a-Tocopherol Singlet oxygen

Costantini, C.; d'Ischia, M.; Napolitano, A.; Misuraca, G.; Prota, G.
Biochim. Biophys. Acta 1116, 291-296 (1992)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: EtOH

b = 3.3(mol L^-1), T = 298K

Experimental method: Photolysis
Analytical method: HPLC
Data type: Derived from steady state measurements

Photosensitizer = 8-Methoxypsoralen; meas. k_d/k = 3.3 × 10^-3 mol/L.

Lichszteld, K.; Michalska, T.; Kruk, I.
Z. Phys. Chem. (Munich) 175, 117-122 (1992)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Reference Reaction: 2,2,6,6-Tetramethylpiperidine + ¹O₂^* ®
Solvent: MeOH

k = 4.5 × 10⁸(L mol^-1 s^-1), T = 297K

Experimental method: Chemical reaction
Analytical method: electron spin resonance
Data type: Derived from steady state measurements using indicator

Indicator = 2,2,6,6-Tetramethylpiperidine; k_d not given; soln. cont. MeONa and CoCl₂, ¹O₂* from autoxidation of adrenaline.

Kruk, I.; Lichszteld, K.; Michalska, T.; Paraskevas, S.M.
Toxicol. Environ. Chem. 35, 167-173 (1992)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: MeOH, 95%, H₂O, 5%

k = 2.6 × 10⁹(L mol^-1 s^-1), T = 310K

Experimental method: Chemical reaction
Analytical method: infrared luminescence
Data type: Derived from steady state measurements

soln. cont. 0.05 mol L^-1 MeONa and 5 × 10^-4 mol L^-1 CoCl₂, used solvent k_d = 1.8 × 10⁵ s^-1; ¹O₂* from autoxidation of oxytetracycline.

Jung, M.Y.; Choe, E.; Min, D.B.
J. Food Sci. 56, 807-810 (1991)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Reference Reaction: Soybean oil + ¹O₂^* ®
Solvent: CH₂Cl₂

k/k_reference = 261
k = 2.7 × 10⁷(L mol^-1 s^-1), k_reference = 1.0 × 10⁵(L mol^-1 s^-1), T = 298K

Experimental method: Photolysis
Analytical method: chemical analysis
Data type: Relative value measured by steady state method

Photosensitizer = Chlorophyll a; measured peroxide formation. [Sensitizer] = 3.3 × 10^-9 (mol L^-1). [Indicator] = 1.6 × 10^-1 (mol L^-1).

Mukai, K.; Daifuku, K.; Okabe, K.; Tanigaki, T.; Inoue, K.
J. Org. Chem. 56, 4188-4192 (1991)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: EtOH

k = 2.1 × 10⁸(L mol^-1 s^-1), T = 308K

Experimental method: Chemical reaction
Analytical method: vis-UV absorption
Data type: Derived from steady state measurements using indicator

Indicator = 1,3-Diphenylisobenzofuran; used solvent k_d = 8.3 × 10⁴ s^-1; ¹O₂* from MNPO₂. [Indicator] = 4.3 × 10^-5 (mol L^-1).

Shiozaki, H.; Nakazumi, H.; Takamura, Y.; Kitao, T.
Bull. Chem. Soc. Jpn. 63, 2653-2658 (1990)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: C₆H₆

k = 1 × 10⁸(L mol^-1 s^-1), k_react = 2.1 × 10⁶(L mol^-1 s^-1), k_quen = 1.4 × 10⁸(mol L^-1), T = 298K

Experimental method: Photolysis
Analytical method: vis-UV absorption
Data type: Derived from steady state measurements using indicator
Excitation wavelength: 525 nm

Photosensitizer = Indicator = Rubrene; k for indicator = 4.2 × 10⁷ L/(mol·s); used solvent k_d = 4.2 × 10⁴ s^-1; k_prod = 2.1 × 10⁶ L/(mol·s). [Sensitizer] = 1 × 10^-4 (mol L^-1).

