Studies of phosphazenes. Part 30. Reactions of hexachlorocyclotriphosphazene with aromatic primary amines: interplay of geminal and non-geminal modes of chlorine replacement

The reactions of hexachlorocyclotriphosphazene, N3P3Cl6, with aromatic primary amines (aniline, p-toluidine, and p-anisidine) yield the derivatives N3P3Cl6–n(NHC6H4Y-p)n[Y = H, Me or OMe, n= 1 or 2 (three isomers); Y = OMe, n= 3 (three isomers), 4 (geminal isomer only), 5, or 6]. The structures of these derivatives and their isomeric compositions have been determined by 31P n.m.r. spectroscopy and also by 1H n.m.r. spectra of the corresponding methoxy and/or dimethylamino derivatives. When diethyl ether, tetrahydrofuran, or MeCN is used as the solvent, non-geminal products predominate at the bis stage of chlorine replacement. However, in the presence of triethylamine, the geminal product is formed exclusively. At the tetrakis stage of chlorine replacement, the geminal isomer is the sole product irrespective of the reaction medium. The reaction of non-gem-N3P3CL3[NHC6H4(OMe)-p]3 with p-anisidine yields only N3P3[NHC6H4(OMe)-p]6; formation of non-geminal tetrakis derivatives could not be detected. The mechanistic implications of these results are discussed.