Indication of molecular oscillations during free electron transfer: reaction of butyl chloride parent ions with benzyltrimethylsilanes

Brede, O.; Hermann, Ralf; Naumov, Sergej; Perdikomatis, Gerasimos P.; Zarkadis, Antonios K.; Siskos, Michael G.

doi:10.1016/s0009-2614(03)01011-x

Cited by 12 publications

(15 citation statements)

References 16 publications

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“…In this case, however, an inverse electron shift exists in so far that p electrons from the aromatic ring are shifted towards the substituents. This is different from the phenol situation, 40,41 see Fig. 7.…”

Section: Benzylsilanesmentioning

confidence: 67%

See 1 more Smart Citation

Free electron transfer—relations between molecule dynamics and reaction kinetics

Brede¹,

Naumov²

2010

Chem. Soc. Rev.

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Electron transfer in non-polar media (alkanes, alkyl chlorides) exhibits some essential peculiarities. For instance the reaction of hetero-substituted aromatics with parent solvent radical cations results in the parallel formation of metastable donor radical cations and fragmentation products, in comparable amounts. The fragmentation products originate from a dissociative donor radical cation which decays extremely rapidly, i.e., in a few femtoseconds. This phenomenon is explained in terms of intramolecular dynamic motions which cause changes of the electron density (pi- and n-orbitals) in dependence on the deformation angle between the substituents and the aromatic ring. Hence femtosecond dynamics is reflected in the nanosecond time range and can be observed with real-time spectroscopy. Therefore, the process is named free electron transfer (FET) which corresponds to an unhindered electron jump occurring in the first approach of the reactants. This dynamic controlled process is compared with the classical electron transfer theories which are based on equilibrium kinetics. From the FET mechanism some new aspects for chemical reaction kinetics can be derived (critical review, 69 references).

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Section: Benzylsilanesmentioning

confidence: 67%

“…In these cases the dissociation of the unstable donor radical cation yields benzyl radicals as well as silyl cations. [40][41][42] Table 2 gives the dynamic, energetic and product ratio data belonging for them.…”

Section: Benzylsilanesmentioning

confidence: 99%

Free electron transfer—relations between molecule dynamics and reaction kinetics

Brede¹,

Naumov²

2010

Chem. Soc. Rev.

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“…As a further example, the ionization of benzyltrimethylsilanes has been reported recently. 6,7 In this paper, as the deciding factor of influence on FET the rotation ability of the substituent at the aromatic ring has been demonstrated experimentally.…”

Section: Discussionmentioning

confidence: 98%

“…Recently it was found that the electron tra/>nsfer ionization of arenes (Ar) substituted with rotating groups such as -OH, -SH, SeH, -CH 2 SiMe 3 etc. yields two characteristic direct products, [5][6][7] as formulated for phenols in reaction (2).…”

Section: Introductionmentioning

confidence: 99%

Ionization of the three isomeric hydroxybenzoates by free electron transfer: product distribution depends on the mobility of the phenoxyl group

Brede

Hermann

Karakostas

et al. 2004

Phys. Chem. Chem. Phys.

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“…Over the past few decades, they have been studied with the focus on biological (e.g., photosynthesis, DNA cleavage) [1] and technological (e.g., lightemitting diodes [LED] production, photo-resist materials) [2] aspects. Both 10-methylacridinium cation and benzyltrimethylsilane were studied extensively in recent years, mainly due to the low photoexcitation energy and a negligibly small triplet formation quantum yield (U isc \ 0.001) of the former [3][4][5] and a relatively small photoionization energy of the latter [6,7]. The one-electron transfer process within the excited donor-acceptor pair produces initial radicals which undergo further, secondary reactions, leading to the formation of stable products.…”

Section: Introductionmentioning

confidence: 99%

Photoinduced electron transfer reactions in the 10-methylacridinium cation–benzyltrimethylsilane system: steady-state and flash photolysis studies

et al. 2009

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The mechanism of the photoinduced reaction of the lowest excited singlet state of the 10-methylacridinium (AcrMe ? ) cation with benzyltrimethylsilane (BTMSi) in acetonitrile has been investigated by means of steady-state and time-resolved methods. A variety of stable products was found after irradiation (365 nm) of the reaction mixture under aerobic and oxygen-free conditions. The stable products were identified and analyzed using UV-Vis spectrophotometry, high performance liquid chromatography (HPLC), and mass spectrometry (MS). Based on Stern-Volmer plots of the AcrMe ? fluorescence quenching by BTMSi (using fluorescence intensity and lifetime measurements), the rate constants were determined to be k q = 1.24 (± 0.02) 9 10 10 M -1 s -1 and k q = 1.23 (± 0.02) 9 10 10 M -1 s -1 , i.e., close to the diffusion-controlled limit in acetonitrile, indicating the dynamic quenching mechanism. The quenching process was shown to occur via an electron-transfer reaction leading to the formation of acridinyl radicals (AcrMe • ) and C 6 H 5 CH 2 Si(CH 3 ) 3•? radical cations. Based on stationary and flash photolysis experiments, a detailed mechanism of the secondary reactions is proposed and discussed. The AcrMe • radical was shown to decay by two processes. The fast decay, observed on the nanosecond timescale, was attributed to the back-electron transfer occurring within the initial radical ion pair. The slow decay on the microsecond timescale was explained by recombination reactions of radicals which escaped from the radical pair, including benzyl radicals formed via C-Si bond cleavage in the C 6 H 5 CH 2 Si(CH 3 ) 3•? radical cation.

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Indication of molecular oscillations during free electron transfer: reaction of butyl chloride parent ions with benzyltrimethylsilanes

Cited by 12 publications

References 16 publications

Free electron transfer—relations between molecule dynamics and reaction kinetics

Free electron transfer—relations between molecule dynamics and reaction kinetics

Ionization of the three isomeric hydroxybenzoates by free electron transfer: product distribution depends on the mobility of the phenoxyl group

Photoinduced electron transfer reactions in the 10-methylacridinium cation–benzyltrimethylsilane system: steady-state and flash photolysis studies

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