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Volumn 112, Issue 2, 2008, Pages 483-494

The ultrafast charge-transfer-to-solvent dynamics of iodide in tetrahydrofuran. 1. Exploring the roles of solvent and solute electronic structure in condensed-phase charge-transfer reactions

Author keywords

[No Author keywords available]

Indexed keywords

ABSORPTION; ELECTRONIC STRUCTURE; PHASE TRANSITIONS; SOLVATION; SOLVENTS; SPECTROSCOPY;

EID: 38749153948     PISSN: 15206106     EISSN: None     Source Type: Journal    
DOI: 10.1021/jp076934s     Document Type: Article
Times cited : (32)

References (107)
  • 53
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    • The transients plotted in Figure lb were reconstructed using the fitting parameters presented in ref 2
    • The transients plotted in Figure lb were reconstructed using the fitting parameters presented in ref 2.
  • 76
    • 84906393404 scopus 로고    scopus 로고
    • - in THF.
    • - in THF.
  • 80
    • 84906379502 scopus 로고    scopus 로고
    • - spectrum, the two add to recover the measured composite.
    • - spectrum, the two add to recover the measured composite.
  • 81
    • 84906393405 scopus 로고    scopus 로고
    • - spectrum varied by only ∼1 nm, indicating that this stipulation is robust and minimally influences the value obtained.
    • - spectrum varied by only ∼1 nm, indicating that this stipulation is robust and minimally influences the value obtained.
  • 82
    • 84906393402 scopus 로고    scopus 로고
    • Figure 1c suggests that all of the transients shown in Figure 4 should reflect only the dynamics of the detached electrons, though we cannot rule out the possibility that at visible probe wavelengths, where the electron's absorption cross section is small, there may be minor contributions from a weak charge-transfer-from-solvent (CTFS) band associated with nascent neutral iodine.8,102 We note, however, that the population kinetics of the two must be identical according to the stoichiometry for geminate recombination: I, eTHF- → I, Because we would expect there to be a significant amount of dynamic solvation of the newly formed I atom as there is for the neutral sodium atom left behind following the CTTS excitation of Na, 21,22 the fact that we observe identical kinetics at 650 nm and in the IR suggests that absorption due to the CTFS band of I is negligible at this probe wavelength
    • 21,22 the fact that we observe identical kinetics at 650 nm and in the IR suggests that absorption due to the CTFS band of I is negligible at this probe wavelength.
  • 83
    • 84906365142 scopus 로고    scopus 로고
    • The wavelength independence of these measured transients throughout the visible and infrared also indicates the absence of any type of transformation of the solvated electrons between cavity- and valence-bound motifs, 103,104 as has been observed in solution following CTTS excitation of I- in acetonitrile.28
    • 28
  • 88
    • 0003010968 scopus 로고
    • Diffusion-Limited Reactions
    • Elsevier: Amsterdam, The Netherlands
    • Rice, S. A. Diffusion-Limited Reactions. Chemical Kinetics; Elsevier: Amsterdam, The Netherlands, 1985; Vol. 25.
    • (1985) Chemical Kinetics , vol.25
    • Rice, S.A.1
  • 90
    • 84906379501 scopus 로고    scopus 로고
    • B is Boltzmann's constant.
    • B is Boltzmann's constant.
  • 91
    • 84906393399 scopus 로고    scopus 로고
    • Even if we assume that the relative diffusion is dominated entirely by the electron, the data in Figure 5b are still well-fit with a 10 Å reaction radius, which corresponds to ∼2 solvent shells in THF.
    • Even if we assume that the relative diffusion is dominated entirely by the electron, the data in Figure 5b are still well-fit with a 10 Å reaction radius, which corresponds to ∼2 solvent shells in THF.
  • 92
    • 84906365141 scopus 로고    scopus 로고
    • We note that Barbara and co-workers were able to use this model to extract the size-dependent scavenging rates of various excited states of the eH2O- 85 because the electronic radii were known from independent measurements.86
    • 86
  • 93
    • 84906393400 scopus 로고    scopus 로고
    • Binary solution environments do introduce the possibility of preferential ion solvation.38 For the solutions used in these scavenging experiments, preferential solvation of I- by chloroform could result in a substantial scavenging enhancement. We note that we could not measure an observable shift in the I- CTTS spectrum with the addition of chloroform at the highest concentration used in scavenging experiments (∼1, mole fraction, which suggests that the chloroform negligibly influences the immediate environment of the CTTS anion. Furthermore, we anticipate that dynamic scavenging highlighted in Figure 5b would not exhibit kinetics consistent with a diffusion model using the (homogenous) bulk scavenger concentration if a significant concentration enhancement near I- existed. Also, we expect that the measured static scavenging yield would have a steep onset at low concentrations if there were strong I--chloroform interactions
    • sc. Therefore, we anticipate that any local concentration enhancement should not appreciably affect the nanometer size of the excited-state distribution obtained from this analysis.
  • 94
    • 84906379498 scopus 로고    scopus 로고
    • There is some evidence that suggests that the THF radical cation undergoes rapid chemistry with neighboring THF molecules subsequent to MPI,14 such that the electron may recombine with a molecule that was not the original parent, as is the case for the multiphoton ionization of water. 106,107
    • 106,107
  • 101
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    • Private communication
    • Bradforth, S. E. Private communication.
    • Bradforth, S.E.1


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.