Summary. The key findings of the present investigation are (a) that significant through-space methyl-? r interactions exist in the+'* and G4* negative ion states of 4 and 5,(b) the this interaction in fi4*, and probably also in &*, primarily involves the hydrogen 1s (T) rather than the carbon p (~) orbital of the methyl group, and (c) that conformations with interior out-of- plane methyl hydrogens make a significant (but as yet unspecified) contribution to the ...
