Crystal structure of compounds with (N–P)n rings. Part XI. 1,2,3,4-Tetraphenyl-2,4-dithiocyclodiphosphazane, [PhNP(S)Ph]2

Abstract

The crystal structure of the title compound (I; R = Ph) has been determined from 5873 three-dimensional X-ray intensity data collected on a diffractometer. The structure was solved by the symbolic addition method and refined by block-diagonal least-squares to R 7·5%.

The triclinic unit-cell, space group P[(a= 9·510(2), b= 14·195(2), c= 9·866(2)Å, α= 85·43(1), β= 94·30(1), γ= 59·77(1)°] contains two molecules, which lie on inversion centres at ½,½,½ and ½,0,0. Owing to the inversion symmetry the molecules have a planar (N–P)₂ ring and the substituents at the phosphorus atoms are trans. The P–N bonds are equal and the bonding arrangement around the nitrogen atoms is planar. Around the phosphorus atoms the arrangement is distorted tetrahedral. The approximate molecular symmetry is C_2h. Mean values (and individual standard deviations) of bond lengths and valence angles are: P–N 1·695(4), P–S 1·913(2), P–C 1·796(6), N–C 1·418(6), and C–C 1·386(8)Å; P–N–P 98·1(4), P–N–C 130·9(4), N–P–N 81·9(2), S–P–C 114·8(2), and C–C–C 120·0(6)°.