Crystal structure of 4,4,6,6-tetrachloro-2,2-di-t-butylaminocyclotriphosphazene

Abstract

Crystals of the title compound are orthorhombic, with a= 20.41(1), b= 11.96(1), and c= 15.97(1)Å, space group Pna2₁, and Z= 8. The atomic positions have been determined by direct methods from X-ray diffractometer data and refined by full-matrix least squares to R 0.062 for 2 139 observed reflections. The two t-butylamino-groups are attached to the same phosphorus atom and the compound is thus the geminal isomer. The asymmetric unit consists of two independent molecules with similar molecular parameters which are linked together by two hydrogen bonds. The P₃N₃ rings both have a slight boat conformation with P–N(ring) bonds of 1.61 Å for the amine-substituted phosphorus atoms and 1.56 Å for those carrying chlorine substituents. Bond angles in the ring also vary. Mean values for other parameters are P–N(amine) 1.609, P–Cl 2.001 Å, N–P–N(exo) 104.0 and Cl–P–Cl 99.3°.