Dual Fluorescence of 10-Hydroxi Acridine(1,8)Dione Derivative in Polar Solvents

Abstract

Using stationary luminescence and pulse fluorometry methods, spectral-kinetic and photophysical properties of 9 methyl-10-hydroxi acridine(1,8)dione derivative dye (9,10-ACD) in polar (protonic and nonprotonic) solvents at 293 and 77 K have been investigated. For the first time, a new long-wavelength fluorescence band (LF, 670–710 nm) in polar protonic (methanol, ethanol) and nonprotonic (N,N-dimethylformamide, dimethylsulfoxide) at room temperature was revealed. This band has been formed from the high lying (in the range of 460–490 nm) singlet excited state responsible for the short-wavelength fluorescence band (SF). The LF is not revealed in low polar (methylene chloride), polar nonprotonic (acetonitrile) and high viscose protonic (glycerol) solvents at 293 K, as well as at 77 K in ethanol. It arises as a result of deprotonation of a molecule in an excited state and emission of the resulting anion in the long-wavelength region. Based on the analysis of the spectral and kinetic data of the SF decay and the LF rise, a mechanism for the dye anion formation depending on the basicity of the polar solvent is proposed. Possible practical applications of the revealed spectral effect in biology, medicine and analytical chemistry are proposed.