Use of a two-sequential radical reaction scheme to rationalise the high-oxidation-state carbene species detected under confinement conditions for the interactions Fe(D-5) + CH4-&ITn&ITF&ITn&IT (&ITn&IT = 2-4)

摘要

Results obtained from CASSCF-MRIVIP2 calculations are used to explain the carbene products observed under matrix conditions for the interactions Fe(D-5) + CH4-nFn (n = 2-4) in terms of two sequential reactions involving the radical species center dot FeF + CH4-nFn-1. For the CH2F2 and CHF3 molecules, the first reaction leads to the radical fragments center dot FeF + CH2F (or center dot CHF2). As these species remain trapped in the matrix, they can recombine themselves to form the inserted complex CH2F-Fe-F (or CHF2-Fe-F). The carbene H2C = FeF2 (or HFC = FeF2) is reached from the inserted structure by alpha-migration of an additional fluorine atom to the metal centre. The rebounding reactions can take place along both the quintuplet and triplet asymptotes varying only in the spin of the non-metal fragment. This model explains the triplet compound H2C = FeF2 detected for the interaction Fe + CH2F2 and allows theoretically assigning as quintuplet the complex HFC = FeF2 observed for the reaction Fe + CHF3.& para;& para;