Studies on Radical Cations I. Molecular and electronic structure of [3]radialene cation produced by γ‐irradiation in condensed phase

Abstract γ‐Irradiation of tris (methylidene)‐cyclopropane (‘[3]radialene’) 1 in a rigid electron scavenging matrix (butylchoride/i‐pentane, 1:1) at 77 K leads to formation of its molecular cation 1+. Slight softening of the matrix by a temperature increase of 3–5 K results in formation of a newly absorbing species, tentatively assigned arising from structrral relaxation of 1+ by π‐bond rotation: magnified image