INTERACTION OF WALSH-ORBITALS IN DIADEMANE AND RELATED HYDROCARBONS

To obtain further information concerning the interaction between Walsh-orbitals of 'conjugated' cyclopropane rings, the photoelectron spectra of the following compounds have been recorded: bicyclo[4.1.0]heptane 1, cis- and trans-tricyclo[5.1.03,5]octane 2, 3, diademane 4, transpentacyclo[3.3.2.02,9.04,10.06,8]decane 5 and bicyclo[4.1.0]heptene-2 6. The first bands in the PE.-spectra of these compounds have been assigned on the basis of a ZDO HMO-approximation. For 2 and 4 the value for resonance integral between linked 2p atomic orbitals of two adjacent eclipsed cyclopropane rings is found to be -1.73 eV.