Subpicosecond transient absorption study of intermolecular electron transfer between solute and electron-donating solvents

1992 ◽  
Vol 96 (20) ◽  
pp. 8042-8048 ◽  
Author(s):  
Hideki Kandori ◽  
Klaus Kemnitz ◽  
Keitaro Yoshihara
Keyword(s):  
Electron Transfer ◽  
Transient Absorption ◽  
Absorption Study ◽  
Intermolecular Electron Transfer

scholarly journals Photoinduced electron transfer in cyclophane-bridged porphyrin-quinone molecules. A subpicosecond transient absorption study

1996 ◽  
Vol 100 (12) ◽  
pp. 2076-2080 ◽  
Author(s):  
F. Pöllinger ◽  
C. Musewald ◽  
H. Heitele ◽  
M. E. Michel-Beyerie ◽  
C. Anders ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Transient Absorption ◽  
Absorption Study

A supramolecular Star Wars Tie Fighter Ship: electron transfer in a self-assembled triad composed of two zinc naphthalocyanines and a fullerene

2005 ◽  
Vol 09 (10) ◽  
pp. 698-705 ◽  
Author(s):  
Francis D'Souza ◽  
Suresh Gadde ◽  
Mohamed E. El-Khouly ◽  
Melvin E. Zandler ◽  
Yasuyaki Araki ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Charge Separation ◽  
Transient Absorption ◽  
Ion Pair ◽  
Spectral Studies ◽  
Stable Complex ◽  
Intermolecular Electron Transfer ◽  
Experimental Conditions ◽  
Time Resolved ◽  
Star Wars

Photoactive supramolecules composed of electron donor and electron acceptor entities are important for light energy harvesting applications. In the present study, a Star Wars Tie Fighter Ship shaped supramolecular triad was constructed by self-assembling two zinc naphthalocyanines to a fulleropyrrolidine bearing two pyridine entities using an axial coordination approach. Optical absorption and emission studies revealed stable complex formation, and the experimentally determined free-energy change revealed the possibility of electron transfer from singlet excited zinc naphthalocyanine to the fulleropyrrolidine. The picosecond time-resolved emission technique was utilized to evaluate the kinetics of charge separation while nanosecond transient absorption spectral studies provided evidence for electron transfer quenching. The measured charge-separation rate, k CS and quantum yield, Φ CS were found to be 5.7 × 109 s −1 and 0.93 in toluene, respectively, indicating an efficient process within the supramolecular triad. The charge recombination rate (k CR ) of the supramolecular ion-pair calculated from the nanosecond transient absorption technique was found to be 3.5 × 107 s −1 yielding a lifetime for the radical ion-pair (τ RIP ) of about 30 ns. Changing the solvent from the noncoordinating toluene to the coordinating benzonitrile or THF destroyed the supramolecular structure, and under these experimental conditions, only intermolecular electron transfer from the triplet excited zinc naphthalocyanine to fulleropyrrolidine could be observed. Under these conditions, the measured electron transfer rates, k et , T inter , were found to be 2.6 × 107 M −1. s −1 in benzonitrile and 1.2 × 107 M −1. s −1 in THF, respectively.

Photoinduced electron-transfer processes between phthalocyanines and perylene derivatives

2006 ◽  
Vol 10 (10) ◽  
pp. 1190-1196 ◽  
Author(s):  
Koji Kitazume ◽  
Yu Chen ◽  
Mitsunari Itou ◽  
Yasuyuki Araki ◽  
Satoshi Uchida ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Transient Absorption ◽  
Triplet States ◽  
Intermolecular Electron Transfer ◽  
Absorption Bands ◽  
Time Resolved ◽  
Transfer Processes ◽  
Perylene Derivatives ◽  
Electron Transfer Processes

Photoinduced electron-transfer processes between phthalocyanines ( H2Pc and ZnPc ) as electron donors and perylene derivatives as electron acceptors have been studied using a time-resolved, nanosecond transient absorption method in benzonitrile. The observed findings show that intermolecular electron transfer takes place via the excited triplet states of ZnPc and H2Pc , as confirmed by the characteristic transient absorption bands in the near-IR region. The visible light excitation of the mixtures of H2Pc and the perylene derivatives adsorbed onto TiO2gave a relatively high photovoltaic efficiency.

Light harvesting phthalocyanine/subphthalocyanine system: intermolecular electron-transfer and energy-transfer reactions via the triplet subphthalocyanine

2011 ◽  
Vol 15 (02) ◽  
pp. 111-117 ◽  
Author(s):  
Mohamed E. El-Khouly ◽  
Shunichi Fukuzumi
Keyword(s):  
Electron Transfer ◽  
Energy Transfer ◽  
Excited State ◽  
Transfer Process ◽  
Radical Anion ◽  
Transient Absorption ◽  
Nanosecond Laser ◽  
Triplet Excited State ◽  
Intermolecular Electron Transfer ◽  
Absorption Bands

Photoinduced electron transfer from the electron-donating zinc tetra-tert-butylphthalocyanine, ZnTBPc , to the electron-accepting dodecafluorosubphthalocyanine, SubPcF12 , in the polar benzonitrile has been investigated with nanosecond laser photolysis method. The examined ZnTBPc/SubPcF12 mixture absorbs the light in a wide section of the UV/vis/NIR spectra. Owing to the particular electronic properties of both entities, such combination seems to be perfectly suited for the study of intermolecular electron-transfer process in the polar solvents via the triplet-excited state of SubPcF12 . Upon excitation of SubPcF12 with 570 nm laser light in polar benzonitrile (εs = 25.2), the electron transfer from ZnTBPc to the triplet-excited state of SubPcF12 was confirmed by observing the transient absorption bands of ZnTBPc radical cation and SubPcF12 radical anion in the visible and near-IR region. On addition of an appropriate electron acceptor with excellent electron-accepting properties, namely dicyanoperylene-3,4,9,10-bis(dicarboximide) ( PDICN2 ), the anion radical of SubPcF12 transfers to the PDICN2 yielding the PDICN2 radical anion. These observations confirm the photosensitized electron-transfer/electron-mediating cycle of ZnTBPc/SubPcF12/PDICN2 system. In non-polar toluene (εs = 2.2), the energy-transfer process from the triplet-excited state of SubPcF12 to the low-lying triplet state of ZnTBPc was confirmed by the consecutive appearance of the triplet ZnTBPc .

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