Crystal structure of 2-azido-1,3-bis-(2,6-diiso-propyl-phen-yl)-1,3,2-di-aza-phospho-lidine

The title compound, C₂₆H₃₈N₅P, was synthesized by reacting 2-chloro-1,3-bis-(2,6-diiso-propyl-phen-yl)-1,3,2-di-aza-phospho-lidine with sodium azide and a catalytic amount of lithium chloride in tetra-hydro-furan. The title compound is the first structurally characterized 2-azido-1,3,2-di-aza-phospho-lidine and exhibits a P atom in a trigonal pyramidal geometry. The azide P-N bond length of 1.8547 (16) Å is significantly longer than the P-N separations for the chelating di-amine [P-N = 1.6680 (15) and 1.6684 (14) Å]. The sterically hindered 2,6-diiso-propyl-phenyl groups twist away from the central heterocycle, with dihedral angles between the central heteocyclic ring and benzene rings of 76.17 (10) and 79.74 (9)°. In the crystal, a weak C-H⋯N link to the terminal N atom of the azide group leads to [100] chains.