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Volumn , Issue 15, 2008, Pages 2612-2620

Photosensitized electron transfer oxidation of sulfides: A steady-state study

Author keywords

Electron transfer; Oxidation; Photochemistry; Reaction mechanisms; Sulfides

Indexed keywords


EID: 53849136898     PISSN: 1434193X     EISSN: 10990690     Source Type: Journal    
DOI: 10.1002/ejoc.200800048     Document Type: Article
Times cited : (36)

References (92)
  • 39
    • 33745451791 scopus 로고
    • M. A. Fox, M. Chanon Eds, Elsevier, Amsterdam
    • b) M. A. Fox, M. Chanon (Eds.), Photoinduced Electron Transfer, Elsevier, Amsterdam, 1988, p. 475.
    • (1988) Photoinduced Electron Transfer , pp. 475
  • 45
    • 53849124274 scopus 로고    scopus 로고
    • In a previous study of the N-methylquinolinium photosensitization of sulfide 4, α-methylstyrene and 1-phenylethanol were also found. The percentage of the two compounds varied during irradiation, reasonably, owing to dehydration promoted by the acidity formed during the irradiation see ref.[5b
    • [5b]).
  • 46
    • 53849124969 scopus 로고    scopus 로고
    • 2/εa term is disregarded as no charge separation is involved.
    • 2/εa term is disregarded as no charge separation is involved.
  • 48
    • 0000135519 scopus 로고    scopus 로고
    • As an example of the ionization potential of the ethyl radical, values between 8.11 and 8.24 eV have been reported, see: a B. Ruscic, J. Berkowitz, L. A. Curtiss, J. A. Pople, J. Chem. Phys. 1989, 91, 114;
    • As an example of the ionization potential of the ethyl radical, values between 8.11 and 8.24 eV have been reported, see: a) B. Ruscic, J. Berkowitz, L. A. Curtiss, J. A. Pople, J. Chem. Phys. 1989, 91, 114;
  • 50
    • 0034248250 scopus 로고    scopus 로고
    • .) ≈ 1.00 V vs. SCE were estimated from the measured IP by the Miller equation, not taking into account the solvation energy which may heavily affect the result.
    • .) ≈ 1.00 V vs. SCE were estimated from the measured IP by the Miller equation, not taking into account the solvation energy which may heavily affect the result.
  • 53
    • 0001193680 scopus 로고    scopus 로고
    • 2CHSPh, see: F. G. Bordwell, X. Zhang, J. P. Cheng, J. Org. Chem. 1991, 56, 3216;
    • 2CHSPh, see: F. G. Bordwell, X. Zhang, J. P. Cheng, J. Org. Chem. 1991, 56, 3216;
  • 54
    • 0001233515 scopus 로고    scopus 로고
    • lower values were proposed for related derivatives, see: E. Baciocchi, C. Rol, E. Scamosci, G. V. Sebastiani, J. Org. Chem. 1991, 56, 5498.
    • lower values were proposed for related derivatives, see: E. Baciocchi, C. Rol, E. Scamosci, G. V. Sebastiani, J. Org. Chem. 1991, 56, 5498.
  • 55
    • 0012107209 scopus 로고
    • In related compounds it was found that the C-H energy changes by ≤1 kcal/mol when an EtS is substituted for a PhS group
    • In related compounds it was found that the C-H energy changes by ≤1 kcal/mol when an EtS is substituted for a PhS group: F. G. Bordwell, X. M. Zhang, J. Am. Chem. Soc. 1994, 116, 973.
    • (1994) J. Am. Chem. Soc , vol.11 , Issue.6 , pp. 973
    • Bordwell, F.G.1    Zhang, X.M.2
  • 56
    • 0000628641 scopus 로고    scopus 로고
    • .+ and thus BDFE reasonably negative for both radical cations.
    • .+ and thus BDFE reasonably negative for both radical cations.
  • 59
    • 53849112913 scopus 로고    scopus 로고
    • In the case of the benzyl cation, ΔG, 23.06[E°(A., E°PhCH2 , 37.3 kcal mol-1 with DCA and -25.4 kcal mol -1 with TPP, with PhCMe2, 24.2 and -28.8 kcal mol-1, and with Ph2CH+ 28.8 and 16.1 kcal mol-1
    • -1.
  • 60
    • 0035915374 scopus 로고    scopus 로고
    • The oxidation potential of α-thioalkyl radicals should not be significantly different to those of α-hydroxyalkyl radicals e.g, Me 2C.OH, 0.61 V vs. SCE, a value affected by a large uncertainty, which would make oxidation, at least by TPP, viable, see: T. Lund, D. D. M. Wayner, M. Jonsson, A. G. Larsen, K. Daasbjerg, J. Am. Chem. Soc. 2001, 123, 12590
    • +, viable, see: T. Lund, D. D. M. Wayner, M. Jonsson, A. G. Larsen, K. Daasbjerg, J. Am. Chem. Soc. 2001, 123, 12590.
  • 69
    • 53849135152 scopus 로고    scopus 로고
    • [5,6] although in every case subsequent paths from such intermediates to the sulfoxide are strongly exothermic.
    • [5,6] although in every case subsequent paths from such intermediates to the sulfoxide are strongly exothermic.
  • 72
    • 53849114266 scopus 로고    scopus 로고
    • Flash photolysis experiments with the Ph2S/TPP+ system showed no oxygen quenching of either the sulfide radical cation or of TPP.[6, whereas the lifetimes of both R2S, and DCA, was shortened in the corresponding experiments with DCA because of ET to O2 from the latter and reaction with O 2, of the former, path e, This proves that the rate constant for the reaction of both intermediates is kO2 < 1 × 106 M-1 S-1, but does not preclude this process having a role in steady-state experiments. Indeed, the reaction rate of R2S, with oxygen depends linearly on the intermediate concentration and thus on the intensity of the absorbed light flux, k[Intermediate][O2, rather than on the square of the flux as the reaction with superoxide, k[Intermediate] 2
    • 2 is more competitive at the low flux of steady-state irradiation than in flash experiments.
  • 73
    • 0002018403 scopus 로고    scopus 로고
    • There is some literature evidence that a further transient is involved in the reoxidation of the TPP. radical and it may well be that this is less efficient in BET than TPP, DCA, or O 2, Actually, it is known that TPP. is reoxidized to TPP+ by reaction with oxygen,[26] the reoxidation probably involves dimerization to TPP-TPP and SET to TPP-TPP, which cleaves to TPP, TPP, 10d] That TPP. ultimately gives back reoxidized TPP, is also indicated by the fact that this sensitizer is only partially consumed when used in solution and not at all when using the silica-absorbed or zeolited-encapsulated materials.[27, 26] D. Jacobi, W. Abraham, U. Pischel, L. Grubert, R. Stösser, W. Schnabbel, J. Chem. Soc. Perkin Trans. 2 1999, 1695
    • [27] [26] D. Jacobi, W. Abraham, U. Pischel, L. Grubert, R. Stösser, W. Schnabbel, J. Chem. Soc. Perkin Trans. 2 1999, 1695.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.