Delocalization of Positive Charge in pi-Stacked Multi-benzene Rings in Multilayered Cyclophanes

作者：Fujitsuka Mamoru; Tojo Sachiko; Shibahara Masahiko; Watanabe Motonori; Shinmyozu Teruo; Majima Tetsuro^*

来源：Journal of Physical Chemistry A, 2011, 115(5): 741-746.

DOI：10.1021/jp110916m

In the present study, delocalization of a positive charge in pi-stacked multi-benzene rings in multilayered para- and meta-cyclophanes, in which benzene rings are connected by propyl chains to form a chromophore array with the face-to-face structure, was investigated by means of transient absorption spectroscopy during the pulse radiolysis using dichloroethane as a solvent. The local excitation and charge resonance (CR) bands were successfully observed. It was revealed that the CR band shifted to the longer wavelength side with the number of the benzene rings. The stabilization energy estimated from the peak position of the CR band showed the efficient charge delocalization over the cyclophanes. Furthermore, the CR bands showed the slight spectral change attributable to the change in distribution of the conformers. The substantially long lifetime of the CR band can be explained on the basis of the smaller charge distribution on the outer layers of the multilayered cyclophanes.

• 出版日期2011-2-10