Synthesis and Photophysical Properties of Two Diazaporphyrin鈥揚orphyrin Hetero Dimers in Polar and Nonpolar Solutions

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• 作者：Fawzi Abou-Chahine ; Daisuke Fujii ; Hiroshi Imahori ; Haruyuki Nakano ; Nikolai V. Tkachenko ; Yoshihiro Matano ; Helge Lemmetyinen
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：June 18, 2015
• 年：2015
• 卷：119
• 期：24
• 页码：7328-7337
• 全文大小：553K
• ISSN：1520-5207

文摘

Two diazaporphyrin (DAP)-porphyrin hetero dimers, in 尾鈥?i>meso and 尾鈥撐?configurations, were prepared to study their photoinduced intramolecular electron transfer properties. The two meso nitrogen atoms in the porphyrin ring of DAP change its redox potential, making DAP more easily reduced, compared to its porphyrin counterpart. A charge-transfer from porphyrin to DAP in both hetero dimers was verified by versatile optical spectroscopic methods. The steady-state fluorescence spectra indicated an efficient intramolecular exciplex formation for both dimers. For the 尾鈥?i>meso dimer, ultrafast time-resolved spectroscopic methods revealed the subpicosecond formation of two types of primary short-living (1鈥?8 ps) intramolecular exciplexes, which relaxed in toluene to form a long-living final exciplex (1.4 ns) followed by a longer-living charge transfer complex (>5 ns). However, in benzonitrile, the lifetime of the final exciplex was longer (660 ps) as was that of the charge transfer complex (180 ps). The 尾鈥撐?analogue formed similar short-living exciplexes in both solvents, but the final exciplex and the charge transfer state had significantly shorter lifetimes. The electrochemical redox potential measurements and density functional theory calculations supported the proposed mechanism.