Two two‐dimensional supramolecular copper(II) and cobalt(III) complexes derived from a new quinazoline‐type ligand: Syntheses, structures, and spectral, thermal, electrochemical and antimicrobial activity 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.

“…[61] Simultaneously, the negative values between HOMO and LUMO frontier orbitals manifested complexes were relatively stable. [62]…”

Section: Theoretical Investigationsmentioning

confidence: 99%

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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“…In previous work, several studies on the properties of copper (II) and cobalt (II) complexes have been reported. [19,20] As an continuation of our research, herein we mainly report synthetic routes (Scheme 1), characterization and biological activity of complexes [Zn (L) 2 (CH 3 OH) 2 ](NO 3 ) 2 (1) and [Ni(L) 3 ]Á(NO 3 ) 2 (2) with 2-(2-imidazolyl)-4-methyl-1,2-dihydroquinazoline-N 3 -oxide ligand (L). Zn (II) and Ni (II) complexes were characterized by X-ray crystallographic analysis and in both the metals show a six-coordination geometry.…”

Section: Introductionmentioning

confidence: 99%

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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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.

“…In terms of application, the complexes derived from these two different types of ligands have potential value in the fields of biochemistry, catalysis, luminescence, and so forth. [17] We continue our interest to study the coordination behavior and properties of transition metal complexes that are derived from some quinazoline-type ligands [18,19] ; as an extension of our investigations, in this paper we, explored two 3-D supramolecular cadmium (II) and nickel (II) 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 synthesized via complexation of cadmium nitrate tetrahydrate and nickel nitrate hexahydrate with the new quinazoline-type ligand L. X-ray crystallography indicated that both complexes emerged slightly distorted octahedral geometry with six-coordinated environment. It was worth noting that in the crystal structures of complexes 1 and 2, 1 assembled into an infinite 1-D chain-like, 2-D network and 3-D supramolecular skeletons, while 2 was presented infinite 1-D chain, fishnet-like 2-D and W-shape 3-D structures.…”

Section: Introductionmentioning

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

Zhang

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.