Synthesis, X-ray structure, spectroscopic, electrochemical properties and DFT calculation of a bridged dinuclear copper(II) complex

A bridged dinuclear Schiff base-type copper(II) complex, [(Cu-2(L-2)(2)CH3COO)](2)[ Cu(NO3)(4)]center dot 2CH(3)COOCH(2)CH(3) (HL2 = 1-(2-{[(E)-3,5-dibromo-2-hydroxybenzylidene] amino} phenyl) ethanone oxime), has been synthesized via complexation of Cu(II) nitrate trihydrate with HL1 (2-(3,5-dibromo-2-hydroxyphenyl)-4-methyl-1,2-dihydroquinazoline-3-oxide, H is the deprotonatable hydrogen). During the reaction, the C-N bond in the HL1 is converted into the C=N-OH group in the ligand HL2. The Cu(II) complex was analyzed using IR and UV-Vis spectroscopy, elemental analysis and single-crystal X-ray crystallography. The spectroscopic data of the Cu(II) complex was compared with the ligand HL1. In the crystal, each complex links with four other molecules into an infinite 2-D supramolecular structure through intermolecular hydrogen bonding and pi...pi stacking interactions. Moreover, the electrochemical properties of HL1 and Cu(II) complex have been studied by cyclic voltammetry. The powder EPR spectrun of the dinuclear Cu(II) complex indicated that the existence of an antiferromagnetic spin-spin interaction between the magnetically nonequivalent two Cu(II) ions. The geometries and electronic properties of both the ligand HL1 and the Cu(II) complex were studied by DFT calculation. (C) 2016 Elsevier B.V. All rights reserved.