Kaiser, S.; Di Mascio, P.; Murphy, M.E.; Sies, H.
Arch. Biochem. Biophys. 277, 101-108 (1990)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: CHCl₃, 50%, EtOH, 50%

k = 2.8 × 10⁸(L mol^-1 s^-1), T = 310K

Experimental method: Chemical reaction
Analytical method: infrared luminescence
Data type: Derived from steady state measurements

used solvent k_d = 1 × 10⁵ s^-1; ¹O₂* from NDPO₂.

Kaiser, S.; Di Mascio, P.; Murphy, M.E.; Sies, H.
Arch. Biochem. Biophys. 277, 101-108 (1990)

Reaction: a-Tocopherol + ¹O₂^* ® products
Solvent: CHCl₃, 50%, EtOH, 50%

k_react = 3.6 × 10⁶(L mol^-1 s^-1), T = 310K

Experimental method: Chemical reaction
Analytical method: HPLC
Data type: Derived from steady state measurements

used solvent k_d = 1 × 10⁵ s^-1; ¹O₂* from NDPO₂.

Kaiser, S.; Di Mascio, P.; Murphy, M.E.; Sies, H.
Arch. Biochem. Biophys. 277, 101-108 (1990)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: D₂O, 50%, EtOH, 50%

k = 4.5 × 10⁸(L mol^-1 s^-1), T = 310K

Experimental method: Chemical reaction
Analytical method: infrared luminescence
Data type: Derived from steady state measurements

used solvent k_d = 1 × 10⁵ s^-1; ¹O₂* from NDPO₂.

Neely, W.C.; Martin, J.M.; Barker, S.A.
Photochem. Photobiol. 48, 423-428 (1988)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: n-C₁₆H₃₄

k = 4.2 × 10⁷(L mol^-1 s^-1), T = 298K

Experimental method: Discharge
Analytical method: vis-UV absorption
Data type: Derived from steady state measurements using indicator

Indicator = Rubrene; k for indicator = 7.3 × 10⁷ L/(mol·s). used solvent k_d = 9 × 10⁴ s^-1.

Lang, J.; Shi, J.; Li, G.
Huadong Huagong Xueyuan Xuebao 14, 65-70 (1988)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: Methanol

k = 3.8 × 10⁸(L mol^-1 s^-1), b = 4.8 × 10^-4(mol L^-1)

Experimental method: Photolysis
Analytical method: vis-UV emission
Data type: Derived from steady state measurements using indicator

Photosensitizer = Rose Bengal dianion; used solvent k_d = 1.8 × 10⁵ s^-1; Indicator = 1,3-Diphenylisobenzofuran.

Adam, F.; Schwider, P.
Stud. Biophys. 109, 95-100 (1985)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: CCl₄

k = 5.2 × 10⁷(L mol^-1 s^-1)

Experimental method: Photolysis
Analytical method: infrared luminescence
Data type: Derived from steady state measurements

Photosensitizer = 5,10,15,20-Tetraphenylporphine. used solvent k_d = 1 × 10³ s^-1.

Gorman, A.A.; Gould, I.R.; Hamblett, I.; Standen, M.C.
J. Am. Chem. Soc. 106, 6956-6959 (1984)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: Cyclohexane

k = 8.4 × 10⁷(L mol^-1 s^-1)

Experimental method: Flash photolysis
Analytical method: vis-UV absorption
Data type: Absolute value measured directly using indicator

Photosensitizer = 2'-Acetonaphthone; Indicator = 1,3-Diphenylisobenzofuran.

Gorman, A.A.; Gould, I.R.; Hamblett, I.; Standen, M.C.
J. Am. Chem. Soc. 106, 6956-6959 (1984)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: Toluene

Enthalpy of activation = -14(kJ mol^-1), Entropy of activation = -138(J K^-1 mol^-1), Temperature range 230 to 385 K
k = 2.2 × 10⁸(L mol^-1 s^-1)

Experimental method: Flash photolysis
Analytical method: vis-UV absorption
Data type: Absolute value measured directly using indicator

Photosensitizer = 2'-Acetonaphthone; Indicator = 1,3-Diphenylisobenzofuran.

