Phanes Derived from 1, 5- and 1, 7-Dihydro-s-indacene

Frontier orbital analysis of two conjugated, cyclic polyenes held face-to-face in close proximity suggests that when both polyenes have 4nπ-electron systems the interaction will be stabilizing, whereas when both have (4n+2)π-electron systems the interaction will be destabilizing[¹]. To test this prediction experimentally it would be of especial interest to examine phanes having nonbenzenoid aromatic and also antiaromatic decks as model compounds.