Spectral and Luminescent Characteristics of a Hexaphenyltetraazachlorin Zinc Complex

Abstract

In continuation of previous studies on the photophysics of phenyl-substituted tetraazachlorins, we determined the spectral and luminescent characteristics of a tetramethylhexaphenyltetraazachlorin zinc complex at 293 and 77 K. Absorption, fluorescence, and fluorescence excitation spectra; the fluorescence quantum yield and lifetime; and the quantum yield for singlet oxygen generation were measured at room temperature. Fluorescence, fluorescence excitation, and fluorescence polarization spectra were measured at liquid nitrogen temperature. Fluorescence spectra indicated that the zinc complex rearranged in the excited electronic state S1 at both temperatures. A high quantum yield for singlet oxygen generation (0.91) was obtained for a toluene solution. Zn-tetramethylhexaphenyl tetraazachlorin was proposed as a photosensitizer for photodynamic therapy because the long-wavelength band at 707 nm was located in the transparent region of biological tissues.