometry around all the divalent and trivalent metal centres, whereas the tetravalent vanadyl centres were confirmed to have square-pyramidal geometry. All the as-synthesized compounds were investigated for in vitro antibacterial potential against two Gram-negative (Salmonella typhimurium and Escherichia coli) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacteria. Antibacterial assay results displayed pronounced activity, and their activity is comparable to that of a standard drug (streptomycin). The antioxidant potential of these compounds was assessed by employing diphenyl picryl hydrazide radical scavenging activity. The results displayed that all the metal chelates have exhibited more bioactivity in contrast with free ligands. The chelation was the main reason for their enhanced bioactivity. These results indicated that the thiazole metal-based compounds could be exploited as antioxidant and antimicrobial candidates.
Highlights
Transition metal chelates of Schiff base ligands are of prodigious interest in the field of coordination chemistry [1]
The spectral data indicated that the ligands were coordinated with the 3d-metal ions by means of bidentate and tridentate approach using NN and NNO donor atoms
The physical properties in addition to the microanalytical details of the synthesized thiazole Schiff base ligands and their respective metal-based compounds are depicted in the electronic supplementary material, table S1
Summary
Transition metal chelates of Schiff base ligands are of prodigious interest in the field of coordination chemistry [1]. Metal-based thiazole-derived compounds display a variety of biological activities including anti-inflammatory, antioxidant and antitubercular [15] These compounds have been emerged as a novel class of strong antimicrobial marketers, which could be reported for inhibiting the bacteria with the help of hindering off the biosynthetic pathway of positive bacterial lipids and/or by other additional mechanism [16]. In the continuation of our ongoing research work on exploring the effective role of chelation on bioactive molecules [28], we report a new class of thiazole Schiff bases derived by the condensation reaction of two aminothiazole moieties with isatin and chloroisatin along with their transition metal complexes to scrutinize their antioxidant and antibacterial properties. The as-synthesized metal-based thiazole Schiff base ligands were characterized by computational and spectral studies, elemental analysis, magnetic and conductance measurements
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
