Morphology and Photophysical Properties of One-Dimensional Arrayed Porphyrin Aggregates Assisted by Cyclodextrin Inclusion Complexation

Abstract

In this study, we investigated zinc-tetraphenylporphyrin/γ-cyclodextrin complex formation based on absorption, on fluorescence and circular dichroism spectroscopy, and on fluorescence decay measurement. When the cyclodextrin concentration increased, a new absorption and fluorescence peak appeared and then circular dichloism spectra suggested a chairal aggregate formation. These results indicated that the addition of γ-CD enhanced J-aggregate formation. The morphology of the obtained aggregates was directly observed by SEM and TEM, which showed one-dimensional rod-like structures of 30 nm in diameter and ca. 200 nm in length.

Keywords:

• cyclodextrin
• fluorescence
• J-aggregate
• morphology
• tetraphenylporphyrin

Acknowledgments

We would like to thank Prof. T. Kakuchi, Graduate School of Engineering, Hokkaido University, for the circular dichroism spectroscopic measurements. This work was supported by a Grant-in-Aid for Scientific Research (Nos. 20550001 and 21791929) from MEXT Japan, and by Grant-in-Aid for JSPS Fellows (No. 20–2850) from JSPS.