REACTIONS OF THE HEXACHLOROCYCLODIPHOSPHAZANE [MENPCL3]2 WITH PRIMARYAROMATIC-AMINES - FORMATION OF HIGHLY BASIC BISPHOSPHINIMINES

Reactions of hexachlorocyclodiphosphazane [MeNPCl3]2 with primary arom atic amines afforded the bisphosphinimine hydrochlorides [(RNH)2(RN)PN (Me)P(NHMe)(NHR)2]+Cl- (R = Ph 1, C6H4Me-4 2 or C6H4OMe-4 3). Dehydroc hlorination of 2 and 3 by methanolic KOH yielded highly basic bisphosp hinimines [(RNH)2(RN)PN(Me)P(NMe)(NHR)2] (R = C6H4Me-4 4 or C6H4OMe-4 5). Compounds 1-5 have been characterised by elemental analysis and IR and NMR (H-1, C-13, P-31) spectroscopy. The structure of 2 has been c onfirmed by single-crystal X-ray diffraction. The short P-N bond lengt hs and the conformations of the PN, units can be explained on the basi s of cumulative negative hyperconjugative interactions between nitroge n lone pairs and adjacent P-N sigma orbitals. Ab initio calculations on the model phosphinimine (H2N)3P=NH and its protonated form suggest that (amino)phosphinimines would be stronger bases compared to many or ganic bases such as guanidine.