5-Cyclo-hexyl-1,3-diphenyl-1,3,5-di-aza-phosphinane, its phosphine oxide, and its [NiCl₂ L ₂] complex

The crystal structures of 5-cyclo-hexyl-1,3-diphenyl-1,3,5-di-aza-phosphinane, C₂₁H₂₇N₂P, and its oxidized phosphine oxide, 5-cyclo-hexyl-1,3-diphenyl-1,3,5-di-aza-phosphinan-5-one, C₂₁H₂₇N₂OP, have primitive monoclinic symmetry (both in space group P2₁/m) at 150 K. The nickel(II) complex trans-di-chlorido-bis-(5-cyclo-hexyl-1,3-diphenyl-1,3,5-di-aza-phosphinane-κP)nickel(II), [NiCl₂(C₂₁H₂₇N₂P)₂], consists of two di-aza-phosphinane ligands (monoclinic C2/c, 150 K) bound through their phospho-rous atoms, which adopts a four-coordinate square-planar geometry. The bulky cyclo-hexyl substituents of the ligand are axially positioned in their respective chair six-membered ligand rings, and are in an anti-configuration, with respect to the square plane. The nickel atom is located on a center of symmetry.