Phosphorus–nitrogen compounds. Part XX. The reaction of piperidine with hexachlorocyclotriphosphazatriene; the replacement pattern and the structure of the products; the “cis-effect”

Abstract

The reaction of hexachlorocyclotriphosphazatriene with piperidine leads to a series of derivatives, N₃P₃Cl_6–n(NC₅H₁₀)_n(n= 1, 2, 3, 4, or 6). Pairs of isomers were obtained for the di-(cis and trans) and tri-(trans and geminal) derivatives; a third tri-isomer (cis) was obtained by an isomerisation reaction. The preparation of mixed dimethylamino-piperidino-derivatives, N₃P₃(NMe₂)_6–n(NC₅H₁₀)_n, by reaction of chlorodimethylaminocyclotriphosphazatrienes, N₃P₃Cl_6–n(NMe₂)_n, and of the above chloro-piperidino-derivatives with piperidine and dimethylamine, respectively, leads to structural assignments for the chloro-piperidino-derivatives. These assignments indicate that the replacement by piperidino residues in hexachlorocyclotriphosphazatriene proceeds mainly by a non-geminal reaction scheme. A “cis-effect” is postulated to account for the observed reaction pattern of dimethylamine and piperidine with hexachlorocyclotriphosphazatriene. The ¹H n.m.r. spectra of all the above derivatives are reported and discussed.