On the destabilization (strain) energy of biphenylene

Biphenylene is subject to a variety of destabilizing effects (antiaromaticity, ring strain) and resonance stabilization. Careful construction of a group equivalent reaction that isolates the destabilization energy from other chemical effects, notably resonance energy, leads to a revised estimate of the destabilization energy of biphenylene as 57 kcal mol-1. Extension of these ideas to higher homologoues of biphenylene, including starphenylene, point out pitfalls of any approach toward uniquely defining reactions that measure chemical effects.