N,N-Difluoro O-trifluoromethyl-hydroxylamine , CF3ONF2: conformation and vibrational analysis studied by experimental and theoretical methods

ERBEN, M. F.; DELLA VÉDOVA, C. O.; WILLNER, H.

JOURNAL OF MOLECULAR STRUCTURE

Elsevier B.V.

Año: 2004 vol. 692 p. 63 - 70

0022-2860

Infrared spectra in the gas phase and in argon matrix and Raman spectra in the liquid phase were recorded for N,N-difluoro-Otrifluoromethyl-hydroxylamine, CF3ONF2. The presence of one single conformer could be demonstrated by heating the Ar/CF3ONF2 mixture at different temperatures between 20 and 245 ºC with subsequent quenching of the mixture at 15 K as a matrix due to the absence of any change in the relative band intensities the IR matrix spectra. From quantum chemical calculations (B3LYP and B3PW91/6-311 þ G(3df) and MP2/6-311 þ G*), the syn conformation (syn orientation of the nitrogen lone pair with respect to the C–O bond, d(CON:)= 0º) is preferred. A second gauche inner form ( d(CON:)= 165º)) is calculated to be higher in energy by about 5 kcal/mol. The syn conformational preference is discussed in terms of the natural bond orbital population analysis.