Bimolecular Hole Transfer from the Trimethoxybenzene Radical Cation in the Excited State

2007 ◽  
Vol 111 (22) ◽  
pp. 4743-4747 ◽  
Author(s):  
Xichen Cai ◽  
Mamoru Fujitsuka ◽  
Tetsuro Majima
Keyword(s):  
Excited State ◽  
Radical Cation ◽  
Hole Transfer

Formation of dimer radical cation of 1,1-dianisylethylene through two-step hole transfer processes during TiO2 photocatalytic reactions

2004 ◽  
Vol 45 (19) ◽  
pp. 3753-3756 ◽  
Author(s):  
Takashi Tachikawa ◽  
Sachiko Tojo ◽  
Mamoru Fujitsuka ◽  
Tetsuro Majima
Keyword(s):  
Radical Cation ◽  
Hole Transfer ◽  
Transfer Processes ◽  
Photocatalytic Reactions ◽  
Dimer Radical Cation

Efficient Hole Transfer via Delocalized Excited State in Small Molecular Acceptor: A Comparative Study on Photodynamics of PM6:Y6 and PM6:ITIC Organic Photovoltaic Blends

2021 ◽  
pp. 2102764
Author(s):  
Shuyan Liang ◽  
Siying Li ◽  
Yannan Zhang ◽  
Tao Li ◽  
Haoxiang Zhou ◽  
...  
Keyword(s):  
Excited State ◽  
Comparative Study ◽  
Organic Photovoltaic ◽  
Hole Transfer

Near-Infrared Excitation of the peri-Xanthenoxanthene Radical Cation Drives Energy-Demanding Hole Transfer Reactions

2018 ◽  
Vol 122 (41) ◽  
pp. 23364-23370 ◽  
Author(s):  
Joseph A. Christensen ◽  
Jinyuan Zhang ◽  
Jiawang Zhou ◽  
Jordan N. Nelson ◽  
Michael R. Wasielewski
Keyword(s):  
Radical Cation ◽  
Near Infrared ◽  
Transfer Reactions ◽  
Hole Transfer ◽  
Infrared Excitation

Light-induced hole transfer in a hypervalent phosphorus(V) octaethylporphyrin bearing an axially linked bis(ethylenedithio)tetrathiafulvalene

2010 ◽  
Vol 14 (02) ◽  
pp. 178-187 ◽  
Author(s):  
Prashanth K. Poddutoori ◽  
Ann Dion ◽  
Songjie Yang ◽  
Melanie Pilkington ◽  
John D. Wallis ◽  
...  
Keyword(s):  
Steady State ◽  
Fluorescence Quenching ◽  
Radical Cation ◽  
High Efficiency ◽  
Chemical Oxidation ◽  
Reference Compound ◽  
Epr Spectrum ◽  
Hole Transfer ◽  
Time Resolved ◽  
Epr Measurements

A phosphorus(V) porphyrin bearing an axially linked bis(ethylenedithio)tetrathiafulvalene, dyad 1, and its radical cation phosphorus(V) porphyrin- O-CH2 -(bis(ethylenedithio)tetrathiafulvalene)+•, dyad 2, have been synthesized and studied as an electron hole donor-acceptor system. The absorption spectrum of dyad 1 does not show evidence for electronic coupling between the porphyrin and the bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) moieties. However, the steady-state fluorescence of the porphyrin chromophore is quantitatively quenched and its transient fluorescence lifetime is shortened compared to a reference compound in which the BEDT-TTF moiety is replaced by a methoxy group. Chemical oxidation of the BEDT-TTF moiety in dyad 1 to give dyad 2 results in recovery of the fluorescence intensity. This behavior suggests that the fluorescence quenching in dyad 1 is the result of intramolecular hole transfer from the the excited porphyrin to the BEDT-TTF moiety. The occurence of hole transfer in dyad 1 is confirmed by freeze-trapping and time-resolved electron paramagnetic resonance (EPR) measurements. The freeze-trapping EPR experiments show that steady-state irradiation of the complex leads to accumulation of its radical cation (dyad 2) while the transient EPR measurements at 5 °C show that flash irradiation of dyad 1 results in formation of a radical-ion pair with a lifetime of at least 300 ns. The triplet state of the porphyrin, which is formed by intersystem crossing and gives a strong transient EPR spectrum in the reference compound, is not observed for dyad 1. Together, the fluorescence quenching and the polarization pattern of the radical pair suggest that the hole transfer occurs from the excited singlet state of the porphyrin with high efficiency.

