DO I 4HN1 : 1 and 2 : 1 products formed by nucleophilic attack of ammonia in liquid ammonia solutions of 1,3,5trinitrobenzene and of 2,4,6-trinitrotoluene have been observed by 13C n.m.r. spectroscopy. In the latter reaction three 2: 1 products are observed: two geometrical isomers formed by attack at the 1and 3position of 2,4,6-trinitrotoluene and a structural isomer formed by attack at the 3and 5-position.Ammonia behaves as a nucleophile towards a-electron-deficient molecules such as 1,3,5-trinitrobenzene (TNB) and 2,4,6trinitrotoluene (TNT) especially when these molecules are dissolved in the effective ionising solvent liquid ammonia. There is extensive evidence that, at least in the case of TNB, the initial step is the formation of the zwitterion (1) followed by deprotonation by a second molecule of ammonia to form the anionic species (2) (Scheme). The product is a typical Jackson '-Meisenheimer (o-anionic) compound." An earlier ' H n.m.r. study ' of the TNB-liquid ammonia system had shown that, at 220 K, the initial formation of (2) was rapidly followed by almost complete conversion into (3). Only one of the two possible geometrical isomers represented by (3) was observed. From the 'H n.m.r. absorption spectra, it was apparent that the formation of (3) from (2) was reversible, although at 240 K the equilibrium was still in favour of (3). No free TNB was observed.A corresponding 'H n.m.r. study l o of the products formed by dissolving TNT in liquid ammonia produced rather similar results. However, the general Scheme, with the formation of (4) and (S), both geometrical isomers of (6), was observed. In those experiments the structural isomer (7) was not detected.We have now restudied both systems using 13C n.m.r. spectroscopy.

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