The asymmetric structure of the n-pentane radical cation: a theoretical study

An asymmetrically distorted structure of the n-pentane radical cation (trans–trans) has been located in B3LYP/6-311G(d,p) calculations, and it has a Cs symmetric geometry with one of the two central C–C bonds elongated. The B3LYP and CI calculations indicate that the Cs structure is lower in energy than the C2ν (2B2) structure. The calculated isotropic proton hyperfine coupling constants for the Cs and C2ν (2B2) structures are in fairly good agreement with the experimental couplings observed in an SF6 matrix and in an C6F14 matrix, respectively.