Les liaisons phosphore-azote via l'étude cristalline et moléculaire d'un iminodiazaphospholane

Iminodiazophospholane 1 was obtained as monoclinic crystals, space group P2 1 /c with a = 10.243(9), b = 17.236(5), c = 11.992(9) Å, and Z = 4. The structure was determined by single-crystal X-ray diffraction and was refined up to R = 0.056[Formula: see text]for 1342 reflections. The geometry of the molecule is that of a distorted tetrahedron with [Formula: see text] angles varying from 91.8° (ring angle) to 121.7° for [Formula: see text]. The diazophospholane ring has an envelope conformation where one of the 2 carbon atoms is at the tip. The three tricoordinated nitrogen atoms have a planar structure; the lone pairs on the two ring nitrogens have parallel orientation and both are orthogonal to the lone pair of the exocyclic nitrogen atom (N 7 ). The P—N bond lengths are relatively short, falling between 1.620 Å and 1.669 Å, while the P 2 =N 6 bond of 1.539 Å is among the smallest values ever reported. The multiplicities of the P—N bonds were assigned on the basis of an empirical method: 0.10 for the two cyclic P—N, 0.25 for the exocyclic P—N, and 0.60 for [Formula: see text] [Journal translation]