Charge-Segregated Ion-Pairing Assemblies Comprising Dipolar π-Electronic Cations

Two pentamethine dyes with nearly identical structures but slightly different dipole moments were prepared as ion pairs. The ion pairs provided charge-segregated assemblies stabilized by dipole-dipole interactions between the positively charged π-electronic systems. The stacking structure of the bromo-substituted pentamethine cation was more stabilized by a larger dipole moment, as suggested by energy decomposition analysis. Depending on the packing arrangements, highly electric conductive properties were observed owing to charge-segregated structures, as also correlated with the theoretically estimated transfer integrals.