High-resolution 13C nuclear magnetic resonance spectra of some solid anthraquinone dyestuffs and related species

Abstract

¹³ C N.m.r. spectra of the solid phase have been obtained for anthraquinone and a series of its substituted derivatives. Whilst some species show essentially similar spectra in the solid and solution phases, clear differences are apparent in other cases. The differences are attributed to the loss of molecular symmetry associated with the locking of particular conformations in the solid. In the case of 1,4-bis-(n-butylamino)-anthraquinone, the molecular asymmetry indicated by n.m.r. in the solid was confirmed subsequently by X-ray crystallographic examination.