Acidic and basic properties of nitramide, and the catalysed decomposition of nitramide and related compounds: an ab initio theoretical investigation

Deprotonation from nitrogen of the aci-nitro tautomer (4) of nitramide (1) has been shown to give an anion which does not correspond to an energy mini mum on the potential energy surface. The base-catalysed decomposition of ni tramide via this tautomer. therefore, occurs by an enforced concerted mecha nism which, on the basis of previously reported experimental results. is de duced to be highly asynchronous. Protonation of 4 on the hydroxy also leads to an ion which spontaneously fragments, consequently the acid-catalysed d ecomposition of I via 4 also involves concerted proton transfer and fragmen tation. The uncatalysed decomposition of nitramide through the same tautome r 4 is also concerted, and the mechanism through a cyclic transition struct ure involving two water molecules is shown to be more favourable than a cyc lic concerted mechanism involving a single water molecule. Structures and e nergies of all relevant species have been calculated and shown to be in goo d agreement with experimental results where these are available.