Oxidation of a three-dimensional polymeric iron(II) complex with sodium nitrite in acidic medium

Oxidation of the water-insoluble polymeric iron(II) complex, (Me₃Sn)₄Fe^II(CN)₆] _n , with NaNO₂ in an acidic medium was followed by monitoring the increase of absorbance of the water-soluble polymeric iron(III) complex product at 419 nm. The reaction is first order in polymer, oxidant and ethanoic acid. Experiments over the temperature range 25–40 °C allowed calculation of the activation parameters. The reaction between the solid polymeric iron(II) complex and NO₂ has been investigated by i.r., electronic-reflectance, X-ray powder diffraction spectra and magnetic measurements. A mechanism involving electron-transfer is proposed.