Copper complexes of two cycloalkanespiro-5-dithiohydantoins: Synthesis, oxidation states and characterization

Synthesis of copper complexes with cyclopentanespiro-5-dithiohydantoin and cyclohexanespiro-5-dithiohydantoin is reported. Reaction conditions to stabilize Cu(II) oxidation state, which is known to be easily reduced by cyclic thiones, is described. Thus, Cu(II) and Cu(I) complexes were isolated in different reaction media starting from Cu(II) salts. The Cu(I) complexes were studied by means of solid-state 13C NMR and X-ray photoelectron spectroscopy (XPS), and the Cu(II) complexes were studied with EPR spectroscopy. In the latter case polymeric structure of the complexes is suggested, and dimeric structure for the Cu(I) complexes.