ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Spectral Characteristics of Bifunctional Fluorescence Probes Based on Naphthalene: Comparison in Solution and Polymer Matrix

P. Hrdlovič, Š. Chmela, and Ľ. Bucsiová

Polymer Institute, Slovak Academy of Sciences, SK-842 36 Bratislava

Abstract: Spectral properties of bifunctional fluorescence probes of esters of 1-naphthoic and 1-naphthylacetic acids with methanol, 2,2,6,6-tetramethyl-4-hydroxypiperidine, its N-oxyl and chloride in solution and in polymer matrix were studied. Esters of 1-naphthoic acid exhibit broad absorption and emission bands which shift bathochromically in going from nonpolar to polar solvents. Esters of 1-naphthylacetic acid exhibit absorption spectrum typical for naphthalene chromophore which is not influenced by the polarity of solvent or polymer matrix. The different spectral behaviour of derivatives of 1-naphthylacetic and 1-naphthoic acids stresses the role of methylene bridge between the naphthyl ring and ester group in esters of 1-naphthylacetic acid whereas there is the direct interaction in the esters of 1-naphthoic acid. The fluorescence lifetime of esters of 1-naphthoic acid is in the range of 2-4 ns and it decays as monoexponential with some approximation. Intermolecular quenching of esters of 1-naphthoic acid by N-oxyls is effective and occurs as a diffusion-controlled process. Intramolecular quenching, which proceeds in N-oxyls derived from esters of 1-naphthoic and 1-naphthylacetic acids, is equally effective in solution and in polymer matrices. Small medium effect on intramolecular quenching supports the conclusion that the new radiationless channel is opened in the presence of paramagnetic centre for dissipation of electronic energy.

Full paper in Portable Document Format: 505a271.pdf

Chemical Papers 50 (5) 271–278 (1996)