[Co(en)3][Fe(CN)6] · H2O and [Co(en)3][Fe(CN)6]: A dehydration process investigated by single crystal X-ray analysis, thermal analysis and Mössbauer spectroscopy

The complexes [Co(en)3][Fe(CN)6] · H2O (1) and [Co(en)3][Fe(CN)6] (2) (en = 1,2-diaminoethane) have been prepared and characterized by elemental analysis, single crystal X-ray analysis, TG/DSC analyses and 57Fe Mössbauer spectroscopy. Single crystals of 1 have been prepared by recrystallization of compound 1 from a water solution, while crystals of complex 2 have been synthesized in the solid state by dynamic heating of 1 up to 150 °C. Both complexes exhibit ionic structures built up of [Co(en)3]3+ cations and [Fe(CN)6]3− anions. The presence and/or absence of the crystal water molecule in the complexes has a strong influence on their thermal stability, the extent of hydrogen bonding in the crystal structures and on the symmetry of the iron(III) environments in the [Fe(CN)6]3− anions, as determined by 57Fe Mössbauer spectroscopy.

Single crystals of [Co(en)3][Fe(CN)6] · H2O (1) have been transformed to an anhydrous complex of [Co(en)3][Fe(CN)6] (2) by dynamic heating of (1) up to 150 °C in the solid state. X-ray structures have been determined in both cases.Figure optionsDownload as PowerPoint slide