Photochemistry and photophysics of osazones. Part 3.—Properties of D-arabino-hexulose phenylosazone in excited singlet and triplet states

Abstract

Steady-state measurements of the sensitization and quenching of N—PH → O—PH photoisomerization and the fluorescence of the N—PH isomer, together with dynamic measurements of the decay of fluorescence and of T₁→ T_n absorption, have been performed to determine the singlet and triplet energy levels of the planar and twisted configurations for D-arabino-hexulose phenylosazone (PH). The emission and excitation spectra have been measured and the fluorescence quantum yields have been obtained at 293 and 77 K. With a nanosecond laser photolysis system triplet–triplet absorption spectra have been measured and the molar absorption coefficient of the T₁→ T_n transition has been determined for N—PH.