The solid‐state decomposition and oxidation of dicobaltoctacarbonyl in a polymer matrix

The decomposition of Co₂(CO)₈ in hydrocarbon solutions, to Co₄(CO)₁₂ and further to metallic Co and carbon monoxide under an inert atmosphere, has been extensively studied and is well documented in the literature. We report here a study of the solid‐state decomposition of Co₂(CO)₈ in a polymeric matrix under various conditions. Co₂(CO)₈ was incorporated into polystyrene by film casting from CH₂Cl₂ solutions under CO at room temperature. These films were decomposed at 90°C under N₂. The decomposition rate of the Co₂(CO)₈ in polystyrene films was two orders of magnitude slower than for hydrocarbon solution decompositions. Conversely, the oxidation of Co₂(CO)₈ to CoO or Co₂O₃ in air at room temperature was observed to be two orders of magnitude faster in the polystyrene matrix as compared with solutions. When protective layers of polystyrene were cast on both sides of the Co₂(CO)₈‐polystyrene films, oxidation became slower as a function of the thickness of the protective polymer layers. These observations, supported by infrared spectra, TEM micrographs, and electron diffraction patterns, are discussed to compare the solution and solid‐state chemistry of Co₂(CO)₈.