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

Abstract

SynopsisThe decompasition of Cq(CO), in hydrocarbon solutions, to Co,(CO),, 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 Ca,(CO), in a polymeric matrix under various conditions. Co,(CO), was incorporated into polystyrene by film casting from CH,CI, solutions under CO a t room temperature. These films were decomposed a t 90°C under N,. The decomposition rate of the Ca2(CO), in polystyrene f i l m s was two orders of magnitude slower than for hydrocarbon solution decompositions.Conversely, the oxidation of Cq(CO), to COO or C%O, in air a t 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 Cq?(CO),-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 Co,(CO),.

Magnetic Hydrogels from Alkyne/Cobalt Carbonyl-Functionalized ABA Triblock Copolymers

“…x Composites. Heating of cobalt carbonyl precursors within a polymer or block copolymer matrix at moderate temperatures (90−200 °C) has previously been reported to result in decomposition of cobalt carbonyl complexes 69,70 and generation of cobalt nanoparticles. 7,57,71 With PPES-b-polystyrene block copolymers, the formation of cobalt nanoparticles has been observed to be restricted to the PPES regions.…”

“…Heating of cobalt carbonyl precursors within a polymer or block copolymer matrix at moderate temperatures (90–200 °C) has previously been reported to result in decomposition of cobalt carbonyl complexes , and generation of cobalt nanoparticles. ,, With PPES- b -polystyrene block copolymers, the formation of cobalt nanoparticles has been observed to be restricted to the PPES regions . Initial attempts at heating freshly prepared PES n [Co 2 (CO) 6 ] x -EO 800 -PES n [Co 2 (CO) 6 ] x samples at 120 °C for 24 h under a vacuum resulted in disruption of the initial morphologies, as evidenced by TEM (Figure S17).…”

Large-scale synthesis of defined cobalt nanoparticles and magnetic metal–polymer composites

“…In fact, especially in the preparation of nanocomposites, the cobalt particles have mostly been synthesized only in situ. For this purpose dicobaltoctacarbonyl was decomposed in the presence of a dissolved polymer, [14][15][16][17][18][19] which stabilized the emerging cobalt particles, a strategy which was also transferred to the preparation of nanocomposites with iron or iron oxide by decomposing iron pentacarbonyl (Fe(CO) 5 ). [20][21][22] However, in those routes the average particle size depends strongly on the applied polymer and the metal content in the reaction system, which complicates the preparation of defined composites.…”

Preparation and magnetic resonance imaging effect of polyvinylpyrrolidone‐coated iron oxide nanoparticles

“…In this study, PVP‐coated iron oxide nanoparticles were prepared by thermal decomposition of Fe(CO) 5 , organometallic complexes, in the presence of PVP used as a stabilizer based on the preparation presented previously 8–15. They were characterized from the view points of size distribution and stability in the aqueous media, and their application as a MRI contrast agent of focal liver lesions.…”