Anomalously high rate constants for the reaction of solvent positive ions with soluts in irradiated cyclohexane and methylcyclohexane

Zador, E.; Warman, John M.; Hummel, Andries

doi:10.1016/0009-2614(73)85098-5

Cited by 56 publications

(13 citation statements)

References 13 publications

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“…However, in radiolysis, the rate of reaction of solutes, including CCl 4 with the positive hole CCl 4 + , is given as being in excess of 10 11 LM ‐1 s ‐1 and is much faster than diffusion controlled. Similar rapid movement of positive holes in liquids have been observed in other pulse‐radiolysis studies (18, 22). These data suggest that the origin of the 475 nm species, namely CCl 3 + ‖ Cl ‐ is different in two‐photon photolysis from that in radiolysis.…”

Section: Discussionsupporting

confidence: 86%

“…Qualitatively, a similar effect is observed in photolysis, but unfortunately, the inefficiency of C 6 H 12 in reducing the species does not enable a large range of quenching to be observed. Figures 6 and Figures 7 illustrate the effect of plotting these data via a Stem Volmer plot or via a geminate recombination process (18, 22, 23).…”

Section: Discussionmentioning

confidence: 99%

“…The abnormally high transport rate of the hole in liquid CCl 4 is of direct interest in kinetic studies. Other examples exist in radiation chemistry, for example, the mobility of the hole in cyclohexane is 10‐fold larger than that expected by simple diffusion (18). Initial studies (17) indicate that similar effects may be observed with two‐photon photolysis of CCl 4 .…”

Section: Introductionmentioning

confidence: 99%

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The Laser Two-photon Photolysis of Liquid Carbon Tetrachloride†

Zhang

Thomas

2006

Photochem Photobiol

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The two-photon photolysis of liquid CCl4 with 25 ps pulses of 266 nm light has been studied and compared with similar studies with high energy radiation. Both neutral and ionic species are produced from excited states and ionization. The emphasis of the study is on the ionic processes, while some data related to excited states and free radicals are presented. In both radiolysis and photolysis, a solvent separated charged pair, CCl3+ // Cl-, exhibiting a lambda(max) at 475 nm, is observed that exhibits a total growth over 38 to 100 ps. Solutes with ionization potentials less than that of CCl4 (11.47 eV) reduce the yield of the 475 nm species producing radical cations of the solute. The efficiency of this process is about 10-fold larger in radiolysis compared with photolysis. Analysis of the data suggest that the lower energy of two-photon photolysis produces a charge pair CCl4+ // CCl4-, which decays in about 3 ps to CCl4+ // Cl-. This species then decays to CCl3+ // Cl-. The lifetime of the growth of the 475 nm is measured as 46 ps. These studies clearly show areas where radiolysis and photolysis can be quite similar and also areas where the vast difference in excitation energy introduces stark differences in the observed radiation and photoinduced chemistry.

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Section: Discussionsupporting

confidence: 86%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Laser Two-photon Photolysis of Liquid Carbon Tetrachloride†

Zhang

Thomas

2006

Photochem Photobiol

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“…The most obvious model for explaining the observed experimental effects is that intermediately formed vibronically excited donor cations decay by competing relaxation and dissociation, see e.g. reaction sequence (14). This should be independent of the bending motion of the donor molecule (ArXH).…”

Section: Alternative Attemptsmentioning

confidence: 99%

“…This is supported by the observation of the high mobility of the solvent radical cations (''hopping'') in non-polar media. 14,15 In spite of the logical prediction that the solute radical cation is the only product of FET from the donor to the solvent radical cation (2), a surprising two-product situation has been observed in experiments involving hetero group substituted aromatic moieties. Hence, a synchronous and immediate formation of the radical cations and of the corresponding radicals has been found as shown on the example of the ionization of phenol (ArOH) via FET in n-butyl chloride as solvent, 16 cf.…”

Section: Introductionmentioning

confidence: 99%

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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Charge Transfer from the Carbon Tetrachloride Radical Cation to Alkyl Chlorides, Alkanes, Alkenes and Aromatics

Mehnert¹,

Brede²,

Bös³

et al. 1979

Ber Bunsenges Phys Chem

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Charge transfer from carbon tetrachloride radical cations to 17 solutes (alkyl chlorides, n‐ and c‐alkanes, alkenes and aromatics) was studied by pulse radiolysis. ‐ At gas‐phase ionization potential differences ΔI = (ICCl4 ‐ Is) smaller than 0.8 eV rate constants of the reaction up to two orders of magnitude lower than expected for a diffusion controlled reaction have been determined. The dependence of the rate constants on the ionization potential differences k vs. ΔI is explained in terms of a two‐step process consisting of migration of solvent cations and electron transfer from the scavenger molecule to the solvent cation. The probability of the last step was calculated using the Franck‐Condon principle. In the framework of a simplified model taking into account vibrational stretching and deformation modes reasonable fits of the k vs. ΔI behaviour were obtained.

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Anomalously high rate constants for the reaction of solvent positive ions with soluts in irradiated cyclohexane and methylcyclohexane

Cited by 56 publications

References 13 publications

The Laser Two-photon Photolysis of Liquid Carbon Tetrachloride†

The Laser Two-photon Photolysis of Liquid Carbon Tetrachloride†

Free electron transfer—relations between molecule dynamics and reaction kinetics

Charge Transfer from the Carbon Tetrachloride Radical Cation to Alkyl Chlorides, Alkanes, Alkenes and Aromatics

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