US EPA

1170070 

Journal Article 

Transient absorption spectra of bifunctional probes of a chromophore-sterically hindered amine type in solution; study of the triplet route to deactivation 

Hrdlovic, P; Chmela, S; Sarakha, M; Lacoste, J 

2001 

Yes 

Journal of Photochemistry and Photobiology A: Chemistry
ISSN: 1010-6030
EISSN: 1873-2666 

ELSEVIER SCIENCE SA 

LAUSANNE 

138 

2 

95-109 

English 

10.1016/S1010-6030(00)00376-2 

WOS:000166561600002 

https://www.scopus.com/inward/record.uri?eid=2-s2.0-0009533939&doi=10.1016%2fS1010-6030%2800%2900376-2&partnerID=40&md5=d5e19d9ec3e20070e43428e08e4ccfe1
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Laser flash photolysis was used to study formation and decay of triplet states of bifunctional probes of type chromophore (naphthalene, 1,8-naphthaleneimide, pyrene)-sterically hindered amine (HAS). For all types of probes, the formation of the triplet state with absorption in the range 400-500 nm occurred after 266 nm excitation. The same triplet was formed at 355 nm excitation for probes extending absorption to this region. Tripler states of all probes were quenched by oxygen with rate constant 1-5 x 10(9) dm(3) mol(-1) cm(-1). Intermolecular quenching of triplet states of the parent probes by N-oxyl (1-oxo-2,2,6,6-tetramethyl-4-hydroxypiperidine) was effective for naphthalene type probes and practically no effective for pyrene ones. The efficiency of intramolecular quenching in oxidised probes was determined by type of chromophore. The most effective intramolecular quenching was observed for N-(1-oxo-2,2,6,6-tetramethyl-4-piperidinyl)-1,8-naphthaleneimide in methanol, (C) 2001 Elsevier Science B.V. All rights reserved. 

N-oxyl; sterically hindered amine (HAS); triplet route