Bioactive Co(II), Ni(II), and Cu(II) Complexes Containing a Tridentate Sulfathiazole-Based (ONN) Schiff Base

Abstract

New Co(II), Ni(II), and Cu(II) complexes were synthesized with the Schiff base ligand obtained by the condensation of sulfathiazole with salicylaldehyde. Their characterization was performed by elemental analysis, molar conductance, spectroscopic techniques (IR, diffuse reflectance and UV–Vis–NIR), magnetic moments, thermal analysis, and calorimetry (thermogravimetry/derivative thermogravimetry/differential scanning calorimetry), while their morphological and crystal systems were explained on the basis of powder X-ray diffraction results. The IR data indicated that the Schiff base ligand is tridentate coordinated to the metallic ion with two N atoms from azomethine group and thiazole ring and one O atom from phenolic group. The composition of the complexes was found to be of the [ML2]∙nH2O (M = Co, n = 1.5 (1); M = Ni, n = 1 (2); M = Cu, n = 4.5 (3)) type, having an octahedral geometry for the Co(II) and Ni(II) complexes and a tetragonally distorted octahedral geometry for the Cu(II) complex. The presence of lattice water molecules was confirmed by thermal analysis. XRD analysis evidenced the polycrystalline nature of the powders, with a monoclinic structure. The unit cell volume of the complexes was found to increase in the order of (2) < (1) < (3). SEM evidenced hard agglomerates with micrometric-range sizes for all the investigated samples (ligand and complexes). EDS analysis showed that the N:S and N:M atomic ratios were close to the theoretical ones (1.5 and 6.0, respectively). The geometric and electronic structures of the Schiff base ligand 4-((2-hydroxybenzylidene) amino)-N-(thiazol-2-yl) benzenesulfonamide (HL) was computationally investigated by the density functional theory (DFT) method. The predictive molecular properties of the chemical reactivity of the HL and Cu(II) complex were determined by a DFT calculation. The Schiff base and its metal complexes were tested against some bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis). The results indicated that the antibacterial activity of all metal complexes is better than that of the Schiff base.

Production and Characterization of Palm Oil Based Epoxy Biocomposite by RSM Design

“…However, the peak formation of the oxirane group at 833 cm -1 supports the expected structure [60]. The peaks at 3357 and 3269 cm -1 observed in MPO spectrum belong to the -SO 2 -N-H group [61][62][63]. The observation of 1367 and 1228 cm -1 asymmetric stretching peaks of -SO 2 confirms the binding [64].…”

Copper-Coordinated Thiazoles and Benzothiazoles: A Perfect Alliance in the Search for Compounds with Antibacterial and Antifungal Activity

“…Additionally, Tz-31 was reported with a tetragonally distorted octahedral geometry and was tested against some bacteria strains (E. coli, P. aeruginosa, S. aureus and B. subtilis) by the well diffusion method. Coordination resulted in excellent inhibition in bacteria (40-45 mm), while ligand showed moderate inhibition (30-35 mm) [96].…”

Synthetic methodologies and pharmacological applications of sulphonamide containing Schiff bases and their metal complexes: A comprehensive review

“…The Cu complex showed 40, 45, 42 and 43 mm of zone of inhibition, Ni complex showed 33, 37, 36 and 37 mm of zone of inhibition and Co complex showed 35, 40, 37 and 38 mm of zone of inhibition against E. coli, S. aureus, B. subtilis and P. aeruginosa. 16 The results showed that the metal complexes were more efficient than the parent ligand (Figure 6). 17 To a hot magnetically stirred dioxane Schiff bases, Cu, Co, Ni and Zn salts were added and refluxed for 2 h. For Schiff base ligands and metal complexes, in vitro antibacterial activity was determined against bacterial strains namely E. coli, Shigella flexneri, P. aeruginosa and S. typhi and the antifungal activity was determined against fungal strains namely C. albicans, Candida glabrata, A. flavus, Fusarium solani and Microsporum canis,.…”