Reduction of tetranitromethane by electronically excited aromatics in acetonitrile: Spectra and molar absorption coefficients of radical cations of anthracene, phenanthrene and pyrene

Naqvi, K. Razi; Melø, Thor Bernt

doi:10.1016/j.cplett.2006.07.033

Cited by 16 publications

(17 citation statements)

References 27 publications

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“…In the transienta bsorption spectra of Acr + -An ( Figure 3a, the absorption due to the anthracene radicalc ation is clearly detected at 720 nm, which agrees with the absorption maxi-mum of the anthracene radical cation. [48,53] In this case, the transient absorption at 720 nm as well as at 580 nm decayst o zero in the observed time range up to 1ns. This indicates that the singlet ET state decays to the ground state with al ifetime of 90 ps prior to ISC to the tripletE Tstate.…”

Section: Formation Of Et States Of Acrmentioning

confidence: 74%

Photoinduced Electron Transfer in 9‐Substituted 10‐Methylacridinium Ions

Tsudaka

Kotani

Ohkubo

et al. 2016

Chemistry A European J

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A series of 9-substituted 10-methylacridinium ions (Acr -R) in which an electron-donor moiety (R) is directly linked with an electron-acceptor moiety (Acr ) at the 9-position was synthesized, and the photodynamics was fully investigated to determine the rate constants of photoinduced electron transfer (ET) and back electron transfer. The driving forces of photoinduced electron transfer and back electron transfer were determined by means of electrochemical and photophysical measurements. The dependence of the ET rate constants on driving force was well analyzed in the light of the Marcus theory of ET. The quantum yields of formation of the triplet ET states vary significantly, depending on the interaction between the donor (R) and acceptor (Acr ) moieties. Among the Acr -R examined, the 9-mesityl-10-methylacridinium ion (Acr -Mes) exhibits the best performance in terms of the lifetime of the triplet ET state and the quantum yield. Photoexcitation of Acr -Mes results in formation of the triplet ET state [ (Acr -Mes )], which has a long lifetime, a high energy (2.37 eV), and a high quantum yield (>75 %) in acetonitrile. The triplet ET state exhibits both the oxidizing and reducing activity of the Mes and Acr moieties, respectively.

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Section: Formation Of Et States Of Acrmentioning

confidence: 74%

Photoinduced Electron Transfer in 9‐Substituted 10‐Methylacridinium Ions

Tsudaka

Kotani

Ohkubo

et al. 2016

Chemistry A European J

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“…Considering that the electron transfer from anthracene to 2 becomes exergonic (DG et = À0.17 eV), electron transfer from anthracene to 2 occurred to produce an anthracene radicalc ation, for which an absorption band at 710 nm was clearly observed upon mixing anthracene and 2,a nd then the anthracene radical cation decayed at af ast rate ( Figure 6). [12,25,26] Because the decay rate constantsi nt hese cases increased with an increasei nt he anthracene concentration ( Supporting Information, FigureS11), the rate constanto f electron transfer (k et )f rom anthracene to 2 was determined from the slope of the decay rate constantsv ersust he concen- [a] The k et values for the electron transfer from anthracene, 9-methylanthracene, and 9,10-dimethylanthracene to 1 were obtained by dividing the second-order rate constants( k 2 )b yt he numbers of electron fort he multi-electrono xidations (k 2 = 6k et for anthracene, k 2 = 4k et for 9-methylanthracene, and k 2 = 2k et for 9,10-dimethylanthracene, respectively). tration of anthracene.…”

Section: Resultsmentioning

confidence: 99%

Multi‐Electron Oxidation of Anthracene Derivatives by Nonheme Manganese(IV)‐Oxo Complexes

Sharma

Jung

Lee

et al. 2017

Chemistry A European J

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Six-electron oxidation of anthracene to anthraquinone by a nonheme Mn -oxo complex, [(Bn-TPEN)Mn (O)] , proceeds through a rate-determining electron transfer from anthracene to [(Bn-TPEN)Mn (O)] , followed by subsequent fast oxidation reactions to give anthraquinone. The reduced Mn complex ([(Bn-TPEN)Mn ] ) is oxidized by [(Bn-TPEN)Mn (O)] rapidly to produce the μ-oxo dimer ([(Bn-TPEN)Mn -O-Mn (Bn-TPEN)] ). The oxygen atoms of the anthraquinone product were found to derive from the manganese-oxo species by the O-labelling experiments. In the presence of Sc ion, formation of an anthracene radical cation was directly detected in the electron transfer from anthracene to a Sc ion-bound Mn (O) complex, [(Bn-TPEN)Mn (O)-(Sc(OTf) ) ] , followed by subsequent further oxidation to yield anthraquinone. When anthracene was replaced by 9,10-dimethylanthracene, electron transfer from 9,10-dimethylanthracene to [(Bn-TPEN)Mn (O)-(Sc(OTf) ) ] occurred rapidly to produce stable 9,10-dimethylanthracene radical cation. The driving force dependence of the rate constants of electron transfer from the anthracene derivatives to [(Bn-TPEN)Mn (O)] and [(Bn-TPEN)Mn (O)-(Sc(OTf) ) ] was well-evaluated in light of the Marcus theory of electron transfer.

