On the structure and spectra of dinitramide salts

The preparation for the isotopically substituted dinitramide salts has been proposed. The N-14 and N-15 NMR spectra of the N-15-enriched dinitramide anion in solution are measured and interpreted for the first time. New experimental IR and Raman spectra are obtained for the NH4+ and K+ salts of dinitramide in the solid state and in solution. The assignments are made with the help of quantum-mechanical force field calculations and normal-coordinate analysis. The harmonic vibrational spectrum of the dinitramide anion calculated at the B3LYP/6-31 + G(d) level in the presence of solvent correlates best with the experimental data. The structure and spectra of the M+CH(NO2)(2)(-) and M+N(NO2)(2)(-) (M denotes a counterion) are compared and discussed. Topology of the electron charge density in the dinitramide anion is analyzed within the framework of Bader's theory of atoms in molecules. (C) 2001 Elsevier Science B.V. All rights reserved.