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Volumn 126, Issue 6, 2004, Pages 1830-1835

Laser Flash Photolysis of tert-Butyl Aroylperbenzoates: Kinetics of the Singlet and Triplet States and the Aroylphenyl Radicals

Author keywords

[No Author keywords available]

Indexed keywords

CHEMICAL BONDS; FREE RADICALS; LASER APPLICATIONS; LIGHT ABSORPTION; MONOMERS; PHOTOLYSIS; RATE CONSTANTS; SOLVENTS; THERMAL EFFECTS;

EID: 1242291813     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja030231g     Document Type: Article
Times cited : (28)

References (68)
  • 1
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    • note
    • Contribution 481 from the Center for Photochemical Sciences.
  • 4
    • 0142174563 scopus 로고    scopus 로고
    • Scranton, A. B., Bowman, C. N., Peiffer, R. W., Eds.; ACS Symposium Series 673; American Chemical Society: Washington, DC
    • (b) Lai, Y.; Quinn, E. T. Photopolymerization Fundamentals and Applications; Scranton, A. B., Bowman, C. N., Peiffer, R. W., Eds.; ACS Symposium Series 673; American Chemical Society: Washington, DC, 1997; p 35.
    • (1997) Photopolymerization Fundamentals and Applications , pp. 35
    • Lai, Y.1    Quinn, E.T.2
  • 10
    • 1242280030 scopus 로고    scopus 로고
    • U.S. Patent 4,754,659, 1988
    • (a) Neckers, D. U.S. Patent 4,754,659, 1988.
    • Neckers, D.1
  • 11
    • 1242280029 scopus 로고    scopus 로고
    • Eur. Patent 126541 Al, 1984
    • (b) Takeshi, K.; Mamoru, S. Eur. Patent 126541 Al, 1984.
    • Takeshi, K.1    Mamoru, S.2
  • 12
    • 1242324781 scopus 로고    scopus 로고
    • U.S. Patent 4,498,963, 1983
    • (c) Neckers, D. C. U.S. Patent 4,498,963, 1983.
    • Neckers, D.C.1
  • 46
    • 0037657978 scopus 로고    scopus 로고
    • After the submission of this paper, it came to our attention that similar absorption of the singlet state of benzophenone in water has been observed by Ramseier et al. (J. Phys. Chem. A 2003, 107, 3305).
    • (2003) J. Phys. Chem. A , vol.107 , pp. 3305
  • 50
    • 0010850727 scopus 로고
    • The aroyloxyl radicals are known to show absorption in the 600-800 nm range and their reported lifetimes are 0.2-0.5 μs (ref 14). However, we observed no absorption in that range during our experiments, and attempts to observe the aroylbenzoyloxyl radicals were unsuccessful. Ingold and co-workers (ref 14b) had studied a single aroylbenzoyl peroxide and, as was the case with the system we report in this paper, saw no aroylbenzoyloxyl radical absorption. One of the reviewers has pointed out that two-photon absorption could be responsible for extremely fast decarboxylation of the aroylbenzoyloxyl radicals, and we believe this could be the case. The aroyloxyl radicals are known to decarboxylate faster, leading to the formation of the aryl radicals when they absorb at either 308 or 700 nm (ref 14a). It has also been shown that the benzoyloxyl radical that has been stabilized by preparation at low temperatures (67 K) can be photodecar-boxylated with light of 550-1300 nm (Karch, N. J.; Koh, E. T.; Whitsel, B. L.; McBride, J. M. J. Am. Chem. Soc. 1975, 97, 6729).
    • (1975) J. Am. Chem. Soc. , vol.97 , pp. 6729
    • Karch, N.J.1    Koh, E.T.2    Whitsel, B.L.3    McBride, J.M.4
  • 51
    • 1242280032 scopus 로고    scopus 로고
    • note
    • -1 (the error involved in this measurement is large due to the low OD at 550 nm).
  • 52
    • 1242324786 scopus 로고    scopus 로고
    • note
    • Since the triplet states are also quenched by oxygen, the 550 nm absorption might be mistakenly assigned to the triplet state of BPs, as was done by Allen et al. (ref 6), who assigned the 550 nm absorption obtained from the nanosecond LFP of 1 in acetonitrile to its triplet state.
  • 53
    • 1242324787 scopus 로고    scopus 로고
    • note
    • The only common radical that can be obtained from both 1 and p-iodobenzophenone is the 4-benzoylphenyl radical. The similar ∼560 nm absorption observed previously during nanosecond LFP of 1 was tentatively assigned to the 4-benzoylbenzoyloxyl radical on the basis of the resemblance of its lifetime to that of the benzoyloxyl radical (ref 14). However, the lifetimes of the aroylphenyl radicals have also been found to be in a similar range (∼0.4 μs) and depend on the solvent and concentration of the precursor BPs. The evidence presented in the text clearly suggests that the 550 nm absorption is due to the aroylphenyl radicals.
  • 59
    • 85087597489 scopus 로고    scopus 로고
    • note
    • -1, respectively (ref 34a).
  • 61
    • 1242302335 scopus 로고    scopus 로고
    • note
    • We have recently measured the triplet lifetime of p-iodobenzophenone and it was found to be 98.46 ± 2.16 ps in benzene (detailed results will be published elsewhere).


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.