Studies in cyclophosphazenes. Part 11. Geminal amination of (alkylamino)pentachlorocyclotriphosphazenes via a conjugate-base mechanism

Abstract

Geminal amination of aminocyclotriphosphazenes is believed to proceed via a conjugate-base mechanism, but no study of this mechanism has been reported. Therefore in an endeavour to test this the effect of base concentration on the ratio of geminal to non-geminal products in the general reaction N₃P₃Cl₅(NRR′)+ NHR″R‴ [graphic omitted] N₃P₃Cl₄(NRR′)(NR″R‴)+ base·HCl (R,R′,R″,R‴= H or alkyl) has been investigated. The influence of the substituent groups, the amine, the solvent, and the base and its concentration have been studied. Geminal isomer formation was found to be enhanced by increased base concentration, but only if the phosphazene had a primary amine substituent. These findings conform with the proposed proton abstraction mechanism but conflict with another postulated mechanism.