Copper(II) Nanoballs as monomers for polyurethane coatings: synthesis, urethane derivatization and kinetic stability

The self-assembly of copper(II) ions and 5-(2-hydroxyethoxy)benzene-1,3-dicarboxylate (1) leads to Nanoballs in which twelve dinuclear copper(II) paddle-wheel units are interconnected via 24 ligands. The structure of the spherical coordination compound decorated with 24 hydroxy groups has been determined by single crystal X-ray structure analysis. As a model for the integration of Nanoballs into bulk polyurethane polymers and coatings, its reaction with phenylisocyanate is investigated. The stability of Nanoballs against hydrolytic decomposition is studied under acidic conditions and compared to simple copper(II) complexes. Release of copper(II) ions from Nanoballs is much slower than from discrete copper(II) paddle-wheel complexes, suggesting the use of Nanoballs as monomers for polyurethane-based antifouling coatings.