A Laser Flash Photolysis Study of the Intramolecular Energy Transfer Reaction from Benzophenone to Norbornadiene Covalently Bonded by a Rigid Steroid Bridge

A molecular pentad, comprised of zinc phthalocyanine ( ZnPc ) with four boron dipyrromethene units (BODIPY) have been examined by femtosecond and nanosecond laser flash photolysis to explore its photoinduced intramolecular events from the excited BODIPY. The geometry optimization showed that the phthalocyanine moiety is completely symmetric and form perfect square planar complex with zinc. The absorption spectrum of ZnPc -BODIPY pentad covers most of the visible region (ca. 300–750 nm), which clearly is an advantage for capturing solar energy. The excitation transfer from the singlet BODIPY to ZnPc is envisioned due to good spectral overlap of the BODIPY emission and ZnPc absorption spectra. Femtosecond laser flash photolysis studies provided concrete evidence for the occurrence of energy transfer from the singlet excited BODIPY to ZnPc in tetrahydrofuran. The kinetic study of energy transfer measured by monitoring the decay of the BODIPY emission revealed fast energy transfer (5.90 × 1010 s-1) in the molecular pentad. Since the electron transfer from the singlet ZnPc to BODIPY is thermodynamically not feasible, the singlet ZnPc decayed to populates the triplet ZnPc , in addition to the grounds state. These findings suggest the potential of the examined ZnPc -BODIPY pentad to be efficient photosynthetic antenna in the artificial photosynthetic systems.

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Energy Transfer, Electron Transfer, and Addition Reactions of Triplet State of 1,3-Dihydroimidazole-2-thiones Investigated by Laser Flash Photolysis

Bulletin of the Chemical Society of Japan ◽

10.1246/bcsj.72.339 ◽

1999 ◽

Vol 72 (3) ◽

pp. 339-345 ◽

Cited By ~ 3

Author(s):

Maksudul M. Alam ◽

Osamu Ito

Keyword(s):

Electron Transfer ◽

Energy Transfer ◽

Triplet State ◽

Flash Photolysis ◽

Laser Flash Photolysis ◽

Laser Flash ◽

Addition Reactions

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Silicon phthalocyanine-azobenzene-[60]fullerene light harvesting pentad: synthesis, characterization and electron transfer reaction studied by laser flash photolysis

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424613501046 ◽

2013 ◽

Vol 17 (11) ◽

pp. 1055-1063 ◽

Cited By ~ 6

Author(s):

Mohamed E. El-Khouly ◽

Jong-Hyung Kim ◽

Kwang-Yol Kay ◽

Shunichi Fukuzumi

Keyword(s):

Electron Transfer ◽

Transfer Reaction ◽

Flash Photolysis ◽

Laser Flash Photolysis ◽

Light Harvesting ◽

Visible Spectrum ◽

Laser Flash ◽

Electron Transfer Reaction ◽

Strong Light ◽

Silicon Phthalocyanine

Electron-transfer reaction of the newly synthesized light harvesting pentad composed of silicon phthalocyanine (SiPc) that is connected with two fullerene C 60 and two azobenzene units to form SiPc -(azobenzene)2-( C 60)2 pentad has been studied by laser flash photolysis and other complementary techniques. This combination between SiPc , azobenzene and C 60 in the examined SiPc -(azobenzene)2-( C 60)2 pentad leads to strong light absorption over the whole visible spectrum. Photoexcitation of the pentad results in rapid formation of the charge-separated state by photoinduced electron transfer from the singlet-excited state of the SiPc moiety to the C 60 moiety. The charge-separated state has a lifetime of 2.50 ns in benzonitrile.

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