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

The reactions of hexachlorocyclotriphosphazene, $N_3P_3CI_6$, with aromatic primary amines (aniline, \rho-toluidine, and \rho-anisidine) yield the derivatives $N_3P_3CI_{6-n}{( NHC_6H_4Y-\rho)}_n$, [Y = H, Me, or OMe, n = 1 or 2 (three isomers); Y = OMe, n = 3 (three isomers), 4 (geminal isomer only), 5, or 61. The structures of these derivatives and their isomeric compositions have been determined by ,$^{31}P$ 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. A t the tetrakis stage of chlorine replacement, the geminal isomer is the sole product irrespective of the reaction medium. The reaction of non-gem-$N_3P_3CI_6,{[NHC_6H_4(OMe)-\rho]}_3$, with \rho-anisidine yields only $N_3P_3{[NHC_6H_4(OMe)-\rho]}_6$; formation of non-geminal tetrakis derivatives could not be detected. The mechanistic implications of these results are discussed