Intramolecular dimer radical anions of [3n] cyclophanes: transannular distance dependent stabilization energy

Abstract

Intramolecular dimer radical anions of [3_n]cyclophanes generated by γ-ray irradiation in low-temperature glassy matrices showed an absorption band attributable to charge resonance around 936–1210 nm, from which the stabilization energy of the dimer radical anions were analyzed on the basis of π-electron delocalization over two benzene rings and the damping factor (β) was estimated to be 0.35 Å⁻¹, which is smaller than that of the intramolecular dimer radical cation of [3_n]cyclophanes, indicating a effective charge delocalization of the dimer radical anions.