Die ESR.‐Spektren der Radikal‐Anionen 1, 6‐überbrückter Cyclodecapentaene

The ESR.‐spectra of the radical anions of 1, 6‐methano‐cyclodecapentaene (II) and of 1, 6‐oxido‐cyclodecapentaene (VII), as well as of some of their deutero‐derivatives, are reported. The observed spin populations are in essential agreement with the predictions derived from a simple HMO‐model, if the electron repelling effect of the bridging groups is included. The reduced width of the spectra may be due to direct leakage of the unpaired electron into the CH‐σ‐orbitals, as a consequence of the breakdown of σ‐π‐orthogonality in the non‐planar π‐electron systems.