Photoinduced Electron Transfer Processes in Rotaxanes Containing [60]Fullerene and Ferrocene: Effect of Axle Charge on Light-Induced Molecular Motion

2006 ◽  
Vol 59 (3) ◽  
pp. 186 ◽  
Author(s):  
Atula S. D. Sandanayaka ◽  
Hisahiro Sasabe ◽  
Yasuyuki Araki ◽  
Nobuhiro Kihara ◽  
Yoshio Furusho ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Transient Absorption ◽  
Solvent Polarity ◽  
Orbital Method ◽  
Time Resolved ◽  
Transfer Processes ◽  
Recombination Processes ◽  
Electron Transfer Processes ◽  
Absorption Measurements

Two rotaxanes containing [60]fullerene (C60) as pendants on a crown-ether necklace, to which ferrocene (Fc) as axle stoppers were added, have been synthesized. One rotaxane has an ammonium cation in the centre of the axle (C60;Fc)Rot+ and the other has a neutral axle (C60;Fc)Rot. Optimized structures, calculated using a molecular orbital method, suggest that in the ground states (C60;Fc)Rot+ has a shorter distance between C60 and Fc than that of (C60;Fc)Rot. In both rotaxanes, efficient intra-rotaxane photoinduced electron-transfer processes have been observed by the selective excitation of C60 which acts as a photosensitized electron acceptor. The rates and efficiencies of the charge-separation and charge-recombination processes were evaluated by time-resolved fluorescence and transient absorption measurements with changing solvent polarity. From the different kinetic parameters between (C60;Fc)Rot+ and (C60;Fc)Rot, the light-induced molecular motions of these rotaxanes in the excited states and charge-separated states were separately revealed.

Photoinduced electron transfer processes in three component rotaxanes with porphyrins, [60]fullerene and triphenylamine

2006 ◽  
Vol 10 (12) ◽  
pp. 1346-1359 ◽  
Author(s):  
Hisahiro Sasabe ◽  
Yoshio Furusho ◽  
Atula S.D. Sandanayaka ◽  
Yasuyuki Araki ◽  
Nobuhiro Kihara ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Charge Separation ◽  
Transient Absorption ◽  
Photophysical Properties ◽  
Solvent Polarity ◽  
Time Resolved ◽  
Transfer Processes ◽  
Back Electron Transfer ◽  
Electron Transfer Processes ◽  
Absorption Measurements

Electron transfer processes occurring through-space and through-bond were studied for novel mechanically linked triad [2]rotaxanes, which contain a porphyrin (MP) unit as a pendant and [60]fullerene ( C 60) and triphenylamine ( TPA ) moieties as stopper groups at the axle ends (abbreviated as ( MP ; C 60- TPA ) rot+ with MP = H 2 P or ZnP . The photophysical properties were investigated by means of time-resolved fluorescence and transient absorption measurements with changing solvent polarity. The charge separation took place mainly via(1 MP *; C 60- TPA ) rot+ and ( MP ;1 C 60*- TPA ) rot + in polar solvents. Within the charge-separated states of triads ( MP ; C 60- TPA ) rot +, hole-shift and/or back electron transfer took place competitively. The lifetime of the charge separation state of ( ZnP ; C 60- TPA ) rot+ was similar to that of dyad ( C 60- TPA ) rot+ (140 ns in dimethylformamide), whereas that of ( H 2 P ; C 60- TPA ) rot + was as long as 230 ns, suggesting two final charge separation states such as ( MP ; C 60•-- TPA •+) rot + and ( MP •+; C 60•-- TPA ) rot+ depending on the kind of porphyrin.

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.

Direct observation of the photoinduced electron transfer processes of bis(4-arylphenylamino benzo)-ortho-carborane using transient absorption spectroscopic measurements

2017 ◽  
Vol 19 (36) ◽  
pp. 24485-24492 ◽  
Author(s):  
Mi Rang Son ◽  
Yang-Jin Cho ◽  
So-Yeon Kim ◽  
Ho-Jin Son ◽  
Dae Won Cho ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Direct Observation ◽  
Photoinduced Electron Transfer ◽  
Transient Absorption ◽  
Absorption Measurement ◽  
Spectroscopic Measurements ◽  
Transfer Processes ◽  
Electron Transfer Processes

The characteristic Cb˙− and Ar˙+ species of ortho-carborane triads generated by the photoinduced electron transfer are investigated by transient absorption measurement.

