Cd(II)/Fe(III) heterobimetallic complexes with dien and cyanido ligands as precursors of ferrite-type oxides: Syntheses, crystal structures, thermal properties and identification of the oxides

Abstract

From the aqueous systems Cd(II) – dien – [Fe(CN)6]3-, where dien is 1,4,7-triazaheptane, two novel ionic complexes [Cd(dien)2]3[Fe(CN)6]2·3H2O (1) and NH4[Bu4N][Cd(dien)2]2[Fe(CN)6]2 (2) were prepared and characterized by spectroscopic (IR and UV–VIS) and EDX method. Both complexes 1 and 2 exhibit ionic crystal structures built up of [Cd(dien)2]2+ and [Fe(CN)6]3- complex ions; the respective crystals structures comprise water solvate molecules in 1 and, additional ammonium and tetrabutylammonium cations in 2. In both crystal structures the supramolecular structures are formed by extensive hydrogen bonding systems. The thermal decompositions of both complexes under dynamic conditions were studied on air. The solid residues 1R and 2R were identified by X-ray powder diffractometry as mixture of oxides formed of ferrite CdFe2O4 and CdO for 1R and iron hydroxide oxide, Fe1.833(OH)0.5O2.5 for 2R. Examination of the solid residues by SEM and EDX analyses has confirmed homogeneity of products, and for R2 discrete particles were observed.