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Volumn 111, Issue 7, 2007, Pages 1188-1199

Highly efficient triplet chain isomerization of Dewar benzenes: Adiabatic rate constants from cage kinetics

Author keywords

[No Author keywords available]

Indexed keywords

CHAIN PROPAGATING ENERGY TRANSFER; DEWAR BENZENE DERIVATIVES; EXOTHERMICITY; SENSITIZATION;

EID: 33847715502     PISSN: 10895639     EISSN: None     Source Type: Journal    
DOI: 10.1021/jp067485j     Document Type: Article
Times cited : (14)

References (63)
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    • 11b,c to the effect of a photoactive impurity. (a) Hyndman, H. L.; Monroe, B. M.; Hammond, G. S. J. Am. Chem. Soc. 1969, 91, 2852.
  • 18
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    • As discussed in ref 4, more complex schemes may apply for cis/trans isomerizations
    • As discussed in ref 4, more complex schemes may apply for cis/trans isomerizations.
  • 19
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    • See, for example: a, Padwa, A, Ed, Marcel Dekker: New York
    • See, for example: (a) Mattes, S. L.; Farid, S. In Organic Photochemistry; Padwa, A., Ed.; Marcel Dekker: New York, 1983; Vol. 6, p 233.
    • (1983) Organic Photochemistry , vol.6 , pp. 233
    • Mattes, S.L.1    Farid, S.2
  • 20
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    • Fox, M. A, Chanon, M, Eds, Elsevier: Amsterdam
    • (b) Lewis, F. D. In Photoinduced Electron Transfer, Fox, M. A., Chanon, M., Eds.; Elsevier: Amsterdam, 1988; Vol. C, p 1.
    • (1988) Photoinduced Electron Transfer , vol.100 , pp. 1
    • Lewis, F.D.1
  • 26
    • 33847758122 scopus 로고    scopus 로고
    • Measured vs SCE in methylene chloride by Dr. M. Madaras of Eastman Kodak Co
    • Measured vs SCE in methylene chloride by Dr. M. Madaras of Eastman Kodak Co.
  • 30
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    • S notation here for brevity.
    • S notation here for brevity.
  • 31
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    • and references therein
    • Kira, A.; Thomas J. K. J. Phys. Chem. 1974, 78, 196 and references therein.
    • (1974) J. Phys. Chem , vol.78 , pp. 196
    • Kira, A.1    Thomas, J.K.2
  • 32
    • 0000181757 scopus 로고    scopus 로고
    • While differences in entropy between the triplet and ground states (AS) are expected to be small for the relatively rigid sensitizers used in our experiments, they may not be negligible. For example, ΔS values of approximately -0.6 to -1.2, 0.2, 1.8, and -0.8 kcal/mol may be estimated at room temperature for excitation of benzophenone,23a,b 4-methylbenzophenone,23c biphenyl,23a and 4-methylbiphenyl,23c respectively, on the basis of the effect of temperature on triplet-energy-transfer equilibria, a) Gessner, F, Scaiano, J. C. J. Am. Chem. Soc. 1985, 107, 7206
    • 23c respectively, on the basis of the effect of temperature on triplet-energy-transfer equilibria. (a) Gessner, F.; Scaiano, J. C. J. Am. Chem. Soc. 1985, 107, 7206.
  • 35
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    • 24a (a) Coenjarts, C.; Scaiano, J. C. J. Am. Chem. Soc. 2000, 122, 3635.
    • 24a (a) Coenjarts, C.; Scaiano, J. C. J. Am. Chem. Soc. 2000, 122, 3635.
  • 36
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    • This is the value of kd calculated from the Smoluchowski equation (kd, 4πNrs+RDS+R/1000) with r s+R, 5.5 Å and DS+R, 2.9 × 10-5 cm2 s-1, where the diffusion coefficient DS+R is calculated from the Stokes-Einstein equation (DS+R, DS, DR, RT/6πηrSN, RT/6πηrRN) with η, 0.5 cP and rS, rR, 2.75 Å
    • R = 2.75 Å.
  • 37
    • 0003924674 scopus 로고
