ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Quenching of aromatic triplet by monomeric and polymeric radicals in polymer film at 77 K
Š. Chmela and P. Hrdlovič
Polymer Institute, Centre for Chemical Research,
Slovak Academy of Sciences, CS-842 36 Bratislava
Abstract: The quenching of triphenylene phosphorescence by monomeric, dimeric or
polymeric radicals in poly(methyl methacrylate) film was investigated at 77 K.
The low-molecular N-oxyl radicals (11 types) were prepared by oxidation of
parent sterically hindered amines. The phosphorescence of triphenylene in
solid matrix is influenced by the type of matrix, concentration of triphenylene,
and traces of the solvents which have been used for the preparations of films.
The values of active spheres of quenching for monomeric N-oxyl radicals were
in the interval 〈1.7 nm; 2.1 nm〉 while no correlation between the size of active
sphere and change in radical structure could be observed outside the
paramagnetic centre. In a given system, the biradical exhibited quenching
efficiency which was merely slightly greater than that of monoradical. As for
polymeric radical, only small fraction (about 5 mole %) of the present
paramagnetic centres was effective as quencher, which corresponds to molecular dimensions.
For quenching of triphenylene by N-oxyl radicals in film, the parameter
γ=15 was determined.
Full paper in Portable Document Format: 382a199.pdf
Chemical Papers 38 (2) 199–215 (1984)
Tuesday, October 04, 2022