Synthesis, Structure, and Properties of New Hybrid Nanocomposites Containing the [Mo_6(μ_3-Cl)_8]~(4+) Cluster

摘要

A new type of hybrid nanocomposite material is produced via consecutive outer-sphere transformations of a Mo-containing cluster. Cluster monomers with the general formula (Bu_4N)_2[(Mo_6Cl_8)(CF_3COO)_(6-n)CH_2 =CHCOO_n] (n = 1-3) are synthesized and characterized for the first time. The bulk radical copolymerization of such monomers with acrylic acid is an interfacial process and leads to the formation of hybrid (metal-containing polymeric) nanocomposites. The synthesized copolymers (approx = 1-5 wt % Mo, M_η approx = 270000, 5-24 cluster units per polymer chain) are examined by nuclear magnetic resonance and IR spectroscopy. The results indicate that the copolymers contain stereoregular (syndiotactic) polyacrylic acid. The structure of the cluster-containing composites, the distribution of cluster units over the polymer chain, and the origin of stereoregularity in such systems are discussed. According to differential thermal analysis results, the introduction of clusters into the polymer chain has an insignificant effect on the thermal stability of the nanocomposites. The same is evidenced by the results on the molecular-topological properties of the nanocomposites.