Photophysical and photochemical deactivation processes of ultraviolet stabilizers of the (2-hydroxyphenyl)benzotriazole class

Woessner, Gottfried; Goeller, Gernot; Kollat, P.; Stezowski, John J.; Hauser, Manfred; Klein, U.; Kramer, Horst E. A.

doi:10.1021/j150667a017

Cited by 90 publications

(74 citation statements)

References 4 publications

(4 reference statements)

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“…The red emission observed at room temperature in non-polar solutions of TINSi is comparable to that observed for HPBs at low temperature, [8,11,12] in mixed crystals and in pure crystalline form, [13,19] in polymers [27±29] and, more recently, in solutions at room temperature. [17,18,30] It can therefore be attributed to the keto form of TINSi.…”

Section: Discussionsupporting

confidence: 70%

Excited‐State Intramolecular Proton Transfer (ESIPT) and Energy Relaxation Processes in Hydroxyphenylbenzotriazole Derivatives: A Femtosecond Laser Study

et al. 2001

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Section: Discussionsupporting

confidence: 70%

Excited‐State Intramolecular Proton Transfer (ESIPT) and Energy Relaxation Processes in Hydroxyphenylbenzotriazole Derivatives: A Femtosecond Laser Study

et al. 2001

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“…This mechanism is illustrated in Scheme 1. The excited singlet state is capable of relaxing within ∼100 fs, via adiabatic transfer of the phenolic proton to the nitrogen of the triazole ring producing isomer K. 13 The excited state isomer K, shows very weak red shifted fluorescence under special conditions; 4,9,11,[14][15][16][17][18] however, subpicosecond internal conversion 13 from the excited "keto" form is the strongly favored process. 9 The ESIPT mechanism has definite conformational requirements, the most important of which is a planar conformation (closed form) that is capable of producing an intramolecular hydrogen bond in the ground state.…”

Section: Introductionmentioning

confidence: 99%

Twisted Intramolecular Charge Transfer States in 2-Arylbenzotriazoles: Fluorescence Deactivation via Intramolecular Electron Transfer Rather Than Proton Transfer

et al. 2002

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Ultraviolet absorbers such as Tinuvin P (2-(2-hydroxy-5-methylphenyl)benzotriazole), 1, achieve their exceptional photostabilities as a result of deactivation of excited singlet states through excited state intramolecular proton transfer (ESIPT). Adding a methyl group to the 6′ position of 2-arylbenzotriazoles reveals an additional excited singlet state deactivation mechanism in this class of molecules which does not require intramolecular hydrogen bonding. Steady state fluorescence and fluorescence lifetime measurements for a series of 6′-methyl-2-arylbenzotriazoles provides compelling evidence for a twisted intramolecular charge transfer (TICT) mechanism of excited singlet state deactivation. Due to the steric requirements of the 6′-methyl group, conformations are favored in which the phenyl and triazole rings are no longer coplanar. In the case of compound 11 (2-(6-methoxy-2,3-dimethylphenyl)-2H-benzotriazole), the presence of a 2′-methoxy group enhances nonplanarity and results in large deactivation rates. Compound 12 (2-(6-methoxy-2,3-dimethylphenyl)-5-(trifluoromethyl)-2H-benzotriazole), which possesses both twist and enhanced donor/acceptor properties, undergoes the most efficient fluorescence quenching for the methoxyarylbenzotriazoles. Compounds with both a 6′-methyl and a hydroxy group on the phenyl ring exhibit diffusion controlled quenching (k q ) 2 × 10 10 M -1 s -1) by DMSO. This quenching appears to result from either partial or complete excited state proton transfer to DMSO, which enhances TICT deactivation of the singlet excited state.

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“…Extensive studies on photochemical and photophysical properties of molecules showing excited state intramolecular proton transfer (ESIPT), such as o ‐hydroxybenzophenones [8–11], methylsalicylates [12–17], 2‐(2′‐hydroxyaryl)‐benzotriazoles [18–21] and 2‐(2′‐hydroxyaryl)‐1,3,5‐triazines [22, 30, 31] have been performed. It is accepted that the presence of strong intramolecular hydrogen bond (IMHB) in the compounds mentioned above ensures increased photostability.…”

Section: Introductionmentioning

confidence: 99%

2‐Acetylindan‐1,3‐dione and its Cu²⁺ and Zn²⁺ complexes as promising sunscreen agents

Ahmedova

Mantareva

Enchev

et al. 2002

Intern J of Cosmetic Sci

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In continuation of a previous spectroscopic and quantum chemical study on 2-acetylindan-1,3-dione (2AID), the spectral properties and photostability of 2AID and its Cu(2+) and Zn(2+) complexes in different solvents are reported. Comparison is made with the photostability of two commercially available sunscreens: benzophenone-3 and octylmethoxycinnamate. 2AID exhibits a higher photostability, high molar absorption coefficient (42 000 m(-1) cm(-1)) at lambda(max) and broad-spectrum UV-protection properties. The hypothesis that the strong intramolecular H-bonding is responsible for the higher photostability was confirmed by studying the photodegradation upon irradiation with UV light of 2AID in hydrogen bond-breaking solvent, DMSO. The data obtained show that 2AID undergoes rapid degradation in this solvent. It is found that Cu(2+) and Zn(2+)-2AID complexes show higher photostability in DMSO than 2AID itself.

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Photophysical and photochemical deactivation processes of ultraviolet stabilizers of the (2-hydroxyphenyl)benzotriazole class

Cited by 90 publications

References 4 publications

Excited‐State Intramolecular Proton Transfer (ESIPT) and Energy Relaxation Processes in Hydroxyphenylbenzotriazole Derivatives: A Femtosecond Laser Study

Excited‐State Intramolecular Proton Transfer (ESIPT) and Energy Relaxation Processes in Hydroxyphenylbenzotriazole Derivatives: A Femtosecond Laser Study

Twisted Intramolecular Charge Transfer States in 2-Arylbenzotriazoles: Fluorescence Deactivation via Intramolecular Electron Transfer Rather Than Proton Transfer

2‐Acetylindan‐1,3‐dione and its Cu²⁺ and Zn²⁺ complexes as promising sunscreen agents

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Photophysical and photochemical deactivation processes of ultraviolet stabilizers of the (2-hydroxyphenyl)benzotriazole class

Cited by 90 publications

References 4 publications

Excited‐State Intramolecular Proton Transfer (ESIPT) and Energy Relaxation Processes in Hydroxyphenylbenzotriazole Derivatives: A Femtosecond Laser Study

Excited‐State Intramolecular Proton Transfer (ESIPT) and Energy Relaxation Processes in Hydroxyphenylbenzotriazole Derivatives: A Femtosecond Laser Study

Twisted Intramolecular Charge Transfer States in 2-Arylbenzotriazoles: Fluorescence Deactivation via Intramolecular Electron Transfer Rather Than Proton Transfer

2‐Acetylindan‐1,3‐dione and its Cu2+ and Zn2+ complexes as promising sunscreen agents

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2‐Acetylindan‐1,3‐dione and its Cu²⁺ and Zn²⁺ complexes as promising sunscreen agents