The photochemical metal organic deposition of manganese oxide films from films of manganese(II) 2-ethylhexanoate: a mechanistic study

Abstract

The photochemistry of thin films of manganese(II) 2-ethylhexanoate to produce manganese oxide films is presented. Thin films of manganese(II) 2-ethylhexanoate can be cast onto silicon wafers by spin coating. The FTIR spectroscopy of these films suggests they exist as chains or clusters with the manganese(II) centers linked by bridging 2-ethylhexanoate ligands. The initial photochemical reaction results in the loss of the bridging 2-ethylhexanoate ligands and the formation of monomeric manganese(II) 2-ethylhexanoate. In this process approximately 60% of the bridging 2-ethylhexanoate ligand is converted to chelating 2-ethylhexanoate while the other 40% fragments to form CO 2, heptane and heptene. Further photolysis resulted in the conversion of the remaining 2-ethylhexanoate ligand to form CO 2, heptane and heptene. The film consisted of manganese(II) oxide although the surface of the film was more oxidized and had carbon impurity on it. Annealing the film resulted in the conversion to polycrystalline α-Mn 2O 3.