Synthesis, structural characterization, and DFT studies of new mixed-ligand iron(III) Schiff-base complexes

Cationic iron(III) Schiff-base aquo complex of the type [FeL(H2O)2]NO3 (L = C12H18N2O2) was accessed from the interaction of Fe(NO3)3 9H2O with the [N2O2] donor Schiff base. Reaction of the aquated complex with bifluoride [image omitted], thiocyanate (SCN-), or azide [image omitted] in 1 : 2 molar ratio in methanolic medium led to the synthesis of anionic mixed-ligand complexes, [FeLX2]n- (L = C12H18N2O2, X = F, NCS, N3). The tetradentate Schiff-base ligand was prepared from the condensation of acetylacetone and ethylenediamine following literature method and characterized by spectroscopic and single crystal X-ray diffraction technique. The complexes were characterized using elemental analysis, FT-IR, UV-Vis, mass spectroscopy, and solution electrical conductivity studies. The magnetic susceptibility measurements suggested high-spin Fe(III). The electronic structures of the compounds were analyzed by DFT method using B3LYP/6-31G(d,p) functional and overall, very good agreement between theoretical expectations and experimental data was achieved. The electrochemical behavior of the complexes was examined by cyclic voltammetric method.