Structural characterization, spectroscopic studies, and molecular docking studies on metal complexes of new hexadentate cyclic peptide ligand

Abstract

New cyclic peptide ligand (L), 4,7,17,20‐tetrabenzyl‐2,5,8,16,19,22‐hexaoxo‐3,6,9,15,18,21‐hexaaza‐1(1,3)‐benzenacyclodocosaphane‐10‐carboxylic acid (BOABCA), was prepared using the recommended method. The ligand (L) and its complexes have been proven by using elemental analyses, molar conductivity, and magnetic moment measurements. The structural properties of the title compounds were explored using spectroscopy (1H NMR, ultraviolet [UV]–visible, and Fourier transform infrared [FT‐IR]) and mass spectrometry. The thermal decomposition of the ligand and its complexes are measured by thermal analysis (thermogravimetry [TG] and derivative thermogravimetry [DTG]) technique. The ligand (L) acts as neutral hexadentate with NNOOOO coordination sites and coordinating to the metal ions via the two nitrogen and four oxygen atoms. Bond lengths, bond angles, and quantum chemical characteristics have been established for the ligand and its complexes. The scanning electron microscope (SEM) analysis confirmed the presence of Fe(III) and Ni(II) complexes in nanostructure. The structural formula for the examined cyclic peptide ligand was optimized using Gaussian09 program. The energy gaps and other relevant theoretical parameters were computed applying the DFT/B3LYP technique. Antibacterial properties of the BOABCA ligand (L) and its transition metal complexes have been evaluated. In vitro biological properties for BOABCA ligand (L) and its transition metal complexes were carried out against Gram(+) bacteria (Bacillis subtilis and Staphylococcus aureus) and Gram(−) bacteria (Escherichia coli and Pseudomonas aeruginosa) employing agar diffusion method. The results showed that title compounds are biologically active than the parent BOABCA ligand. Molecular docking has shown favorable interaction between the title compounds and crystal structure of 3t88‐E. coli, 3ty7‐S. aureus, 5h67‐B. subtilis, and 5i39‐P. aeruginosa receptors.

Synthesis of new peptide-based macrocycles: Evaluation of their in vitro anti-proliferative activity and molecular dynamic simulation studies

“…Synthesis of m-phthaloyl-bis-[L-phenylalaninemethyl ester] and m-phthaloyl-bis-[Lphenylalanine], (3,4), respectively, were prebeared by Moustafa et al [16].…”

“…Therefore, synthesized proteins, serving as preliminary biological leads, enable the swift determination of molecular structural features associated with more potent drug principles. Consequently, an increasing number of both natural and synthetic peptides with noteworthy biological activities are being reported [16][17][18].…”

Computer modeling, docking, spectroscopic analysis, and antibacterial testing of metal chelates with dioxatetraaza ligand.

“…This shift can be assigned to the participation of etheric oxygen in the coordination. The shift in the v(NH) or towards lower or higher frequencies can be attributed to the change in the skeleton of the Schiff base ligand due to chelation to metal ions [29]. Additionally, the new bands between the areas of 417-470 cm-1, 511-540 cm-1 and 417-519 cm-1 can be attributed to v(M-N), v(M-O)etheric and v(M-O)water, respectively [30][31][32].…”

N′-((E)-3,3-Diphenyl-2,3-Dihydro-1H-Inden-1-Ylidene)-2-((Z)-2-Oxoindolin-3-Ylidene)Hydrazine-1-Carbothiohydrazide Ligand and Its Complexes: Spectroscopic, Molecular Orbital, Molecular Docking, Structural Study and Antimicrobial Activity

“…The ligands surface morphology is completely different from the surface morphology of metal complexes, which clearly shows the ligands binding to metal ions. [38].…”