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

The addition of element-centered radicals to perfluorinated α-triketones (CF3)2CFCOCOCOC2F5 (1) and (CF3)2CFCOCOCO(CF3)2 (2) was studied by the ESR method. In the case of Si-centered radicals, α-siloxydiketomethyl radicals are formed, which are characterized by the highest delocalization of an unpaired electron. The dimerization of these radicals is characterized by a low value of the enthalpy of the radical—dimer equilibrium (2.7 kcal mol−1). The Ge(C6F5)3 and ·Mn(CO)5 radicals are added to1 at the carbonyl group directly bound to the pentafluoroethyl substituent. The hindered rotation of the (CF3)2CF group was observed for the spin-adduct of ·Ge(C6F5)3 with2.