| Abstract: | A method outlined previously 1] is used to show that in norbornadiene ( 3 ) the b 2(π) orbital lies above a 1(π), as predicted by theory. This indicates that in 3 through-space interaction between the two basis π-orbitals πa and πb is more important than through-bond interaction. Analysis of the PE.-spectra of 8-isopropylidene-tricyclo3.2.1.02,4]-octane ( 13 ) and the corresponding octene ( 15 ) confirms that the π-orbital πc of the exocyclic double bond conjugates more strongly with the symmetric Walsh-orbital e s of the cyclopropano moiety than with the π-orbital πa of a double bond in the same position. |