Gorman, A.A.; Gould, I.R.; Hamblett, I.; Standen, M.C.
J. Am. Chem. Soc. 106, 6956-6959 (1984)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: Acetonitrile

Enthalpy of activation = -11(kJ mol^-1), Entropy of activation = -138(J K^-1 mol^-1), Temperature range 230 to 357 K
k = 5.9 × 10⁸(L mol^-1 s^-1)

Experimental method: Flash photolysis
Analytical method: vis-UV absorption
Data type: Absolute value measured directly using indicator

Photosensitizer = 2'-Acetonaphthone; Indicator = 1,3-Diphenylisobenzofuran.

Gorman, A.A.; Gould, I.R.; Hamblett, I.; Standen, M.C.
J. Am. Chem. Soc. 106, 6956-6959 (1984)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: Acetone

Enthalpy of activation = -12(kJ mol^-1), Entropy of activation = -122(J K^-1 mol^-1), Temperature range 250 to 328 K
k = 4.3 × 10⁸(L mol^-1 s^-1)

Experimental method: Flash photolysis
Analytical method: vis-UV absorption
Data type: Absolute value measured directly using indicator

Photosensitizer = 2'-Acetonaphthone; Indicator = 1,3-Diphenylisobenzofuran.

Tanielian, C.; Mechin, R.; Esch, M.
Oxygen Radicals Chem. Biol., W. Bors, M. Saran and D. Tait (eds.), de Gruyter, Berlin, Fed. Rep. Germany, Pub. 1984, p.527-30

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: CHCl₃

k = 1.1 × 10⁸(L mol^-1 s^-1)

Experimental method: Photolysis
Analytical method: vis-UV emission
Data type: Derived from steady state measurements using indicator

Photosensitizer = Methylene Blue; Indicator = 1,3-Diphenylisobenzofuran. used solvent k_d = 4.4 × 10³ s^-1. Added solute 10^-6. [Sensitizer] = 2.5 × 10^-6 (mol L^-1). [Indicator] = 5 × 10⁵ (mol L^-1).

Gorman, A.A.; Gould, I.R.; Hamblett, I.; Standen, M.C.
J. Am. Chem. Soc. 106, 6956-6959 (1984)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: Methanol

Enthalpy of activation = -8(kJ mol^-1), Entropy of activation = -109(J K^-1 mol^-1), Temperature range 250 to 328 K
k = 3.0 × 10⁸(L mol^-1 s^-1)

Experimental method: Flash photolysis
Analytical method: vis-UV absorption
Data type: Absolute value measured directly using indicator

Photosensitizer = 2'-Acetonaphthone; Indicator = 1,3-Diphenylisobenzofuran.

Stevens, B.; Marsh, K.L.
J. Phys. Chem. 86, 4473-4476 (1982)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: Freon 113

k = 3 × 10⁷(L mol^-1 s^-1), T = 298K

Experimental method: Flash photolysis
Analytical method: infrared luminescence
Data type: Absolute value measured directly

Photosensitizer = Perylene.

Krasnovsky, A.A.,Jr.
Photochem. Photobiol. 29, 29-36 (1979)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: CCl₄

k = 1 × 10⁸(L mol^-1 s^-1)

Experimental method: Modulated photolysis
Analytical method: infrared luminescence
Data type: Derived from steady state measurements

Photosensitizer = Protoporphyrin, Tetraphenylporphine, Pheophytin a or Bacteriopheophytin A; used solvent k_d = 36 s^-1; see also [78KRA/VEN].

