ABSTRACT
Results obtained from CASSCF–MRMP2 calculations are used to explain the carbene products observed under matrix conditions for the interactions Fe(5D) + CH4–nFn (n = 2–4) in terms of two sequential reactions involving the radical species ·FeF + CH4–nFn–1. For the CH2F2 and CHF3 molecules, the first reaction leads to the radical fragments ·FeF + CH2F (or ·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 α-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.
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Acknowledgments
This research was supported by the Universidad Nacional Autónoma de México (DGAPA-PAPIIT). We would like to thank DGCTIC–UNAM for the use of the Miztli supercomputer. G. Castro gratefully acknowledges CONACYT for her graduate scholarship (288877).
Disclosure statement
No potential conflict of interest was reported by the authors.