Synthesis, crystal structure and magnetic properties of a new tri‐nuclear iron (II, III) complex, a precursor for the preparation of superparamagnetic Fe 3 O 4 nanoparticles applicable in the removal of Cd 2+

This study reports the structural and spectroscopic characterization of a novel metal organic compound formulated as [Fe (bpy) 3 ] [Fe (dipic) 2 ] 2 .7H 2 O ( 1 ) (dipic = pyridine‐2,6‐dicarboxylate and bpy = 2,2 ′ ‐bipyridine). 1 was investigated by elemental analysis, FT‐IR spectroscopy, powder X‐ray diffraction and single crystal X‐ray diffraction (SC‐XRD), which revealed a triclinic structure of expected composition. Thermal degradation of 1 was also investigated. Complex 1 was used as a precursor to prepare superparamagnetic nanoparticles of Fe 3 O 4 by thermal analysis. The obtained Fe 3 O 4 was characterized by Fourier transformed infrared spectroscopy (FT‐IR), powder X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Fe 3 O 4 nanoparticles were used as a nano‐adsorbent to remove Cd 2+ from water at room temperature. The results showed that this nano‐adsorbent is effective in removing Cd 2+ from contaminated water sources, and that the maximal effectivity of adsorption occurs at pH = 6. Magnetic measurements of complex 1 and Fe 3 O 4 nanoparticles at room temperature revealed paramagnetic and superparamagnetic behavior, respectively.