Studies in cyclophosphazenes. Part 6. Configurations of the non-geminal tetrachlorobis(dialkylamino)cyclotri(λ5-phosphazenes)

Abstract

A method for determining the cis and trans configurations of 2,4,6,6-tetrachloro-2,4-bis(dialkylamino) cyclotriphosphazenes has been developed, and its validity established for compounds of known configuration. The method employs the ¹⁹F n.m.r. spectra of the cis- and trans-2,4-dichloro-2,4-bis(dialkylamino)-6,6-difluorocyclo-triphosphazenes, which are prepared, with retention, from the corresponding isomers of the title compounds. These spectra enable unequivocal identification of the isomeric configurations of the precursors. By application of the method to the known pairs of compounds in the above class, the configurations previously assigned to the diethylamino- and piperidino-compounds have been confirmed. Prior conflicting assignments made for the morpholino- and pyrrolidin-1-yl isomers have been resolved. Some implications of these results are discussed.