Tautomers and conformers of malonamide, NH2-C(O)-CH2-C(O)-NH2: vibrationalanalysis, NMR spectra and ab initio calculations

The conformational and tautomeric compositions of malonamide, NH2-C(O)-CH2- C(O)-NH2 were determined by vibrational spectroscopy and theoretical calcul ations (HF/6-31G*, B3PW91/6-31G*). Solid state Fourier transform infrared a nd Raman spectra were analysed. They reveal the existence of a diketo tauto mer. Theoretical calculations predict a diketo structure belonging to the C -1 symmetry group. No enol form is present in the molecule in the solid. C- 13-NMR studies show only signals of a diketo tautomer. (C) 2000 Elsevier Sc ience B.V. All rights reserved.