Structural characterizations, spectroscopic, electrochemical properties, and antibacterial activities of copper (II) and cobalt (II) complexes containing imidazole ring

2022

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Two mono‐ and dinuclear Bi(III) complexes, [Bi(L)2(NO3)2]·NO3 (1) and [Bi2(L)2Cl8] (2) (L = (2‐(2‐pyridyl)‐4‐methyl‐1,2‐dihydroquinazoline‐N3‐oxide), were obtained via complexation of L with Bi(III) nitrate pentahydrate and Bi(III) chloride. L and both complexes were characterized by elemental analyses and spectroscopic methods including FT‐IR, UV–Vis, and fluorescence spectroscopy. Specifically, it clearly manifested that both complexes had good fluorescence emission and showed different fluorescence behaviors in diverse solvents. Both Bi(III) complexes were further determined by X‐ray crystallography, and it was found that the ratio of ligand to metal was 2:1 in 1, whereas 2 was 1:1. Their coordination geometric configurations were significantly different, such as octa‐coordinated complex 1 formed an infinite 1‐D chain‐like, funnel‐shaped 2‐D network, and ladder‐like 3‐D supramolecular framework, whereas hexa‐coordinated complex 2 with a binuclear structure exhibited two slightly distorted octahedral geometric structures; meanwhile, symmetric units came into being an infinite 2‐D layer even and meter‐shaped 3‐D supramolecular skeleton. The optimal geometries, frontier molecular orbital energies, and molecular electrostatic potential diagrams of both complexes were calculated using DFT/B3LYP. The electronic distribution of HOMO‐LUMO rationalized the results of UV–Vis spectra with the help of TD‐DFT calculations. Furthermore, all samples demonstrated excellent antibacterial activities against Escherichia coli and Staphylococcus aureus. In addition, non‐covalent interactions of complexes and their contributions were quantified with Hirshfeld surfaces using CrystalExplorer17 program.

Section: Uv-vis Absorption Spectra and Td-dft Calculationsmentioning

confidence: 99%

Two mono‐ and dinuclear Bi(III) complexes combined with crystallographic, spectroscopic, and antibacterial activities, MEP/HSA, and TD/DFT calculations

2022

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“…Both complexes demonstrated the optimum inhibitory effect against two bacterial strains at 2.5 mg ml À1 concentration, confirming that the bactericidal efficacy was usually concentration-dependent. [52,53] A possible interpretation for the discovered phenomenon in metal complexes was the chelation theory. During chelation, the metal ions in the complexes shared partially positive charges with donor atoms of the ligands, thus increasing the delocalization of π electrons on the whole chelating ring, which in turn enhanced the lipophilicity of the metal.…”

Section: Antimicrobial Activitymentioning

confidence: 99%

Antimicrobial activities of two 1‐D, 2‐D, and 3‐D mononuclear Mn (II) and dinuclear Bi (III) complexes: X‐ray structures, spectroscopic, electrostatic potential, Hirshfeld surface analysis, and time‐dependent/density functional theory studies

et al. 2022

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Two mononuclear and dinuclear octahedral complexes, [Mn(L1)2Cl2] (1) and [Bi2(L2)2Cl8] (2) (L1 = 2‐(2‐pyridyl)‐4‐methyl‐1,2‐dihydroquinazoline‐N3‐oxide, L2 = 2‐(3‐pyridyl)‐4‐methyl‐1,2‐dihydroquinazoline‐N3‐oxide) were prepared by natural volatilization method. The ligands and both complexes were compared with spectroscopic methods, as well as characterized by elemental analysis. The photoluminescence behaviors of both complexes in different solvents were also investigated. The coordination possibility of ligands toward Mn (II)/Bi (III) was verified using X‐ray crystallography, and it revealed that the ratio of ligand to metal was 2:1 in 1, whereas 1:1 in 2. The adjacent molecules of six‐coordinated complex 1 constituted an infinite 1‐D chain, 2‐D network, and ladder‐like 3‐D supramolecular frameworks. Most strikingly, hexa‐coordinated complex 2 with dinuclear structure formed an infinite 1‐D chain, 2‐D layered and meter‐shaped 3‐D supramolecular skeleton. Density functional theory (DFT) calculation was used to optimize the geometry of complexes, compute the electrostatic potential diagrams, and evaluate the HOMO‐LUMO energy gap. The electronic transition simulated through time‐dependent (TD)‐DFT level of calculation rationalized the experimental data. The antibacterial properties of all compounds were evaluated against Gram‐positive and Gram‐negative bacterial strains. In addition, the Hirshfeld surface was utilized to quantify some hydrogen bonding interactions and their contributions.

“…2-(2-Pyridyl)-4-methyl-1,2-dihydroquinazolin 3-oxide (L) was synthesized by modification of reported methods. [20] Yield 81.6%, m.p. 165-166 C. IR (KBr) ν/cm À1 : 3156 (N-H), 1611, 1490 (C=N), 1277 (N!O).…”

Section: Synthesis Of L Cd (Ii) and Ni (Ii) Complexesmentioning

confidence: 99%

Antimicrobial activities of cadmium (II) and nickel (II) complexes containing pyridine ring: Investigation of crystallographic, spectroscopic, Hirshfeld surface analysis, and TD/DFT calculations

et al. 2021

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Two complexes [Cd(L) 2 (NO 3 ) 2 ] (1) and [Ni(L) 2 (OH) 2 ][Ni(L) 2 (CH 3 OH) 2 ](NO 3 ) 2 ÁCH 3 OH (2) (L = 2-[2-pyridyl]-4-methyl-1,2-dihydroquinazolin 3-oxide) were gained via complexation an amount of the new ligand L with different nitrate salts. The obtained complexes were characterized by elemental analysis, spectroscopy, and X-ray crystallographic. In the crystal structure, centrosymmetric 1 adopted slightly distorted octahedral geometry. On the other hand, the independent unit of 2 contained two half Ni (II) complex located on a center of symmetry, differing for the axial ligand, two uncoordinated nitrate ions, and one lattice methanol molecule. Both the crystal structures formed a 3-D supramolecular architecture through different interactions (H-bonds, πÁÁÁπ, etc). X-ray crystallography revealed that complexes 1 and 2 had 2:1 ligandto-metal ratios. Most strikingly, 1 performed different fluorescence behaviors in diverse solvents, whereas 2 exhibited fluorescence quenching. When 1 was dissolution in N,N-dimethylformamide (DMF) solvent system, it has better fluorescence properties. The geometry optimization and HOMOs and LUMOs energies of both complexes were calculated by density functional theory (DFT) methods, and the nucleophilic and electrophilic attack sites were confirmed with electrostatic potential (ESP) calculations. Preliminary investigation of antimicrobial activities of all compounds against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Bacillus subtilis) was reported. Additionally, CrystalExplorer program was used to quantify the noncovalent interactions in complexes 1 and 2 through Hirshfeld surface analysis.