The vibrational spectra and structures of nitramide and its methyl derivatives

Abstract

The infra-red spectra of nitramide and its mono-and dimethyl-derivatives have been studied between 2 and 25 p : deuteration of the nitramide was also effected. The results show the amino structure NH2 . NO2 as the only one observable for the molecule. Hydrogen bonding is very weak in crystalline nitramide. Some evidence that the molecule approximates to, if it does not attain, an all-planar configuration and clear evidence of bonding above that of a mingle bond in the (N-N) link is adduced. Some assessments of the bonding within the (NH2) and (NOz) groups are presented.As originally suggested by Thiele and Lachmann 1 nitramide is usually written H2N . NO2 although Hantzsch 2 over a number of years advanced alternatives, most significantly the aci-form HN : NO . OH. Some kinetic and optical evidence was adduced in favour of this 3 although later kinetic study4 was interpreted as supporting the amino-structure. The dipole moment 5 was taken to indicate a further alternative, N = N(OH)2, but the Raman spectrum described by Kohlrausch and Wittek 6 suggested the usually accepted structure. Whilst the present studies were in progress Beevers and Trotman-Dickinson 7 reported an X-ray crystallographic investigation which, although not locating the hydrogen atoms precisely, is consistent with the amino form.

The infra-red spectrum and structure of cyanamide and dimethylcyanamide

“…These figures correspond to a shift of at least lS0 cm-1 in N-methyl acetamide for the same phase changes and indicates appreciable H-bonding in the cyanamide liquid which increases insignificantly on passing to I800 1700 l6OOlSOO 1 4 0 0 1 3 0 0 1200 1 1 0 0 1000900 800 700 6 View Article Online 3000-800 cm-1 Above 8OOcm-1 the only other significant absorptions are at 2762, 2260, 1642, 1582 and 1125 cm-1. I n passing from solution to the liquid and solid states the mean v (NH) value decreases first by 104 cm-1 and then by a further 17 cm-1.…”

Studies on nitramide and its methyl derivatives with ab initio calculations. IV. The harmonic force field and vibrational spectra of dimethylnitramine and its isotopic derivatives

“…stretch (4) N-C antisym. stretch (5) CLH stretch 6 -1 1 ) C -H bend (12)(13)(14)(15)(16)(17)(18)(19)(20)(21) C-N-N sym. deformation (22) experimental data in vapor state have been optimized (as given in Table 5, TI) to give a more accurate force field of dimethylnitramine (as seen in Table 3).…”

“…Experimental Vibrational spectra study of dimethylnitramine dates back to the early study by Kohlrausch and Witteck in 1948.l' The more complete IR spectra involving gas phase data were derived by Davies et al in 1958. 18 Trinquecoste et alle reported in 1974 the IR and Raman spectra in solid phase of both DMNA and its deutero-derivative(-6D) together with complete assignments which were based on the calculation using "force constants transfer" method. For theoretical studies, we would be interested in the experimental spectrum in gas phase because the computation is rigorously suitable for free molecules.…”

Light induced transformations of small nitroso compounds in low temperature rare gas matrices

“…Following the above reaction sequence one would intuitively expect this reaction to be part of the decomposition of nitramide (H2NNO2) , which is known to yield N20 and H20 [90][91][92][93][94][95][96][97].…”