Synthesis, spectroscopic, electrochemical characterization, density functional theory (DFT), time dependent density functional theory (TD‐DFT), and antibacterial studies of some Co(II), Ni(II), and Cu(II) chelates of (E)‐4‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)‐1‐(3‐hydroxynaphthalen‐2‐yl)methylene) thiosemicarbazide Schiff base ligand

Abstract

In this study, mononuclear Co(II), Ni(II), and Cu(II) chelates of the potentially tridentate O, N, S donor ligand (E)-4-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-1-(3-hydroxynaphthalen-2-yl)methylene) thiosemicarbazide (H 2 L) were synthesized and characterized by elemental analyses, conductivity measurements, Fourier transform infrared spectroscopy, UV-visible spectroscopy, magnetic susceptibility, electron spin resonance (ESR) spectral analysis, thermal thermogravimetric analyses, cyclic voltammetry, and theoretical density functional theory (DFT) and time dependent density functional theory (TD-DFT) studies. The potential donors O (phenolic) and N (azomethine) are found in a syn configuration due to a strong intramolecular hydrogen bond [O-H …. N(1)] as shown in the 1 H NMR spectrum of the free ligand. In addition, analytical results revealed the formation of the metal chelates in a ligand-to-metal molar ratio of 1:1. The organic ligand (H 2 L) coordinated to the metal center through azomethine nitrogen, phenolate oxygen, and thione/thiolate sulfur groups with the formation of a five-and six-membered rings. The magnetic and spectral results supported the formation of tetrahedral geometry around the Co(II) and Ni(II) centers, while Cu(II) centers were assumed to have a square planar geometry. The time dependent density functional theory (TD-DFT) calculation outputs were used to expect and explain the experimental bathochromic and hypsochromic shifts resulting from the ligand chelation. The antibacterial activity of the compounds under study was evaluated in vitro against Staphylococcus aureus and Escherichia coli demonstrating Gram-positive and Gram-negative bacteria, respectively. It was found that among synthesized compounds, Cu(II) chelate 5 showed the most inhibitory activity against both Gram-positive and Gram-negative

Red emissive ternary europium complexes: synthesis, optical, and luminescence characteristics

“…The electronic band gap for Eu4 (3.201 eV) was found to be high in comparison with that for DD (2.989 eV). [ 44 ]…”

Insights into the Antimicrobial Activity of Hydrated Cobaltmolybdate Doped with Copper

“…The negatively charged surface groups (carboxyl or phosphate), which are present in the E. coli cell wall, can form bonds with the metal, released by the CoMoO 4 ·1.03H 2 O during the process called biosorption, destroying the integrity of the cell membrane and causing protein clotting [ 51 ]. It is also known that the coordination and redox chemical properties of cobalt can lead to its non-specific binding to various proteins, displacement of other metals (usually iron) from their natural binding sites, and the generation of free radicals [ 52 ].…”

“…In addition to the metal ion binding to biomolecules such as proteins, enzymes, and peptidoglycans present in the cell wall, El-Shaafaf et al [ 51 ] showed that metal can induce bacterial death by another route, in which it intercalates with phosphorus (compositional element is the teichoic acids that make up the cell wall of S. aureus ) elements in bacterial DNA, preventing the replication and expression of the ribosomal subunit protein and other cellular proteins. Consequently, the data that are presented in Table 5 in relation to the MIC of the analyzed systems infer that the metal performed this route more efficiently when they penetrated the cell wall of S. aureus .…”

New mononuclear Fe(III), Co(II), Ni(II), Cu(II), and Zn(II) complexes incorporating 4‐{[(2 hydroxyphenyl)imino]methyl}phenyl‐4‐methylbenzenesulfonate (HL): Synthesis, characterization, theoretical, anti‐inflammatory, and molecular docking investigation

“…The metal complexes were prepared according to the general procedure by mixing equal amounts (0.02 mol) [34][35][36][37] of hot ethanol solution of the ligand (HL) with the same ratio of metal salt (M:L = 1:1 molar ratio). The reaction mixture was refluxed under constant magnetic stirring for 12 h at 80 C. The resulting product was filtered and washed several times with ethanol.…”