CH₅⁺

Deborah Crittended, Keiran Thompson

We have recently developed the first chemically accurate PES for the CH5+ system, chemistry’s “Cheshire Cat”. This ion serves as the prototypical carbocation and its structure has been the subject of much controversy. The spectrum of CH₅⁺ has just been recorded, stimulating even more interest in the species. Our work was recently included in a feature article on CH₅⁺ in “Chemical & Engineering News”, the magazine of the American Chemical and Chemical Engineering Societies.

Two representations of the most probable configurations in the ground state of CH₅⁺ are displayed below.

We plan to extend our work to study how deuteration of CH₅⁺affects its structure, turning it from a “fluxional” to a “classical” molecule and we also plan to use our PES to provide a definitive value for the proton affinity of methane (and its deuterated analogues) and study how temperature affects structure. For the very ambitious student we would like to examine how nuclear spin statistics effect the properties of CH5+.

Selected Publications:

K. C. Thompson, D. L. Crittenden and M. J. T. Jordan “CH₅⁺: Chemistry’s Chameleon Unmasked” J. Am. Chem. Soc., 127, 4954-4958 (2005). pdf (186 kB)

CH5+

K. C. Thompson, D. L. Crittenden and M. J. T. Jordan “CH5+: Chemistry’s Chameleon Unmasked” J. Am. Chem. Soc., 127, 4954-4958 (2005). pdf (186 kB)

CH₅⁺

K. C. Thompson, D. L. Crittenden and M. J. T. Jordan “CH₅⁺: Chemistry’s Chameleon Unmasked” J. Am. Chem. Soc., 127, 4954-4958 (2005). pdf (186 kB)