Molecular structure, molecular docking, thermal, spectroscopic and biological activity studies of bis‐Schiff base ligand and its metal complexes

Abstract

Mn(II) ions were synthesized from the ligand [4,4′-((((ethane-1,2-diylbis(oxy)) bis(2,1-phenylene))bis(methanylylidene))bis(azanylylidene))diphenol]ethane (H 2 L) derived from the condensation of bisaldehyde and 4-aminophenol. Microanalysis, magnetic susceptibility, infrared, 1 H NMR and mass spectroscopies, molar conductance, X ray powder diffraction and thermal analysis were used to confirm the structure of the synthesized chelates. According to the data obtained, the composition of the 1:1 metal ion-bis-Schiff base ligand was foundand Mn(II), n = 2; Fe(III), n = 3). Magnetic susceptibility measurements and reflectance spectra suggested an octahedral geometry for the complexes. Central metals ions and bis-Schiff base coordinated together via O2 and N2 donor sites which as evident from infrared spectra. The Gaussian09 program was applied to optimize the structural formula for the investigated Schiff base ligand. The energy gaps and other important theoretical parameters were calculated applying the DFT/B3LYP method. Molecular docking using AutoDock tools was utilized to explain the experimental behaviour of the Schiff base ligand towards proteins of Bacillus subtilis (5 h67), Escherichia coli (3 t88), Proteus vulgaris (5i39) and Staphylococcus aureus (3ty7) microorganisms through theoretical calculations. The docked protein receptors were investigated and the energies of hydrogen bonding were calculated. These complexes were then subjected to in vitro antibacterial studies against several organisms, both Gram negative (P. vulgaris and E. coli) and Gram positive (S. pyogones and B. subtilis). The ligand and metal complexes exhibited good microbial activity against the Gram-positive andGram-negative bacteria.KEYWORDS bioinorganic chemistry, bis-Schiff base ligand, in vitro biological activity, IR spectroscopy, metal complexes, thermal analysis

Structural, spectroscopic, molecular docking, thermal and DFT studies on metal complexes of bidentate orthoquinone ligand

“…The parameters of the kinetic thermodynamic were estimated graphically by employing the Coats–Redfern (CR) and the data were summarized in Table .…”

Spectroscopic, thermal, biological activity, molecular docking and density functional theoretical investigation of novel bis Schiff base complexes

“…The metal complexes of H 2 L was prepared by the addition of hot solution (60°C) of the appropriate metal chloride (0.664 mmol) in absolute ethanol (15 ml) to the hot solution (60°C) of the organic ligand (0.3 g H 2 L, 0.664 mmol) in ethanol and DMF (15 ml). The resulting mixture was heated with stirring till precipitates were formed . The precipitates were dried and weighed to calculate the yield.…”

“…Docking methodology aims to predict the experimental binding modes and affinities of small molecules within the binding site of particular receptor targets and is currently used as a standard computational tool in drug design for lead compound optimization and in virtual screening studies to find novel biologically active molecules. The basic tools of a docking methodology include a search algorithm and an energy scoring function for generating and evaluating ligand poses.…”

Synthesis, Spectral Characterization, Docking Analysis, DNA Binding/Cleavage, Antimicrobial and Cytotoxic Activity of New Dimeric Antipyrine-Schiff Base Metal Complexes

“…However, these four absorption bands are also observed in the electronic spectra of all synthesized complexes with slight shifts to the higher region in wavelength. This shift may be due to the alteration of molecular environment of Schiff base ligand after the chelation with metal ions [40][41][42]. The electronic spectra of the ligand and its dimeric Co(II) and Zn(II) complexes are shown in Fig.…”