Excitation energy migration in a dodecameric porphyrin wheel.
Intramolecular excitation energy hopping (EEH) time within a dodecameric porphyrin wheel C6ZA, in which six meso-meso linked zinc(II) diporphyrin (Z2) subunits are bridged by 1,3-phenylene spacers, is deduced by a Förster energy hopping model based on S(1)-S(1) exciton-exciton annihilation and anisotropy depolarization. Under the assumption that the energy hopping sites are six Z2 subunits, two different observables (e.g., exciton-exciton annihilation and anisotropy depolarization times) consistently give the EEH time of 4.0 +/- 0.4 ps via 1,3-phenylene spacer of C6ZA, which is faster than 9.4 ps of linear 2Z2 (1,3-phenylene-linked zinc(II) tetraporphyrin). As a consequence, C6ZA serves as a well-defined two-dimensional model for a light-harvesting complex.
Hwang
In-Wook
IW
Center for Ultrafast Optical Characteristics Control and Department of Chemistry, Yonsei University, Seoul 120-749, Korea.
Ko
Dah Mee
DM
Ahn
Tae Kyu
TK
Yoon
Zin Seok
ZS
Kim
Dongho
D
Peng
Xiaobin
X
Aratani
Naoki
N
Osuka
Atsuhiro
A