2,2,6,6-Tetramethylpiperidin-4-ol Singlet oxygen

Kamath, S.S.; Srivastava, T.S.
J. Photochem. Photobiol., A 52, 83-89 (1990)

Reaction: 2,2,6,6-Tetramethylpiperidin-4-ol + ¹O₂^* ® 4-Hydroxy-2,2,6,6-tetramethylpiperidine N-oxyl
Solvent: HCON(CH₃)₂

k = 5.0 × 10⁷(L mol^-1 s^-1)

Experimental method: Photolysis
Analytical method: electron spin resonance
Data type: Derived from steady state measurements

Photosensitizer = Bis(azido)(1,10-phenanthroline)platinum(II); Obs. formn. of 4-hydroxy-2,2,6,6-tetramethylpiperidine N-oxyl. [Sensitizer] = 2 × 10^-4 (mol L^-1). [O₂] = O₂.

Shukla, S.; Srivastava, T.S.
J. Photochem. Photobiol., A 48, 249-257 (1989)

Reaction: 2,2,6,6-Tetramethylpiperidin-4-ol + ¹O₂^* ® 4-Hydroxy-2,2,6,6-tetramethylpiperidine N-oxyl
Solvent: DMF

k = 5.0 × 10⁷(L mol^-1 s^-1)

Experimental method: Modulated photolysis
Analytical method: electron spin resonance
Data type: Derived from steady state measurements

Photosensitizer = Hematoporphyrin IX. used solvent k_d = 1.4 × 10⁵ s^-1. Obs. formn. of 4-hydroxy-2,2,6,6-tetramethylpiperidine N-oxyl. [Sensitizer] = 5 × 10^-5 (mol L^-1).

Alegria, A.E.; Krishna, C.M.; Elespuru, R.K.; Riesz, P.
Photochem. Photobiol. 49, 257-265 (1989)

Reaction: 2,2,6,6-Tetramethylpiperidin-4-ol + ¹O₂^* ® 4-Hydroxy-2,2,6,6-tetramethylpiperidine N-oxyl
Solvent: DMSO

k = 5.2 × 10⁶(L mol^-1 s^-1)

Experimental method: Photolysis
Analytical method: electron spin resonance
Data type: Derived from steady state measurements

Photosensitizer = Gilvocarcin V. used solvent k_d = 5.2 × 10⁴ s^-1. Obs. formn. of 4-hydroxy-2,2,6,6-tetramethylpiperidine N-oxyl.

Cen, J.; Hu, X.; Shen, D.; Zhu, L.
Ganguang Kexue Yu Kuang Huaxue, 1-8 (1988)

Reaction: 2,2,6,6-Tetramethylpiperidin-4-ol + ¹O₂^* ® products and/or physical quenching
Solvent: CHCl₃

k = 2.6 × 10⁵(L mol^-1 s^-1)

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

Photosensitizer = Indicator = Rubrene; used solvent k_d = 1.7 × 10⁴ s^-1; k for indicator = 5.3 × 10⁷ L/(mol·s).

Ballardini, R.; Beggiato, G.; Bortolus, P.; Faucitano, A.; Buttafava, A.; Gratani, F.
Polym. Degrad. Stab. 7, 41-53 (1984)

Reaction: 2,2,6,6-Tetramethylpiperidin-4-ol + ¹O₂^* ® products and/or physical quenching
Solvent: Benzene, 50%, Ethanol, 50%

k = <1.0 × 10⁵(L mol^-1 s^-1)

Experimental method: Flash photolysis
Analytical method: vis-UV absorption
Data type: Limiting value
Excitation wavelength: 694 nm

Photosensitizer = Methylene Blue; Indicator = 1,3-Diphenylisobenzofuran.

Lion, Y.; Gandin, E.; Van de Vorst, A.
Photochem. Photobiol. 31, 305-309 (1980)

Reaction: 2,2,6,6-Tetramethylpiperidin-4-ol + ¹O₂^* ® 4-Hydroxy-2,2,6,6-tetramethylpiperidine N-oxyl
Solvent: EtOH

k = 8 × 10⁵(L mol^-1 s^-1)

Experimental method: Photolysis
Analytical method: electron spin resonance
Data type: Derived from steady state measurements

Photosensitizer = Rose Bengal dianion. used solvent k_d = 8 × 10⁴ s^-1. Obs. formn. of 4-hydroxy-2,2,6,6-tetramethylpiperidine N-oxyl. [Sensitizer] = 1 × 10^-4 (mol L^-1).

Lion, Y.; Gandin, E.; Van de Vorst, A.
Photochem. Photobiol. 31, 305-309 (1980)

Reaction: 2,2,6,6-Tetramethylpiperidin-4-ol + ¹O₂^* ® 4-Hydroxy-2,2,6,6-tetramethylpiperidine N-oxyl
Solvent: H₂O

k/k_reference = 2.5 × 10^-2
k = 4 × 10⁷(L mol^-1 s^-1), k_quen = 2 × 10⁹(mol L^-1), pH = 8

Experimental method: Photolysis
Analytical method: electron spin resonance
Data type: Relative value measured by steady state method

Photosensitizer = Rose Bengal dianion; Quencher = Azide ion, k_quencher = 2 × 10⁹ L mol^-1 s^-1. Obs. formn. of 4-hydroxy-2,2,6,6-tetramethylpiperidine N-oxyl. Use Azide ion as quencher. [Sensitizer] = 1 × 10⁴ (mol L^-1).

Monroe, B.M.
J. Phys. Chem. 81, 1861-1864 (1977)

Reaction: 2,2,6,6-Tetramethylpiperidin-4-ol + ¹O₂^* ® products and/or physical quenching
Solvent: CHCl₃

k = <2.0 × 10⁵(L mol^-1 s^-1)

Experimental method: Photolysis
Analytical method: vis-UV absorption
Data type: Limiting value

Photosensitizer = Indicator = Rubrene; No measurable effect.

Ivanov, V.B.; Shlyapintokh, V.Ya.; Khvostach, O.M.; Shapiro, A.B.; Rozantsev, E.G.
J. Photochem. 4, 313-319 (1975)

Reaction: 2,2,6,6-Tetramethylpiperidin-4-ol + ¹O₂^* ® 4-Hydroxy-2,2,6,6-tetramethylpiperidine N-oxyl
Reference Reaction: Naphthalene + ¹O₂^* ®
Solvent: C₆H₆, 89%, EtOH, 11%

k_react = 2.9 × 10³(L mol^-1 s^-1), k_reference = 7 × 10⁷(L mol^-1 s^-1), T = 295K

Experimental method: Photolysis
Analytical method: electron spin resonance
Data type: Relative value measured by steady state method

Photosensitizer = Rose Bengal dianion.

Ivanov, V.B.; Shlyapintokh, V.Ya.; Khvostach, O.M.; Shapiro, A.B.; Rozantsev, E.G.
J. Photochem. 4, 313-319 (1975)

Reaction: 2,2,6,6-Tetramethylpiperidin-4-ol + ¹O₂^* ® products and/or physical quenching
Solvent: C₆H₆, 89%, EtOH, 11%

k = 5 × 10⁵(L mol^-1 s^-1), T = 295K

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

Photosensitizer = Rose Bengal dianion; used solvent k_d = 3 × 10⁴ s^-1. Indicator = Naphthalene, k for indicator = 7 × 10⁷ L/(mol·s).