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

The quinazoline-type ligand 2-(4-diethylamino-2-hydroxyphenyl)-4-methyl-1,2-dihydroquinazoline 3-oxide (HL1; H is the deprotonatable hydrogen) was prepared. Two 2-D supramolecular complexes [Cu-2(L-2)(2)(NO3)(2)] (1) and [Ni-2(L-2)(2)(CH3COO)(2)] (2) (L-2= 1-(2-{[(E)-(4-diethylamino-2-hydroxybenzylidene]amino} phenyl)ethanone oxime) were synthesized usingHL(1)and characterized by elemental analysis, spectroscopic methods, and single-crystal X-ray diffraction studies. It revealed that1had coordinated two nitrate ions whereas2had acetate ions. In the crystal structures, six-coordinated Cu (II) complex1formed an infinite 2-D and X-shaped 3-D supramolecular frameworks. Simultaneously, Ni (II) complex2assembled into wavy 2-D networks. Furthermore, electrochemical properties and antimicrobial activities of all compounds were as well investigated. Afterwards, the electrophilic and nucleophilic attack sites identified by electrostatic potential (ESP) calculations confirmed that hydrogen bonds were observed in the optimized structure of the crystal, and the closest contact between the active atoms of both complexes was confirmed through Hirshfeld surface analysis and time-dependent density functional theory (TD-DFT) calculations.

Automated summary

Two quinazoline-type ligand metal complexes were synthesized and characterized, with each coordinating different anions and forming distinct supramolecular structures. Additionally, the electrochemical properties and antimicrobial activities of all compounds were investigated.