Synthesis, structural characterization, DNA cleavage studies, antimicrobial activities, and time‐killing kinetics of tetranuclear Cu (II) with partial cubane Cu₄O₄ cores and mononuclear Co (II) and Ni (II) complexes of a new acylhydrazone ligand

Abstract

In the present study, a new acyl hydrazone N 0 -(3-ethoxy-2-hydroxybenzylidene)isobutyrohydrazide (ehbbhH 2 ) and its metal complexes(2), and [Cu 4 (ehbbh) 4 ]Á4H 2 O (3) were prepared. The structure of the ligand was characterized using elemental analysis, GC-MS, electronic, IR, 1 H, and 13 C NMR spectra. The structure of the prepared complexes was investigated by spectral, analytical, thermal, and magnetic susceptibility measurements. The results revealed that complexes 1 and 2 were formed in a 1 M:2 L mole ratio, whereas Complex 3 was formed in a 1:1 mole ratio. Spectral studies showed that the ligand in complexes 1 and 2 bonded to the metal ion in a monoanionic tridentate fashion through the azomethine nitrogen atom, carbonyl, and phenolic oxygen atoms. In Complex 3, ligand acted as dianionic tetradentate through the azomethine nitrogen atom, enolic, phenolic, and ethoxy oxygen atoms. The molecular structures of the ligand and Complex 3 were also established using single-crystal X-ray diffraction. The X-ray structures of Complex 3 revealed that they contained a distorted Cu 4 O 4 cubane core. The present study investigated the cleavage activities of the ligand and its complexes on supercoiled pBR322 DNA. Complex 3 was determined to be the most effective compound on pBR322 plasmid DNA in the presence of hydrogen peroxide. The antimicrobial activities of all compounds were investigated against two Gram-positive bacteria, two Gram-negative bacteria, and one eukaryote. The results showed that Complex 3 exhibited better antimicrobial activity than other complexes. Finally, time-killing assays of Complex 3, which was the most effective complex, were carried out.

Synthesis, Characterization, Antimicrobial and Time Killing Activities of New Sulfa-Derived Schiff Bases Coordinated with Cu(II)

“…However, the increasing resistance of microorganisms to chemotherapeutics has made it necessary to synthesize new chemicals. Studies on the synthesis of new complexes and the acquisition of new antimicrobials in the laboratory environment have gained importance in recent years, and quite a lot of new studies are being done on this subject [33][34][35][36][37][38][39]. It is known that sulfonamides are the oldest and most well-known antimicrobial agents widely used against bacterial and fungal infections.…”