Fluorescence quenching dynamics of azulene and 2-haloazulenes by CCl4 in nonpolar solvents

Abstract

On the basis of picosecond fluorescence lifetime measurements, we report the fluorescence quenching dynamics of azulene and 2-haloazulenes (halogen=Cl, Br, and I) in cyclohexane by CCl4 in the S2 electronic state. It has been observed that azulene fluorescence is efficiently quenched by carbon tetrachloride with a diffusion-limited rate constant of 8.1×109 M-1 s-1, while 2-haloazulenes do not show fluorescence quenching by CCl4.