    • For example, the triplet energy of 2-butene is ∼10 kcal/mol higher than that of dimethyl fumarate, and the triplet energy of β-methylstyrene is ∼5 kcal/mol higher than that of methyl cinnamate.26a a, 2nd ed, Marcel Dekker: New York
    • 26a (a) Murov, S. L; Camichael, I.; Hug, G. L. Handbook of Photochemistry, 2nd ed.; Marcel Dekker: New York, 1993.
    • (1993) Handbook of Photochemistry
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    • † is nonzero is arguable. See, for example: Saltiel, J.; Marchand, G. R.; Kirkor-Kaminska, E.; Smothers, W. K.; Mueller, W. B.; Charlton, J. L. J. Am. Chem. Soc. 1984, 106, 3144.
    • † is nonzero is arguable. See, for example: Saltiel, J.; Marchand, G. R.; Kirkor-Kaminska, E.; Smothers, W. K.; Mueller, W. B.; Charlton, J. L. J. Am. Chem. Soc. 1984, 106, 3144.
  • 42
    • 33847752103 scopus 로고    scopus 로고
    • The thermodynamic triplet energy for B2 is less accurately determined due to a small amount of absorption by photoproduct(s) in the region of the sensitizer triplet transient absorption.
    • The thermodynamic triplet energy for B2 is less accurately determined due to a small amount of absorption by photoproduct(s) in the region of the sensitizer triplet transient absorption.
  • 43
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    • Quantum mechanical computations of triplet energies of benzene derivatives with bulky substituents are sparse. However, calculations on p-xylene suggest a quinoidal triplet conformation about 4.6 kcal/mol lower in energy than the vertical hexagonal form as well as an antiquinoidal conformation that is about 0.6 kcal/mol more stable than the hexagonal form. Buma, W. J, van der Waals, J. H, van Hemert, M. C. J. Chem. Phys. 1990, 93, 3746
    • Quantum mechanical computations of triplet energies of benzene derivatives with bulky substituents are sparse. However, calculations on p-xylene suggest a quinoidal triplet conformation about 4.6 kcal/mol lower in energy than the vertical hexagonal form as well as an antiquinoidal conformation that is about 0.6 kcal/mol more stable than the hexagonal form. Buma, W. J.; van der Waals, J. H.; van Hemert, M. C. J. Chem. Phys. 1990, 93, 3746.
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    • S+R = 5.5Å: Eigen, M. Z. Phys. Chem. 1954, 1, 176.
    • S+R = 5.5Å: Eigen, M. Z. Phys. Chem. 1954, 1, 176.
  • 48
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    • Although both kd and k-d decrease with increasing solvent viscosity, it is generally accepted that their ratio, k -d/kd, remains constant. See ref 34 and Pilling, M. J, Seakins, P. W. Reaction Kinetics; Oxford University Press: Oxford, 1995; pp 146-156
    • d, remains constant. See ref 34 and Pilling, M. J.; Seakins, P. W. Reaction Kinetics; Oxford University Press: Oxford, 1995; pp 146-156.
  • 49
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    • The 0-0 phosphorescence band at 77 K for DETX* occurs at about 62 kcal/mol in ethyl acetate and at about 60 kcal/mol in more polarizable chloroform.
    • The 0-0 phosphorescence band at 77 K for DETX* occurs at about 62 kcal/mol in ethyl acetate and at about 60 kcal/mol in more polarizable chloroform.
  • 50
    • 33847696410 scopus 로고    scopus 로고
    • TCE was chosen as an analogue of DB2 without the complications of chain isomerization. The short lifetime of triplet TCE eliminates reverse energy transfer as is the case for R, and the rate constants for quenching of triplet IMP are similar for TCE and DB2.
    • TCE was chosen as an analogue of DB2 without the complications of chain isomerization. The short lifetime of triplet TCE eliminates reverse energy transfer as is the case for R, and the rate constants for quenching of triplet IMP are similar for TCE and DB2.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.