Investigation of the solid state reaction of FeSO4·7H2O with 1,10-phenanthroline

Abstract

Solid-state reaction of FeSO4·7H2O and 1,10-phenanthroline in a 1 ∶ 1 molar ratio was investigated by time-resolved in-situ energy dispersive X-ray diffraction (EDXRD), DSC, TG/DTA, Mossbauer and IR spectroscopy. The reaction of these solids takes place rapidly at around 70 °C and initially produces an intermediate crystalline phase, Fe(phen)3SO4·5H2O before cleanly converting to Fe(phen)(H2O)3SO4. This is in contrast to the product of the reaction of FeSO4·7H2O with 1,10-phenanthroline in aqueous solution which produces [Fe(phen)32+][SO42−]. All the spectral data suggest that the final product is a neutral Fe(II) complex. The coordination sphere around the Fe(II) ions is thought to be octahedral consisting of a unidentate sulfate ligand, a bidentate 1,10-phenanthroline ligand and three aquo ligands.