New bioactive Pt(II) binary and ternary metal complexes with guaifenesin drug: Synthesis, geometrical structure, and spectroscopic and thermal characterization

Self Cite

A novel Schiff base ligand, namely 2,2′‐((1E,1′E)‐(1,3‐phenylenebis(azanylylidene))bis(methanylylidene))diphenol (H2L), was synthesized by condensation of m‐phenylenediamine and 2‐hydroxybenzaldehyde (in 1:2 ratio). Series of complexes were obtained from the reaction of La(III), Er(III) and Yb(III) chlorides with H2L. The ligand and complexes were characterized using elemental analysis, infrared, 1H NMR, UV–visible and mass spectroscopies, magnetic susceptibility and conductivity measurements and thermal analysis. Infrared and 1H NMR spectra indicated the coordination of the azomethine nitrogens and deprotonated phenolic oxygen atoms in a tetradentate manner (ONNO). The thermal behaviour of the complexes was studied from ambient temperature to 1000°C. The complexes were found to have water molecules of hydration and coordinated water molecules. The complexes were found to possess high biological activities against various organisms compared to the free ligand (Gram‐positive bacteria Staphylococcus aureus and Bacillus subtilis, Gram‐negative bacteria Salmonella sp., Escherichia coli and Pseudomonas aeruginosa and fungi Aspergillus fumigatus and Candida albicans). The more effective and probable binding modes between H2L with different active sites of colon cancer (PDB code: 2hq6) and lung cancer (PDB code: 1x2j) receptors were investigated using molecular docking studies.

Section: Resultsmentioning

confidence: 99%

Inner metal complexes of tetradentate Schiff base: Synthesis, characterization, biological activity and molecular docking studies

Diab

Mohamed

Mahmoud

et al. 2019

Self Cite

“…Docking methodology aims to predict the experimental binding modes and affinities of small molecules within the binding sites 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.…”

Section: Introductionmentioning

confidence: 99%

Coordination behaviour and biological activity studies involving theoretical docking of bis‐Schiff base ligand and some of its transition metal complexes

Zayed

Hindy

et al. 2018

Self Cite

The Schiff base ligand 1,2-bis(2-vinylphenoxy)ethane-4,6-diaminopyrimidine-2-thiol derived from the condensation of 4,6-diaminopyrimidine-2-thiol with bisaldehyde was synthesized and characterized. Coordination compounds of this Schiff base with transition metal cations Cd(II), Zn(II), Ni(II), Co(II), Mn(II), Cu(II) and Fe(III) were synthesized and characterized. Microanalytical data, magnetic moments, mass, 1 H NMR and infrared spectra, molar conductance measurements and thermal analyses were used to confirm the structures of the obtained Schiff base ligand and its chelates. According to the data obtained, the 1:1 general stoichiometric formulae of chelates are given by [M(HL)(H 2 O) 2 ]Cl 2 (M = Cd(II), Zn(II), Ni(II), Co(II), Mn(II), Cu(II)) and [Fe(HL)(H 2 O) 2 ]Cl 3 . The diffuse reflectance spectra and magnetic moment measurements suggest an octahedral geometry for the complexes. The bis-Schiff base ligand and metal ions are coordinated in a tetradentate manner via OO and NN donor sites as confirmed by infrared spectra. These complexes were then subjected to antibacterial studies using Gram-positive (Streptococcus pyogenes and Bacillus subtilis) and Gram-negative (Proteus vulgaris and Escherichia coli) organisms. The ligand and metal complexes exhibited pronounced antimicrobial activity against both types of bacteria. A docking study was conducted to evaluate the nature of the binding of the ligand and the most biologically active complexes to protein active sites of these bacteria. KEYWORDS antimicrobial activity and molecular docking studies, bis-Schiff base ligand, elemental and spectroscopic studies, thermal analyses, transition metal complexes

“…The minimum energy docked pose revealed that GFV ligand fitted into the curve contour of the targeted protein in the groove. Moreover, GFV ligand acted as strong hydrogen bond acceptor and was engaged in hydrogen‐bonding interactions with nitrogen atom of glycine amino acid (Figure c and Table ).…”

Section: Resultsmentioning

confidence: 99%

“…In order to incorporate the effect of solvent around the molecule, the time‐dependent DFT method (along with LANL2DZ basic set) was used to calculate the electronic absorption spectra of the ligand. The contributions of molecular orbital to highest occupied molecular orbital (HOMO) and lowest occupied molecular orbital (LUMO) were also calculated …”

Section: Methodsmentioning

confidence: 99%

Synthesis, characterization, density functional theory, X‐ray study, thermal stability, and biological and MOE relevance of metal complexes of griseofulvin

Mahmoud

2018

Self Cite

Metal(II) and metal(III) coordination compounds of griseofulvin (GFV) drug were synthesized. The structure of the ligand was determined on the basis of elemental analyses, infrared and 1 H NMR spectroscopies and thermal studies.GFV behaved as a neutral tridentate chelating agent and coordinated to metal ions through three oxygen atoms: two methoxy groups and oxygen atom of furan ring. Metal complexes were characterized by means of elemental analyses and molar conductance, spectral (infrared, electron spin resonance) and thermal studies. All the complexes showed molar conductance behaviour corresponding to an electrolytic nature. All the complexes showed octahedral geometry, except [Zn(GFV)Cl]Cl that showed tetrahedral geometry. Density functional theory (DFT) calculations were employed to understand and estimate the contribution of each interaction in the formation of the assembly using several theoretical models. The computed parameters from DFT calculations for structure optimizations and vibrational frequencies were in good agreement with the experimental data. Newly synthesized metal complexes in addition to GFV were examined against opportunistic pathogens. The biological applications of complexes were studied with two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and two Gram-negative bacteria (Escherichia coli and Neisseria gonorrhoeae) as well as their antifungal activity against Candida albicans. Results suggested that metal complexes were more biologically sensitive than free ligand. The complexes showed a moderate inhibition of MCF7 breast cancer cell line growth. Molecular docking studies further helped in understanding the mode of action of the compounds through their various interactions with the crystal structures of: human serum albumin (PDB: 5FUO), Staphylococcus aureus nucleoside (PDB: 3Q8U), human acetylcholinesterase (PDB: 1B41) and the human DNA-Topo I complex (PDB: 1SC7).