Cyclopropane Jahn-Teller distortion

The cyclopropane radical cation can be prepared by y-radiolysis in rigid matrices. At temperatures as low as 4.2 K, its ESR spectrum shows evidence for static Jahn-Teller distortion, resulting in a structure of the (ring-closed) trimethylene ( Ai) type, r " ... 

The cyclopropane radical cation can be prepared by y-radiolysis in rigid matrices its ESR spectrum at 4.2 K shows evidence for static Jahn-Teller distortion, resulting in a structure of the trimethylene (2Aj) type [294, 295], Irradiation of several methyl substituted derivatives at 77 K gave rise to a family of radical cations of the same structure type [293], which had been previously identified on the basis of CIDNP results [229, 230]. We begin with a discussion of the CIDNP investigations, since they preceded the ESR studies of all species but the prototype. 

As can be seen from Figure 17, the shapes of bands and are strongly influenced by the Jahn-Teller effect, i.e. by the distortion of the cyclopropane radical cation in its electronic ground state E and its first excited state E". For a discussion of this effect the reader is referred to work by Haselbach . 

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