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

Abstract

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 [Cu2(L2)2(NO3)2] (1) and [Ni2(L2)2(CH3COO)2] (2) (L2 = 1‐(2‐{[(E)‐(4‐diethylamino‐2‐hydroxybenzylidene]amino} phenyl)ethanone oxime) were synthesized using HL1 and characterized by elemental analysis, spectroscopic methods, and single‐crystal X‐ray diffraction studies. It revealed that 1 had coordinated two nitrate ions whereas 2 had acetate ions. In the crystal structures, six‐coordinated Cu (II) complex 1 formed an infinite 2‐D and X‐shaped 3‐D supramolecular frameworks. Simultaneously, Ni (II) complex 2 assembled 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.