Rapid Exciton Migration and Fluorescent Energy Transfer in Helical Polyisocyanides with Regularly Arranged Porphyrin Pendants
Rapid Exciton Migration and Fluorescent Energy Transfer in Helical Polyisocyanides with Regularly Arranged Porphyrin Pendants
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DOI：
10.1021/jp047753i
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发表时间：
2004-07
影响因子：
3.3
通讯作者：
M. Fujitsuka;A. Okada;S. Tojo;F. Takei;K. Onitsuka;Shigetoshi Takahashi;T. Majima
中科院分区：
文献类型：
--
作者：
M. Fujitsuka;A. Okada;S. Tojo;F. Takei;K. Onitsuka;Shigetoshi Takahashi;T. Majima
用稳态和瞬态光谱方法研究了一系列含卟啉侧基的多异氰酸酯（卟啉聚合物）的光物理性质。游离碱卟啉聚合物的B（Soret）-带显示分裂，表明卟啉聚合物中由于面对面堆积构象而发生的大量激子耦合。另一方面，锌卟啉聚合物的B带分裂成四个峰，表明偏离严格的面对面堆积构象。与相应的单体和二聚体相比，卟啉聚合物的荧光量子产率较小。此外，卟啉聚合物的荧光衰减曲线偏离单指数衰减由于聚合物的结构异质性。结果表明，卟啉聚合物显示出瞬态吸收变化，这归因于激子-激子湮灭伴随着结构变化，速率常数为（2 - 4）× 1010 s-1。
Photophysical properties of a series of polyisocyanides possessing porphyrin pendants (porphyrin polymers) were investigated by steady state and transient spectroscopic methods. The B (Soret)-band of the free base porphyrin polymers showed splitting indicating substantial exciton coupling in the porphyrin polymers due to a face-to-face stacking conformation. On the other hand, the B-band of the zinc porphyrin polymers split into four peaks indicating deviation from the strict face-to-face stacking conformation. The fluorescence quantum yields of the porphyrin polymers were small compared with those of the corresponding monomers and dimers. Furthermore, the fluorescence decay profiles of the porphyrin polymers deviated from single-exponential decay due to the structural heterogeneity of the polymers. It was revealed that the porphyrin polymers showed transient absorption changes attributable to the exciton−exciton annihilation accompanying structural change with the rate constant of (2−4) × 1010 s-1 regard...