Resonance Raman spectra and excited-state geometry of the radical cation of p-dichlorobenzene

1989 ◽  
Vol 164 (4) ◽  
pp. 388-394 ◽  
Author(s):  
Tatsuhisa Kato ◽  
Naoki Muraki ◽  
Tadamasa Shida
Keyword(s):  
Excited State ◽  
Raman Spectra ◽  
Radical Cation ◽  
Resonance Raman ◽  
Resonance Raman Spectra

The importance of conformation in the reactivity of radical cations. Changing configuration at saturated carbon centres

1992 ◽  
Vol 70 (1) ◽  
pp. 272-279 ◽  
Author(s):  
Allyson L. Perrott ◽  
Donald R. Arnold
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Molecular Mechanics ◽  
Radical Cation ◽  
Trans Isomer ◽  
Radical Cations ◽  
Singlet Excited State ◽  
Photostationary State ◽  
Configurational Isomerization ◽  
Cis Isomer

Irradiation of an acetonitrile solution of cis 1-methyl-2-phenylcyclopentane (1bcis); 1,4-dicyanobenzene (2), an electron-accepting photosensitizer; and 2,4,6-collidine (3), a nonnucleophilic base, leads to configurational isomerization of the cyclopentane; the photostationary state lies > 99% in favour of the trans isomer. The mechanism proposed for this reaction involves formation of the radical cation of 1bcis by photoinduced electron transfer to the singlet excited state of 2, deprotonation of the radical cation assisted by the base 3, reduction of the resulting benzylic radical by the radical anion [Formula: see text], and reprotonation of the benzylic anion to give both the cis and the trans isomers of 1b. The photostationary state is controlled by the relative rates of deprotonation of the radical cations of 1bcis and trans; these rates are dependent upon the extent of overlap of the SOMO of the radical cation, which is largely associated with the phenyl ring, and the benzylic carbon–hydrogen bond. Molecular mechanics calculations (MM3 and MMP2) are used to calculate the preferred conformations of the isomers. The required orbital overlap is 31% effective with the global minimum conformation of the cis isomer and essentially ineffective for the low-lying conformations of the trans isomer. This proposed mechanism is supported by Stem–Volmer quenching studies, which indicate that both isomers quench the singlet excited state of 2 at the diffusion-controlled rate, and by deuterium incorporation studies. When irradiation of the cis isomer is carried out in acetonitrile–methanol-O-d as solvent, isomerization is accompanied by deuterium exchange at the benzylic position; the trans isomer is stable under these conditions. Keywords: photosensitized electron transfer, radical cation, deprotonation, configurational isomerization, conformation, molecular mechanics (MM3).

Novel Photoreactions of 2-Aza-1,4-dienes in the Triplet Excited State and via Radical-Cation Intermediates. 2-Aza-di-π-methane Rearrangements Yielding Cyclopropylimines andN-Vinylaziridines

2003 ◽  
Vol 68 (17) ◽  
pp. 6661-6671 ◽  
Author(s):  
Diego Armesto ◽  
Olga Caballero ◽  
Maria J. Ortiz ◽  
Antonia R. Agarrabeitia ◽  
Mar Martin-Fontecha ◽  
...  
Keyword(s):  
Excited State ◽  
Radical Cation ◽  
Triplet Excited State

Deciphering the excited-state dynamics and multicarrier interactions in perovskite core–shell type hetero-nanocrystals

Nanoscale ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 292-299
Author(s):  
Yinjuan Ren ◽  
Zhonghui Nie ◽  
Fei Deng ◽  
Ziming Wang ◽  
Siyang Xia ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Auger Recombination ◽  
Optical Gain ◽  
Charge Transfer State ◽  
Core Shell ◽  
Hole Transfer ◽  
Excited State Dynamics ◽  
Shell Type ◽  
Transfer State

We observed the hole transfer and confirmed the formation of charge transfer state in CsPbBr3@ZnS core–shell type NCs. The Auger recombination is largely suppressed, endowing the hetero-nanocrystals with unique optical gain properties.

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