Characterization of transient radicals in the reduction product of the –P
C
C
P– system: EPR and theoretical studies
Abstract
The C
C
P–Ar in THF exhibits hyperfine interaction (165 MHz) with two equivalent 31P nuclei. Additional couplings with two equivalent 13C are observed with Ar–P
13C
13C
P–Ar. The 31P anisotropic coupling constants could be obtained from
C
C
P–H]˙− and [H–P
CH–CH
P–H]˙−. Although the optimized geometries of these two species are clearly different, neither of them leads to 13C/31P hyperfine tensors in conflict with the experimental results. The absence of any 1H splitting on the EPR spectrum together with the quasi-reversibility of the reduction wave make the identification of [Ar–P
C
C
P–Ar]˙− more probable.