Spectroscopic, crystal structural, theoretical and biological studies of phenylacetohydrazide Schiff base derivatives and their copper complexes

Two phenylacetohydrazide Schiff base derivatives: N’-(1-(2-hydroxyphenyl)ethylidene)-2-phenylacetohydrazide, HL1, and N’-((1-hydroxynaphthalen-2-yl)methylene)-2-phenylacetohydrazide, HL2, were synthesized. HL1 dimerizes in presence of HCl, probably via radical mechanism to give (2,2’-((1E)-hydrazine-1,2-diylidenebis(ethan-1-yl-1-ylidene))diphenol (DIM). Thermal reactions of Cu(II) ions with the two Schiff base ligands resulted in formation of the binuclear complexes [(CuL1)2] and [(CuL2)2]. The stoichiometry and structures of the reported compounds were investigated by several spectroscopic and analytical techniques. The structure of the HL1 ligand and its complex [(CuL1)2] as well as the DIM derivative were analyzed by single crystal X-ray analysis. The X-ray analysis revealed the binuclear coordination of the copper complex with the formation of five- and six-membered rings with every ligand. The molecular geometries of the ligands and their copper complexes were investigated using the DFT‐B3LYP/GENECP level of theory. The optimized structures of the studied complexes are consistent with the finding of the X-ray analysis. The quantum, non-quantum global reactivity descriptors and the non-linear optical properties were calculated. Biological studies including, antimicrobial and antioxidant activities of the complexes along with fluorescence quenching studies and viscosity measurements are carried out. The molecular docking of the two ligands and [(CuL2)2] complex is also reported. The different biological studies as well as molecular docking are correlated to each other and supported the fact that the complexes can bind to DNA via intercalative mode and showed a various DNA binding potency.peerReviewe

Synthesis, Antimicrobial Studies, and Molecular Docking Simulation of Novel Pyran, Pyrazole, and Pyranopyrazole Derivatives

A group of compounds containing pyran, pyrazole, and pyranopyrazole were synthesized (2–4) using a facile and convenient protocol. The structure of the synthesized compounds was elucidated by spectroscopic and elemental analysis. In vitro antimicrobial evaluation was also performed for all synthesized derivatives against human pathogenic bacterial strains such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis using chloramphenicol as a reference. It was depicted that compounds 3d, 4b displayed a high degree of inhibition against Bacillus subtilis and Staphylococcus aureus. Compounds 2d, 4f and 2d, 4e, 4f, and 4e had high inhibition effects against Escherichia coli and Pseudomonas aeruginosa, respectively. The molecular docking study was performed against S. aureus bacteria to rationalize the binding affinities and the feasible modes of interaction with the active site of tyrosyl-tRNA synthetase. It was found that the synthesized compounds were well fit into the binding site of tyrosyl-tRNA synthetase. The obtained results were in good accordance with the experimental data. The data obtained were promising candidates for further development of novel heterocyclic scaffolds as therapeutics with high efficacy biomedical precursors