Evaluation of beta Value of Phenylene Unit by Probing Exchange Interaction between Two Nitroxides

Abstract

Oligophenylene molecular rods with bicyclo[2.2.2]octane having two nitronyl nitroxide radicals were synthesized to investigate the decay constant of p-phenylene. By the measurement and simulation of the ESR spectra of the biradicals with different rod length, it was found that the exchange interaction was decreased with the decay constant beta of 0.51 A^-1. This result indicates that the spin-spin exchange interaction between neutral radicals has a similar decay constant to the molecular conductance.