Synthesis, characterization and catalytic function of a B-12-hyperbranched polymer

A new hybrid catalyst composed of a vitamin B-12 derivative and a hyperbranched polymer (HBP) was synthesized and characterized by UV-vis and ESR spectroscopy as well as AFM. The B-12-HBP showed good properties as a homogenous catalyst. The covalently-immobilized B-12 moieties were efficiently solvated and the cobalt centers were accessible for pyridine guests. The B-12-HBP showed high reactivity to 2-phenethylbromide and increased selectivity for reductive dimerization in the presence of TiO2 with UV light irradiation.