Photoinduced electron transfer from triplet states of phthalocyanines to fullerenes studied by transient absorption spectroscopies in visible and near-IR regions

2000 ◽  
Vol 04 (08) ◽  
pp. 713-721 ◽  
Author(s):  
MOHAMED E. EL-KHOULY ◽  
SHAFIQUL D.-M. ISLAM ◽  
MAMORU FUJITSUKA ◽  
OSAMU ITO
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Transient Absorption ◽  
Triplet States ◽  
Absorption Bands ◽  
Polar Solvents ◽  
Transfer Processes ◽  
Near Ir ◽  
Electron Transfer Processes ◽  
Electron Ejection

Photoinduced electron transfer processes between C 60/ C 70 and phthalocyanines such as tetra-tert-butylphthalocyanine ( H 2 TBPc ) and its zinc derivative ( ZnTBPc ) in polar solvents have been studied by observing the transient absorption spectra in the visible and near-IR regions. Upon predominant excitation of TBPcs with a 670 nm laser pulse in polar solvents, growth of the transient absorption bands of [Formula: see text] and [Formula: see text] was observed, accompanied by a concurrent decay of the triplet states of TBPcs (3 TBPc *). Thus it is confirmed that electron transfer occurs via 3 TBPc * in polar solvents. The electron transfer rate constants and efficiencies of electron transfer via 3 ZnTBPc * are greater than those via 3 H 2 TBPc * owing to the electron ejection ability of 3 ZnTBPc *. Solvent effects on the forward and backward electron transfer processes have been evaluated.

Time-Resolved Spectroscopic Study on Photoinduced Electron-Transfer Processes in Zn(II)porphyrin-Zn(II)chlorin-Fullerene Triad

ChemPhysChem ◽  
2003 ◽  
Vol 4 (9) ◽  
pp. 951-958 ◽  
Author(s):  
Jeong-Hyon Ha ◽  
Hyun Sun Cho ◽  
Dongho Kim ◽  
Jong-Cheol Lee ◽  
Tae-Young Kim ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Spectroscopic Study ◽  
Photoinduced Electron Transfer ◽  
Time Resolved ◽  
Transfer Processes ◽  
Electron Transfer Processes

Photoinduced electron and energy transfer processes in rotaxanes containing zinc porphyrin as pendant and [60]fullerene and ferrocene as axle ends

2005 ◽  
Vol 09 (10) ◽  
pp. 724-734 ◽  
Author(s):  
Mio Maes ◽  
Hisahiro Sasabe ◽  
Nobuhiro Kihara ◽  
Yasuyuki Araki ◽  
Yoshio Furusho ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Charge Separation ◽  
Transient Absorption ◽  
Recombination Rates ◽  
Time Resolved ◽  
Transient Absorption Spectra ◽  
Transfer Processes ◽  
Nonpolar Solvents ◽  
Electron Transfer Processes ◽  
Absorption Measurements

Photoinduced electron-transfer processes of a newly synthesized rotaxane containing porphyrinatozinc ( ZnP ), [60]fullerene ( C 60), and ferrocene ( Fc ) have been studied in terms of the time-resolved fluorescence and transient absorption measurements in polar and nonpolar solvents. In this rotaxane, ( ZnP ; C 60- Fc ) rotax , ZnP was chosen as a pendant of a crown-ether necklace, through which an axle with C 60 and Fc at both termini was penetrated. By the selective excitation of the ZnP moiety in a nonpolar solvent, energy transfer predominantly takes place to the C 60 moiety of ( ZnP ; C 60- Fc ) rotax . In polar solvents, charge-separation process takes place via the excited singlet state of the ZnP moiety in addition to the energy-transfer process. From the nanosecond transient absorption spectra, a clear absorption band of the C 60•− moiety was observed at 1000 nm as well as a broad absorption in the 600-800 nm region due to ZnP •+, suggesting the generation of ( ZnP •+; C 60•−- Fc ) rotax in the first step. Afterward, the hole-transferring process from ZnP •+ to Fc is thermodynamically possible, although this process is not fast because of its through-space process character. The final lifetimes of the C 60•− moiety were evaluated to be 290 and 370 ns in benzonitrile and DMF, respectively. The ratios of the charge-separation rates to charge-recombination rates were ca. 1000, indicating that ( ZnP ; C 60- Fc ) rotax affords an efficient photosynthetic model.

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