Infrared Spectra of Biuret-hydrate and Its Deuterated Compound

Abstract The infrared spectra between 4000 and 33 cm−1 of biuret-hydrate and between 4000 and 250 cm−1 of its deuterated compound have been recorded. The vibrational assignments have been made by referring to the infrared spectra of the related compounds and the isotopic frequency shift. Normal coordinate analysis of the in-plane vibrations of biuret and biuret-d5 as twelve-body problem has been carried out by using the molecular model of the planar trans-cis conformation. A simple Urey-Bradley force field has been employed and the force constants have been refined by the least squares method. The calculation of potential energy distributions has shown that the NH in-plane deformation and the CN stretching vibrations couple appreciably with each other and give the imide II and III bands at 1515 and 1365 cm−1, respectively, just as in the case of diacetamide.