Synthesis,characterization, and biological screening of metal complexes of novel sulfonamide derivatives: Experimental and theoretical analysis of sulfonamide crystal |
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Authors: | Sajjad H Sumrra Abrar U Hassan Muhammad Imran Muhammad Khalid Ehsan U Mughal Muhammad N Zafar Muhammad N Tahir Muhammad A Raza Ataualpa AC Braga |
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Institution: | 1. Department of Chemistry, University of Gujrat, Gujrat, 50700 Pakistan;2. Department of Chemistry, Faculty of Science, King Khalid University, Abha, 61413 Saudi Arabia;3. Department of Chemistry, Khwaja Fareed University of Engineering & Information Technology, Rahim Yar Khan, 64200 Pakistan;4. Department of Chemistry, Quaid-i-Azam University, Islamabad, 45320 Pakistan;5. Department of Physics, University of Sargodha, Sargodha, Pakistan;6. Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Prof.LineuPrestes, 748, São Paulo, 05508-000 Brazil |
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Abstract: | This study reports the synthesis of sulfonamide-derived Schiff bases as ligands L 1 and L 2 as well as their transition metal complexes VO(IV), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II)]. The Schiff bases (4-{E-(2-hydroxy-3-methoxyphenyl)methylidene]amino}benzene-1-sulfonamide ( L 1 ) and 4-{(2-hydroxy-3-methoxyphenyl)methylidene]amino}-N-(5-methyl-1,2-oxazol-3-yl)benzene-1-sulfonamide ( L 2 ) were synthesized by the condensation reaction of 4-aminobenzene-1-sulfonamide and 4-amino-N-(3-methyl-2,3-dihydro-1,2-oxazol-5-yl)benzene-1-sulfonamide with 2-hydroxy-3-methoxybenzaldehyde in an equimolar ratio. Sulfonamide core ligands behaved as bidentate ligands and coordinated with transition metals via nitrogen of azomethine and the oxygen of the hydroxyl group. Ligand L 1 was recovered in its crystalline form and was analyzed by single-crystal X-ray diffraction technique which held monoclinic crystal system with space group (P21/c). The structures of the ligands L 1 and L 2 and their transition metal complexes were established by their physical (melting point, color, yields, solubility, magnetic susceptibility, and conductance measurements), spectral (UV–visible UV–Vis], Fourier transform infrared spectroscopy, 1H NMR, 13C NMR, and mass analysis), and analytical (CHN analysis) techniques. Furthermore, computational analysis (vibrational bands, frontier molecular orbitals (FMOs), and natural bonding orbitals NBOs]) were performed for ligands through density functional theory utilizing B3LYP/6-311+G(d,p) level and UV–Vis analysis was carried out by time-dependent density functional theory. Theoretical spectroscopic data were in line with the experimental spectroscopic data. NBO analysis confirmed the extraordinary stability of the ligands in their conjugative interactions. Global reactivity parameters computed from the FMO energies indicated the ligands were bioactive by nature. These procedures ensured the charge transfer phenomenon for the ligands and reasonable relevance was established with experimental results. The synthesized compounds were screened for antimicrobial activities against bacterial (Streptococcus aureus, Bacillus subtilis, Eshcheria coli, and Klebsiella pneomoniae) species and fungal (Aspergillus niger and Aspergillus flavous) strains. A further assay was designed for screening of their antioxidant activities (2,2-diphenyl-1-picrylhydrazine radical scavenging activity, total phenolic contents, and total iron reducing power) and enzyme inhibition properties (amylase, protease, acetylcholinesterase, and butyrylcholinesterase). The substantial results of these activities proved the ligands and their transition metal complexes to be bioactive in their nature. |
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Keywords: | biological screening crystal structure DFT study sulfonamide transition metal complexes |
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