Spectroscopic and theoretical studies of N-trichlorophosphazotrifluoroacetyl, CF3C(O)NPCl3 and N-trichlorophosphazotrichloroacetyl, CCl3C(O)NPCl3

FTIR, Raman and NMR spectra of N-trichlorophosphazotrifluoroacetyl, CF3C(O)NPCl3 (1) and N-trichlorophosphazotrichloroacetyl, CCl3C(O)NPCl3 (2) were obtained. The experimental data are compared with results of ab initio and density functional theory (DFT) calculations. According the theoretical studies the main conformer for both molecules possesses Cs symmetry (CO bond syn respect to the NP bond). The preference of the syn conformation has been rationalized based on the natural bond orbital formalism. The vibrational spectra of 1 in the liquid phase and 2 in the solid phase are in good agreement with theoretical results.