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“…Also appearing in the spectrum are a diminished bleach for RuðbpyÞ 3 2þÃ at 450 nm and the characteristic triplet-triplet Acr- 3 An absorption feature at 430 nm. Anthracene cation absorptions appear at 430 and 720 nm (36)(37)(38), which grow at the expense of Acr-3 An. Reduced MV þ appears even with initial concentrations of MVðPF 6 Þ 2 as low as 0.5 mM.…”

Section: Resultsmentioning

confidence: 99%

Sensitization of ultra-long-range excited-state electron transfer by energy transfer in a polymerized film

Ito

Fang

Brennaman

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Distance-dependent energy transfer occurs from the Metal-toLigand Charge Transfer (MLCT) excited state RuðbpyÞ 3 2þÃ to an anthracene-acrylate derivative (Acr-An) incorporated into the polymer network of a semirigid poly(ethyleneglycol)dimethacrylate monolith. Following excitation, RuðbpyÞ 3 2þÃ to Acr-An triplet energy transfer occurs followed by long-range, Acr-3 An-Acr-An → Acr-An-Acr-3 An, energy migration. With methyl viologen dication (MV 2þ ) added as a trap, Acr-3 An þ MV 2þ → Acr-An þ þ MV þ electron transfer results in sensitized electron transfer quenching over a distance of approximately 90 Å.luminescence | time-resolved spectroscopy | polymer matrix M olecular level electron and energy transfer in rigid and semirigid media are important in applications from imaging to electron transfer in biological membranes (1-4). In photosystem II, the chlorophyll singlet excited state 1 P 680 Ã is formed by light absorption by an antenna complex followed by highly efficient long-range energy transfer sensitization (5). Oxidative quenching of 1 P 680 Ã is followed by electron transfer activation of the Oxygen Evolving Complex (OEC) where water is oxidized to oxygen.Although well understood in solution (6-10), molecular level electron and energy transfer are less well understood in rigid media where diffusion is inhibited and reaction barriers significantly altered (11). There is theoretical (12, 13) and experimental insight into both processes in rigid media with the latter studied largely in low temperature glasses and, to a lesser extent, in plastics and polymeric films (14-17). Important fundamental issues remain to be elucidated along with the possible exploitation of randomly oriented, fixed site geometries in local and long-range electron and energy transfer applications.Poly(ethyleneglycol)dimethacrylate (PEG-DMA) films and monoliths, Fig. 1A, or photochemical polymerization under mild conditions (21, 22) to give optically transparent materials with features conformable to the nanoscale. They have proven useful in exploring medium effects on the properties of Metal-to-Ligand Charge Transfer (MLCT) excited states (23). Here, we report the use of a MLCT excited state in demonstrating sensitized electron transfer induced by ultralong-range energy transfer over a distance of approximately 90 Å.Structures relevant to the study are shown in Fig. 1A. They include the PEG-DMA derivative with n ¼ 9 (PEG-DMA550), the salt ½RuðbpyÞ 3 ðPF 6 Þ 2 , (bpy is 2,2′-bipyridine), and an acrylate derivative of anthracene (Acr-An). The acrylate tail allows the energy and electron transfer active anthracene group to be incorporated into the polymer network as it forms. Fig. 1 B and C show corrected emission spectra and emission decay profiles, respectively, for RuðbpyÞ 3 2þÃ with and without added Acr-An in poly-PEG-DMA550. The data provide clear evidence for emission quenching by Acr-An. Emission intensity measurements show that quenching was 55% complete with 300 mM AcrAn in the initial solution. Time-resolved emission measure...

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Reduction of tetranitromethane by electronically excited aromatics in acetonitrile: Spectra and molar absorption coefficients of radical cations of anthracene, phenanthrene and pyrene

Cited by 16 publications

References 27 publications

Photoinduced Electron Transfer in 9‐Substituted 10‐Methylacridinium Ions

Photoinduced Electron Transfer in 9‐Substituted 10‐Methylacridinium Ions

Multi‐Electron Oxidation of Anthracene Derivatives by Nonheme Manganese(IV)‐Oxo Complexes

Sensitization of ultra-long-range excited-state electron transfer by energy transfer in a polymerized film

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