The Crystal Structure of a Spirocyclic Cyclophosphazene N3P3(NM e2)4(NHCH2CH2NH) - Evidence for Intermolecular Hydrogen Bonding

Becke-Göhring and Boppel [1] studied the reaction of hexachlorocyclotriphosphazene, N3P3CI6 with ethylenediamine and isolated the tetrachloro(ethylenediamino) derivative, NaPsCMNHCHaCHaNH) to which an ansa type structure (chlorine atoms replaced from two phosphorus atoms) was assigned [2, 3]. A reinvestigation of the reaction has been reported recently [4] and a spirocyclic structure (1) (chlorine atoms replaced from the same phosphorus atom) has been assigned on the basis of 1 H and 31P NMR data for its dimethylamino derivative, N3P3(NMe2)4(NHCH2CH2NH) (2). In order to confirm the structural assignment, an X-ray crystallographic study of compound (2) has been carried out, the results of which are reported in this paper. Compound 2 represents the first example of a cyclotriphosphazene derivative containing mixed amino substituents to be studied by X-ray crystallography.