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The Phosphorescence Bands of Anthraquinone in Crystalline Solvents at 77°K

1970; Oxford University Press; Volume: 43; Issue: 11 Linguagem: Inglês

10.1246/bcsj.43.3373

1348-0634

Akira Kuboyama,

Lanthanide and Transition Metal Complexes

Abstract The phosphorescence bands of anthraquinone in the solvents used in this work are all safely assigned to the π*→n bands on the basis of their short lifetimes. In n-paraffins (n-hexane, n-heptane, and n-octane), two phosphorescence bands which are close to each other are found. Considering the dependence of the relative intensities of these two phosphorescence bands on the carbon-numbers of the n-paraffins, it is assumed that the longer- and the shorter-wavelength bands are due to the anthraquinone molecules with the C–O bond axis parallel to and perpendicular to the longitudinal axis of the planar zig-zag form of the n-paraffin molecules in the n-paraffin crystals respectively. In chloroform and dioxane, a broad phosphorescence band shows a blue-shift relative to the corresponding band in the alkane solvents. In chloroform a sharp phosphorescence band was also observed for a solution which was rapidly cooled. This sharp band is assumed to be due to the anthraquinone molecules with a certain geometry relative to the surrounding chloroform molecules.