Preparation of manganese(II), chromium(III) and ferric(III) oxides nanoparticles in situ metal citraconate complexes frameworks

• Citaraconate frameworks.
• Preparation of oxides nanoparticles.
• Carboxylic groups are bidentatically bridging and chelating.
• Oxocarbonates form was formed as intermediate.

The new reactions of some divalent and trivalent transition metal ions (Mn(II), Cr(III), and Fe(III)) with citraconic acid has been studied. The obtained results indicate the formation of citraconic acid compounds with molar ratio of metal to citraconic acid of 2:2 or 2:3 with general formulas Mn2(C5H4O4)2 or M2(C5H4O4)3⋅nH2O where n = 6 for Cr, and Fe(III). The thermal decomposition of the crystalline solid complexes was investigated. The IR spectra of citraconate suggested that the carboxylic groups are bidentatically bridging and chelating. In the course of decomposition the complexes are dehydrated and then decompose either directly to oxides in only one step or with intermediate formation of oxocarbonates. This proposal dealing the preparation of MnO2, Fe2O3 and Cr2O3 nanoparticles. The crystalline structure of oxide products were checked by X-ray powder diffraction (XRD), and the morphology of particles by scanning electron microscopy (SEM).

SEM image of the final thermal decomposition products of (A): manganese(II), (B): ferric(III) and (C): chromium(III) citraconate compounds obtained at 500 °C.Figure optionsDownload as PowerPoint slide