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Volumn 129, Issue 19, 2007, Pages 6255-6262

The solvent cage effect: Is there a spin barrier to recombination of transition metal radicals?

Author keywords

[No Author keywords available]

Indexed keywords

ABSORPTION SPECTROSCOPY; BENZENE; PHOTOLYSIS; QUANTUM YIELD; REACTION KINETICS; SOLVENTS; SPIN DYNAMICS;

EID: 34249097387     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja069295s     Document Type: Article
Times cited : (23)

References (96)
  • 7
    • 34249093423 scopus 로고    scopus 로고
    • Cage effects are necessary to explain a host of kinetic observations and fundamental reaction phenomena. Examples of important reactions where cage effects are necessary to explain the kinetics include radical polymerization reactions,8-12 the reactions of coenzyme B12 and its model complexes,13-17 the reactions of hemes with O2, 18 the reactions of photosynthetic model complexes, and numerous electron transfer reactions.19.20 The literature is replete with new observations of the cage effect and its impact on reactivity. For example, the repercussions of cage effects in confined media such as micelles and zeolites,21-25 biochemical toxicity,26 supercritical fluids,27 polymer degradation reactions,28-31 chemiluminescence,32-34 bond cleavage energetics,35 and in metal complex photochemistry36 are areas of current study. Furthermore, cage effects
    • 48-51
  • 52
    • 34249086104 scopus 로고    scopus 로고
    • In addition to recombination and diffusive separation, the chemical reactions of cage pairs can include disproportionation, isomerizations, fragmentations, electron transfer, in-cage trapping, etc. For the metal-radical cage pairs in this paper, the only chemical process is kc
    • In addition to recombination and diffusive separation, the chemical reactions of cage pairs can include disproportionation, isomerizations, fragmentations, electron transfer, in-cage trapping, etc. For the metal-radical cage pairs in this paper, the only chemical process is kc.
  • 56
    • 0002446121 scopus 로고
    • Wiley: New York
    • Ingold, K. U. In Free Radicals; Wiley: New York, 1973; Vol. 1, pp 37-112.
    • (1973) Free Radicals , vol.1 , pp. 37-112
    • Ingold, K.U.1
  • 93
    • 34249076474 scopus 로고    scopus 로고
    • A reviewer points out that it is conceivable that bromine or other heavy atoms could result in a heavy atom effect in coumarin but not in a transition metal radical cage pair. Specifically, this situation could result if the rate enhancement caused by the heavy atom is comparable to (or faster than) the ISC rate in coumarin but slower than the ISC rate in the transition metal radical cage pair. As shown in the next section, the transition metal cage pairs recombine on the timescale of 5 ps. The timescale of ISC in the transition metal cage pair would thus have to be shorter than 5 ps for this situation to apply. In any case, a radical-radical recombination reaction with a 5 ps timescale would not traditionally be considered to have a spin barrier
    • A reviewer points out that it is conceivable that bromine or other heavy atoms could result in a heavy atom effect in coumarin but not in a transition metal radical cage pair. Specifically, this situation could result if the rate enhancement caused by the heavy atom is comparable to (or faster than) the ISC rate in coumarin but slower than the ISC rate in the transition metal radical cage pair. As shown in the next section, the transition metal cage pairs recombine on the timescale of 5 ps. The timescale of ISC in the transition metal cage pair would thus have to be shorter than 5 ps for this situation to apply. In any case, a radical-radical recombination reaction with a 5 ps timescale would not traditionally be considered to have a spin barrier.
  • 94
    • 34249072962 scopus 로고    scopus 로고
    • The choice of a suitable heavy-atom-containing molecule for use in pump-probe experiments required that the compound be inert toward reaction with the transient radical species, that it not absorb at wavelengths used in the study, and that it has minimal second- and third-order non-linear optical susceptibility coefficients, χ(2) and χ3, to eliminate artifacts that would obscure the results
    • (3), to eliminate artifacts that would obscure the results.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.