Two Novel Unsymmetrical Ferrocene Based Azines and Their Complexing Abilities Towards Cu(II): Spectroscopy, Crystal Structure, Electrochemistry and DFT Calculations

Abstract

Two new ferrocenyl-substituted unsymmetric azine ligands and their Cu(II) complexes were prepared. The redox active ferrocene-based azine ligands 1 and 2 were obtained by the condensation of 1-[(E)-hydrazinylidenemethyl]naphthalen-2-ol and 2-[(E)-hydrazinylidenemethyl]-4-nitrophenol with ferrocenecarboxaldehyde, respectively. The structures of the ligands and their Cu(II) complexes were characterized by IR, UV-Vis, NMR, X-ray, magnetic measurements and TG techniques. The 2-[(E)-hydraz-inylidenemethyl]-4-nitrophenol derivative azine ligand (2) was found to be rearranged by the Cu(II) ion without water or acid/base catalyst. The redox behaviors of the ferrocene derivative compounds were investigated by cyclic voltammetry. Structural parameters and spectroscopic properties of the azine ligands (1 and 2) and the Cu(II) complex (1a) were calculated using DFT and TD-DFT/CPCM methods and the results were compared with the experimental data. © 2015 Elsevier Ltd. All rights reserved.