Two dinuclear copper (II) and nickel (II) complexes based on 4‐(diethylamino)salicylaldehyde: X‐ray structures, spectroscopic, electrochemical, antibacterial, Hirshfeld surfaces analyses, and time‐dependent density functional theory calculations

et al. 2022

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Two complexes [Zn(L) 2 (CH 3 OH) 2 ](NO 3 ) 2 (1) and [Ni(L) 3 ]Á(NO 3 ) 2 (2) (L = 2-[2-imidazolyl]-4-methyl-1,2-dihydroquinazoline-N 3 -oxide) were obtained successfully by means of slow evaporation solution technique (SEST)and characterized using elemental analysis, FT-IR, UV-vis, and fluorescence spectroscopic. X-ray diffraction revealed that the metal in complex 1 is chelated by two L ligands and two lattice methanol molecules, whereas in 2 by three L ligands, counterbalanced by nitrate ions. The crystal structures of both showed infinite 1-D, 2-D, and 3-D supramolecular architecture due to intermolecular interactions. Most strikingly, Zn (II) complex showed different fluorescence properties in diverse solvents. The antimicrobial activities of all compounds were compared and showed perceptible efficiency against Gramnegative and Gram-positive bacteria. Electrostatic potential (ESP) calculation was used to predict the nucleophilic and electrophilic attack sites. Density functional theory (DFT) calculation results showed good agreement with experimental data, as well as the frontier molecular orbital energy gaps were detected by time-dependent (TD)-DFT method with HOMO-LUMO calculations. Additionally, the non-covalent interactions of both complexes were further quantified and explored with the help of Hirshfeld surface analysis.

Section: Charge Distribution and Espsupporting

confidence: 86%

Novel zinc (II) and nickel (II) complexes of a quinazoline‐based ligand with an imidazole ring: Synthesis, spectroscopic property, antibacterial activities, time‐dependent density functional theory calculations and Hirshfeld surface analysis

et al. 2022

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“…From the ESP figure, it was observed that negative regions (red spheres) were distributed over the nitrogen atom of the imidazole ring or nitrate, while the positive regions (blue spheres) were mainly localized the H-atoms. [66] These theoretical consequences were in well keeping with the experimental values of X-ray diffraction. Hence, the electrophilic and nucleophilic attack sites were determined using ESP calculations; it was verified that hydrogen bonds were aware in the optimized structure of the crystal.…”

Section: Charge Distribution and Electrostatic Potentialsupporting

confidence: 73%

Co (II) and Cd (II) complexes with imidazole‐2‐carboxaldehyde groups: spectroscopic, antibacterial, Hirshfeld surfaces analyses, and TD/DFT calculations

et al. 2021

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Two complexes [Co(L) 2 Á2CH 3 OH] 2 Á(NO 3 ) 4 (1) and [Cd(L) 2 (NO 3 ) 2 ] (2) (L = 2-(2-imidazolyl)-4-methyl-1,2-dihydroquinazoline-3-oxide) were synthesized by natural evaporation of Co (II)/Cd (II) nitrate with a new heterocyclic ligand. The metal complexes are characterized by elemental analysis, spectroscopy, and X-ray crystallographic. In the crystal structures, Co (II) complex 1 was in a six-coordinated coordination environment and constituted an infinite 1-D chain, 2-D network, Meter-shaped 3-D supramolecular framework, while Cd (II) complex 2 assembled into an infinite 1-D, wave-like 2-D, and dragonfly-shaped 3-D skeleton. Specifically, nitrate ions were present as a dissociated group in complex 1, whereas complex 2 was involved in the coordination. Moreover, Cd (II) complex exhibited different fluorescence behaviors in diverse solvents. Remarkably, all the compounds have shown perceptible antibacterial activity against Gram-positive and Gram-negative bacteria. Furthermore, the electrostatic potential (ESP) calculations were utilized to analyze electrophilic and nucleophilic attack sites on the molecule, which verified the existence of hydrogen bonds in the optimized crystal structure. In addition, the structural features of metal complexes have been remarkably rationalized, and the overall trends obtained in the experimental values have been resoundingly remade by TD/DFT calculations. The detailed Hirshfeld surface analysis and fingerprint plots yielded a comparative picture of the mode of non-covalent interactions.

“…These characteristics were in good agreement with the quasiinvertibility of similar complexes in the refences. [52] 3.5 | Electron paramagnetic resonance spectroscopy EPR spectra of samples 1 and 2 were measured at 300 K. As shown in Figure 9 (2.241 or 2.049) > g e (2.0023) indicated that the paramagnetic centers of octahedron, square plane and pyramid geometry were axisymmetric, and single unpaired electron of Cu (II) ion was located at d(x 2 À y 2 ) ground state. The g k value was regarded as a momentous parameter for the covalent properties of the metal-ligand bond.…”

Section: Electrochemistry Studiesmentioning

confidence: 98%

Two mono‐ and dinuclear Cu (II) complexes derived from 3‐ethoxy salicylaldehyde: X‐ray structures, spectroscopic, electrochemical, antibacterial activities, Hirshfeld surfaces analyses, and time‐dependent density functional theory studies

et al. 2021

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The quinazoline-type ligand 2-(3-ethoxy-2-hydroxyphenyl)-4-methyl-1,-2-dihydroquinazolin 3-oxide (HL 1 , H is the deprotonatable hydrogen) was synthesized. Two mono-and dinuclear Cu (II) complexes, [Cu(L 2 ) 2 ]Á2CH 3 OH (1),amino}phenyl)ethanone oxime), were obtained via complexation of HL 1 with Cu (II) acetate monohydrate or Cu (II) nitrate trihydrate in methanol. HL 1 and both complexes were characterized by elemental analyses and spectroscopic methods. The structures of complexes were confirmed by single-crystal X-ray crystallography and the ratio of ligand to metal in 1 was 2:1 whereas 2 was 1:1. In the crystal structures, hexa-coordinated Cu (II) complex 1 was assembled into an infinite 1-D, 2-D network and 3-D supramolecular framework. Complex 2 included four deprotonated (L 2 ) À units, four coordinated Cu (II) and two coordinated nitrate anions, forming an infinite 2-D layer and interesting butterfly-shaped 3-D supramolecular skeleton. Specifically, the Cu1 and Cu4 centers were four-coordinated, while the Cu2 and Cu3 centers were penta-coordinated in 2. Furthermore, electrochemical properties and antibacterial activities of both complexes were also investigated. In addition, the electron paramagnetic resonance (EPR) spectra of 1 and 2 were also studied. The optimal geometries, HOMO-LUMO energies and molecular electrostatic potential diagrams of two complexes were calculated using density functional theory (DFT)/B3LYP, and specific electronic transitions in the UVvis spectra of 1 and 2 were recorded by time-dependent DFT (TD-DFT) calculations. Additionally, the noncovalent interactions between both complexes were also confirmed by Hirshfeld surfaces.