Azomethine derivatives. Part IX. Preparation of dialkylideneammonium salts via diarylketiminodiphenylmethyl chlorides

Abstract

The diarylketiminodiphenylmethyl chlorides Ph₂C:NCClPh₂ and p-tolyl₂C:NCClPh₂ have been prepared from Ph₂CCl₂ and R₂C:NLi in benzene. Reactions, normally in toluene, between these chlorides and the Lewis acids BCl₃, AlCl₃, and SbCl₅ have been used to prepare the dialkylideneammonium salts Ph₂C:N:CPh₂⁺ MX_n^–(MX_n^–= BCl₄^–, AlCl₄^–, or SbCl₆^–) and p-tolyl₂C:N:CPh₂⁺ SbCl₆^–, the ionic structures of which are supported by their electrical conductivities in nitrobenzene, and also by a band in their i.r. spectra centred at 1845 cm.^–1, assigned to ν(C:N:C). The ion Ph₂C:N:CPh₂⁺ also features prominently in the mass spectrum of Ph₂C:NCClPh₂.

Unsuccessful attempts to prepare the tetraphenylborate Ph₂C:N:CPh₂⁺ BPh₄^– from Ph₂C:NCClPh₂+ NaBPh₄, and from Ph₂C:NH₂⁺Cl^–+ NaBPh₄+ Ph₂C:Y (Y = O or NH) are described. Ph₂C:NH₂⁺ Cl^– and NaBPh₄ in boiling toluene gave Ph₂C:NBPh₂. Ph₂CCl₂ and 2Ph₂C:NLi in boiling toluene gave (Ph₂C:N)₂CPh₂.