Partly Olefinic Reference Structure Defined to Evaluate Bond Resonance Energy and the Ring Current It Would Sustain*

The concept of bond resonance energy (BRE) is useful for estimating the degree of kinetic sta-bility for a variety of polycyclic -systems. In evaluating the BRE for a given bond in a polycyclic -system, the corresponding partly olefinic reference structure has been defined, in which cyclic conjugation via the bond is forbidden. The ring-current pattern expected for such a hypothetical -system were estimated graph-theoretically. Such a ring-current pattern proved very useful to visualizing and characterizing the mode of cyclic conjugation in a partly olefinic -system. Key words bond resonance energy ring current partly olefinic -system -system * Dedicated to Professor Nenad Trinajsti} on the occasion of his 65th birthday