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

The title compound, C26H38ClN2OP, was synthesized by reacting phosphoryl chloride with N,N'-bis-(2,6-diiso-propyl-phen-yl)ethane-1,2-di-amine in the presence of N-methyl-morpholine which acted as an auxilliary base to quench the HCl released as a by-product. The resultant N-heterocyclic phosphine five-membered ring adopts a half-chair conformation and features a tetra-coordinate P atom ligated by the chelating di-amine [P-N = 1.6348 (14) and 1.6192 (14) Å], one double-bonded O atom [P1-O1 = 1.4652 (12) Å] and one Cl atom [P1-Cl1 = 2.0592 (7) Å]. The sterically hindered 2,6-diiso-propyl-phenyl (Dipp) groups twist away from the central heterocycle, with torsion angles of -75.66 (19) and 83.39 (19)° for the P-N-Car-Car links. A number of intra-molecular C-H⋯N, C-H⋯O and C-H⋯Cl close contacts occur. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds to generate [010] chains. C-H⋯π inter-actions are also observed.