The next compound targeted was 2,4,6-trintrophenyl azide which is an analogue of TNT
(trinitrotoluene) a commercial explosive thus making the target compound a possible HEDM.
2,4,6-trintrophenyl azide (picryl azide) was prepared by nitration of the previously prepared
o-nitrophenyl azide with fuming nitric acid.
The 2,4,6-trintrophenyl azide was isolated as a yellow powder and was recrystallised from
methanol to yield yellow needles with a melting point of 89-90°C, dec. The elemental
analysis for 2,4,6-trintrophenyl azide was in agreement with the theoretical values, (found C,
27.8 ; H, 0.8 ; N, 32.6 % calculated C, 28.4 ; H, 0.8 ; N, 33.1 %).The IR spectrum showed a
strong absorption at 2137 cm-1 for the asymmetric stretching vibration of the azide group, a
strong absorption at 1288 cm-1 for the symmetric stretching vibration of the azide and an
absorption at 623 cm-1 for the deformation of the azide group. The IR spectrum also showed
two weak absorptions at 3108 and 3096 cm-1 which are characteristic for C-H vibrations in an
aromatic ring, a strong absorption at 1603 cm-1 for the asymmetric stretching vibration of the
C-C bond in the aromatic ring, a strong absorption at 1536 cm-1 for the asymmetric stretching
vibration of the NO2 group and a strong absorption at 1351 cm-1 for the symmetric stretching
vibration of the NO2 group. The Raman spectra showed a peak at 2127 cm-1 for the
asymmetric stretching vibration of the azide group, a strong peak at 1287 cm-1 for the
symmetric stretching vibration of the azide. The Raman spectrum also showed a peak at 1556
cm-1 for the asymmetric stretching vibration of the C-C bond in the aromatic ring, a peak at
1537 cm-1 for the asymmetric stretching vibration of the NO2 group and a strong peak at 1350
cm-1 for the symmetric stretching vibration of the NO2 group. The ab initio calculation of the
vibrational frequencies for 2,4,6-trintrophenyl azide was carried out at the self consistent HF
level of theory using a 6-31G(d) basis set with a scaling factor of 0.89 [26].
|