Analyses structurales et spectrales du 5,6-diméthyluracile

The molecular structure of 5,6-dimethyluracil monohydrate C6H8N2O2H2O has been determined by X-ray diffraction method. The crystals are monoclinic space group P21/n with a = 6.667 (2), b = 6.784 (4), c = 16.759 (2) A, β = 99.08 (2)° , V = 748.6 (5) A3 and z = 4. The structure was refined to R = 0.064. The Raman and infrared spectra of the crystalline powders of the 5,6-dimethyluracil monohydrate, anhydrous and deuterated forms were investigated from 4000–200 cm−1. An assignment of the normal modes is proposed. RESUME La structure moleculaire du 5,6-dimethyluracile monohydrate C6H8N2O2H2O a ete determinee par diffraction des rayons X. Les cristaux appartiennent au groupe d'espace monoclinique P21/n avec a = 6,667 (2), b = 6,784 (4), c = 16,759 (2) A, β = 99, 08 (2), V = 748,6 (5) A3 et z = 4. La structure a ete affinee jusqu'a un facteur R = 0,064. Les spectres Raman et infrarouge des poudres cristallines du 5,6-dimethyluracile monohydrate, anhydre et deuterie ont ete analyses de 4000 a 200 cm−1. Une attribution de l'ensemble des vibrations fondamentales a ete proposee. Copyright © 2008 John Wiley & Sons, Ltd.