Spectroscopic and Photophysical Properties of Terbutaline

Abstract

In this paper, we report the photophysical and spectroscopic properties of Terbutaline in different solvent and under different acidic conditions. Theoretical calculations were also used to analyze the photophysical properties. It was found that; the Terbutaline exhibits a characteristic absorption band in the range of 252-287 nm and emission bands at 302 nm and 624 nm (f_f = 0.114, τ = 14.9 ns). Solvents were found to have a significant effect on the position of the absorption and emission peaks. Moreover, solvents properties were found to strongly affect the fluorescence quantum yield were it is found that it is relatively high in polar solvents. The fluorescence intensity of the cationic species was significantly quenched in the presence of strong acids such as H₂SO₄ and HCl, although the absorption and excitation shape of peak in spectra remained unchanged. Both the steady state and time resolved fluorescence measurements show that the quenching of Terbutaline by proton is a dynamic process with quenching rate constants, kq, equals to 1.5 × 10⁸ and 1.02 × 10⁸ in sulfuric and hydrochloric acid, respectively.