Krasnovsky, A.A.,Jr.; Kagan, V.E.
FEBS Lett. 108, 152-154 (1979)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: CCl₄

k = 10⁸(L mol^-1 s^-1)

Experimental method: Modulated photolysis
Analytical method: infrared luminescence
Data type: Derived from steady state measurements
Excitation wavelength: 385 nm

Photosensitizer = (all-E)-Retinal; used solvent k_d = 36 s^-1; see also [78KRA/KAG]. [Sensitizer] = £10^-6 (mol L^-1).

Gorman, A.A.; Rodgers, M.A.J.
Chem. Phys. Lett. 55, 52-54 (1978)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: D₂O (mic)

k = 6.4 × 10⁸(L mol^-1 s^-1)

Experimental method: Flash photolysis
Analytical method: vis-UV absorption
Data type: Absolute value measured directly using indicator
Excitation wavelength: 337 nm

Photosensitizer = 2'-Acetonaphthone; Indicator = 1,3-Diphenylisobenzofuran; 0.1 mol L^-1 SDS.

Koka, P.; Song, P.-S.
Photochem. Photobiol. 28, 509-515 (1978)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Reference Reaction: Chlorophyll a + ¹O₂^* ®
Solvent: EtOH

k = 1 × 10⁸(L mol^-1 s^-1)

Experimental method: Photolysis
Analytical method: vis-UV absorption
Data type: Derived from steady state measurements

Photosensitizer = Rose Bengal dianion. used solvent k_d = 1 × 10⁵ s^-1.

Yamauchi, R.; Matsushita, S.
Agric. Biol. Chem. 41, 1425-1430 (1977)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: EtOH

k = 2.6 × 10⁸(L mol^-1 s^-1), b = 3.2 × 10^-4(mol L^-1), T = 293K

Experimental method: Photolysis
Analytical method: chemical analysis
Data type: Derived from steady state measurements using indicator

Photosensitizer = Methylene Blue; used solvent k_d = 8.3 × 10⁴ s^-1; Indicator = Methyl linoleate, obs. formn. of Methyl linoleate hydroperoxide.

Yamauchi, R.; Matsushita, S.
Agric. Biol. Chem. 41, 1425-1430 (1977)

Reaction: a-Tocopherol + ¹O₂^* ® products
Solvent: EtOH

k/k_reference = 91
k_react = 6.6 × 10⁶(L mol^-1 s^-1), k_reference = 7.3 × 10⁴(L mol^-1 s^-1), T = 293K

Experimental method: Photolysis
Analytical method: chemical analysis
Data type: Relative value measured by steady state method
Indicator = Methyl linoleate

Photosensitizer = Methylene Blue.

Stevens, B.; Small, R.D.,Jr.; Perez, S.R.
Photochem. Photobiol. 20, 515-517 (1974)

Reaction: a-Tocopherol + ¹O₂^* ® products
Reference Reaction: 9,10-Diphenylanthracene + ¹O₂^* ®
Solvent: Cyclohexane

k/k_reference = 9 × 10^-1
k_react = 1.1 × 10⁶(L mol^-1 s^-1), k_reference = 1.2 × 10⁶(L mol^-1 s^-1), T = 298K

Experimental method: Photolysis
Analytical method: vis-UV absorption
Data type: Relative value measured by steady state method

Photosensitizer = 9,10-Diphenylanthracene.

Stevens, B.; Small, R.D.,Jr.; Perez, S.R.
Photochem. Photobiol. 20, 515-517 (1974)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: Cyclohexane

k = 9.0 × 10⁷(L mol^-1 s^-1), b = 6.8 × 10^-4(mol L^-1), b_ref = 1.4 × 10^-3(mol L^-1), T = 298K

Experimental method: Photolysis
Analytical method: vis-UV absorption
Data type: Derived from steady state measurements using indicator

Photosensitizer = Indicator = Rubrene. used solvent k_d = 5.9 × 10⁴ s^-1.

