Photochemistry of Fe(III)-Tetracycline Complexes in Aqueous Solution under UV Irradiation

The form and photochemistry of the Fe(III)-Tetracycline complex (Fe(III)-TC) in aqueous solution were investigated under UV-C light (254 nm) by UV-Vis spectrometry. The ratio of Fe(III) to Tetracycline (TC) in the Fe(III)-TC complex was 1: 2, as determined by Job´s method at a characteristic absorption wavelength of 440 nm. The concentration of Fe(II) produced by the photo reduction of Fe(III) species and the quantum yield of Fe(II) (Φ_Fe(II)) were determined. The photo reactivity of the Fe(III)-TC complex was higher than that of the Fe(III)-OH complex in terms of Φ_Fe(II). The photochemical production of Fe(II) decreased with increasing pH in the range 3.0-9.0.