STRUCTURES OF SOME CYCLOALKANE MOLECULAR-IONS BY PHOTO-DISSOCIATION AND CHARGE-TRANSFER STUDIES IN AN ICR-SPECTROMETER

The photodissociation spectra of the molecular ions of some cycloalkanes are compared with those of the corresponding acyclic alkanes and alkenes. It is shown that the molecular ions of cyclohexane and cycloheptane are cyclic whereas the cyclopentane ring opens upon ionisation. This conclusion is supported by a study of the charge-transfer equilibria: C6D12± + C6H12 ⇌ C6D12 + C6H12±, C5D10± + C5H10 ⇌ C5D10 + C5H10±. It is furthermore shown that the maxima in the photodissociation spectra of the molecular ions of saturated hydrocarbons correspond to different dissociation processes. © 1979.