STUDIES OF THE REACTION BEHAVIOR OF NITRYL COMPOUNDS TOWARDS AZIDES -EVIDENCE FOR TETRANITROGEN DIOXIDE, N4O2

The reaction behavior of NaN3, AgN3, and Me3SiN3 towards FNO2, CINO2, NO2SbF6, and NO2BF4 was investigated. At -30-degrees-C or below in a s olvent-free system sodium azide did not react with CINO2, NO2BF4, or N O2SbF. Below -30-degrees-C silver azide did not react either with neat CINO2. Treatment of Me3SiN3 with pure CINO2 led to the formation of C lN3, N2O, and Me3SiOSiMe3. A mechanism for this reaction has been prop osed. Pure chlorine azide was isolated by fractional condensation and identified by its low-temperature Raman spectrum (liquid state). The r eaction of Cp2Ti(N3)2 with ClNO2 also yielded ClN3 as the only azide-c ontaining reaction product. Treatment of FNO2 with NaN3 at temperature s as low as -78-degrees-C always ended in an explosion which was proba bly due to the formation of FN3 as one of the reaction products. The r eaction of NO2SbF6 with NaN3 in liquid CO2 (-55-degrees-C less-than-or -equal-to T less-than-or-equal-to -35-degrees-C) as the solvent afford ed a new azide species which was stable at low temperature in solution only and was investigated by means of low-temperature Raman spectrosc opy. The obtained vibrational data give strong evidence for the presen ce of tetranitrogen dioxide, N4O2, which can be regarded as nitryl azi de (NO2N3). The structure and vibrational frequencies of N4O2 were com puted ab initio at correlated level (MP2/6-31 + G). In liquid xenon ( -100-degrees-C less-than-or-equal-to T less-than-or-equal-to -60-degre es-C) NaN3 did not react with NO2SbF6. A previous literature report on the preparation of N4O2 could not be established.