| Abstract: | The hitherto unknown radical cation of cyclobutene ( 2 ) has been generated in a CFCl3 matrix by γ rays at 77 K. The coupling constants, as determined from the ESR spectrum of 2 +, are 2.80 and 1.11 mT for the four CH2 and the two CH = protons, respectively. Photo-induced ring opening of 2 + yields a radical cation which exhibits the same ESR and ENDOR spectra as those observed upon direct ionization of s-trans-buta-1, 3-diene (s-trans -1 ). The radical cation s-trans -1 +, should, therefore, be the final product of this conversion. |