Fahrenholtz, S.R.; Doleiden, F.H.; Trozzolo, A.M.; Lamola, A.A.
Photochem. Photobiol. 20, 505-509 (1974)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: C₅H₅N

k = 2.5 × 10⁸(L mol^-1 s^-1)

Experimental method: Modulated photolysis
Analytical method: vis-UV absorption
Data type: Derived from steady state measurements using indicator

Photosensitizer = Indicator = Rubrene; used solvent k_d = 6.0 × 10⁴ s^-1; k for indicator = 4 × 10⁷ L/(mol·s).

Fahrenholtz, S.R.; Doleiden, F.H.; Trozzolo, A.M.; Lamola, A.A.
Photochem. Photobiol. 20, 505-509 (1974)

Reaction: a-Tocopherol + ¹O₂^* ® products
Solvent: C₅H₅N

k_react = 2.1 × 10⁶(L mol^-1 s^-1), b_ref = 9 × 10^-1(mol L^-1)

Experimental method: Modulated photolysis
Analytical method: tracer
Data type: Derived from steady state measurements

Photosensitizer = Protoporphyrin IX; Actinometer = Cholesterol; used k_total = 2.5 × 10⁸ L mol^-1 s^-1.

Stevens, B.; Small, R.D.,Jr.; Perez, S.R.
Photochem. Photobiol. 20, 515-517 (1974)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: C₆H₆

k = 1.7 × 10⁸(L mol^-1 s^-1), b = 2.7 × 10^-4(mol L^-1), b_ref = 1.0 × 10^-3(mol L^-1), T = 298K

Experimental method: Photolysis
Analytical method: vis-UV absorption
Data type: Derived from steady state measurements using indicator

Photosensitizer = Indicator = Rubrene. used solvent k_d = 4.2 × 10⁴ s^-1.

Foote, C.S.; Ching, T.-Y.; Geller, G.G.
Photochem. Photobiol. 20, 511-513 (1974)

Reaction: a-Tocopherol + ¹O₂^* ® products
Reference Reaction: 2,5-Diphenylfuran + ¹O₂^* ®
Solvent: MeOH

k/k_reference = 2.9 × 10^-1
k_react = 5 × 10⁷(L mol^-1 s^-1), k_reference = 1.6 × 10⁸(L mol^-1 s^-1)

Experimental method: Photolysis
Analytical method: vis-UV emission
Data type: Relative value measured by steady state method

Photosensitizer = Methylene Blue.

Foote, C.S.; Ching, T.-Y.; Geller, G.G.
Photochem. Photobiol. 20, 511-513 (1974)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: MeOH

k = 6.7 × 10⁸(L mol^-1 s^-1), b = 2.1 × 10^-4(mol L^-1)

Experimental method: Photolysis
Analytical method: vis-UV emission
Data type: Derived from steady state measurements using indicator

Photosensitizer = Methylene Blue; Indicator = 1,3-Diphenylisobenzofuran. used solvent k_d = 1.4 × 10⁵ s^-1.

Fahrenholtz, S.R.; Doleiden, F.H.; Trozzolo, A.M.; Lamola, A.A.
Photochem. Photobiol. 20, 505-509 (1974)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: Isooctane

k = 1 × 10⁸(L mol^-1 s^-1)

Experimental method: Modulated photolysis
Analytical method: vis-UV absorption
Data type: Derived from steady state measurements using indicator

Photosensitizer = Indicator = Rubrene; k for indicator = 4 × 10⁷ L/(mol·s); k_d not given.

Grams, G.W.; Eskins, K.
Biochemistry 11, 606-608 (1972)

Reaction: a-Tocopherol + ¹O₂^* ® products and/or physical quenching
Solvent: MeOH

k = 1 × 10⁹(L mol^-1 s^-1), b = 1 × 10^-4(mol L^-1), T = 298K

Experimental method: Photolysis
Analytical method: chemical analysis
Data type: Derived from steady state measurements

Photosensitizer = Methylene Blue; used solvent k_d = 1 × 10⁵ s^-1.