ESR study of the structure and reactivity of spin-adducts of element- and metal-centered radicals with perfluorinated alpha-triketones

The addition of element-centered radicals to perfluorinated alpha-triketone s (CF3)(2)CFCOCOCOC2F5 (1) and (CF3)(2)CFCOCOCO(CF3)(2) (2) was studied by the ESR method, in the case of Si-centered radicals, alpha-siloxydiketometh yl radicals are formed, which are characterized by the highest delocalizati on of an unpaired electron. The dimerization of these radicals is character ized by a low value of the enthalpy of the radical-dimer equilibrium (2.7 k cal mol(-1)). The Ge-.(C6F5)(3) and Mn-.(CO)(5) radicals are added to 1 at the carbonyl group directly bound to the pentafluoroethyl substituent. The hindered rotation of the (CF3)(2)CF group was observed for the spin-adduct of Ge-.(C6F5)(3) with 2.