Abstract: | Azatriquinane (=10-azatricyclo5.2.1.01,10]decane; 1 ) was oxidized to its radical cation 1 .+ by γ- irradiation in a CF2ClCFCl2 matrix at 77 K. A prominent feature of the ESR spectrum of 1 .+ is the 14N-hyperfine anisotropy which broadens the components with MI(14N)=±1. The observed coupling constants are aN=+ 2.5 and aH=+ 4.0 mT for the 14N nucleus and the three methine β-protons, respectively. While the aN value points to pyramidalization at the N-atom comparable to that in the radical cation of quinuclidine (=1-azabicyclo2.2.2]octane; 4 ), an eclipsing of the singly occupied orbital at this atom by the three C−Hβ bonds is indicated in view of the large aH value. Theoretical calculations on the geometry of 1 .+ are in accord with the conclusions drawn from the experimental findings. |