The stereochemistry of the phosphorus-selenium bond. VII. Structure of 5,5-dimethyl-2-(o-nitrophenyl)amino-1,3,2-dioxaphosphorinane 2-selenide.

C11H15N2O4PSe, Mr = 349.2, monoclinic, P2(1)/c, a = 10.204(3), b = 19.891 (3), c = 6.823 (3) A, beta = 94.41 (3) degrees, U = 1380.8 A3, Z = 4, Dm = 1.66, Dx = 1.68 Mg m-3, Mo K alpha, lambda = 0.71069 A, mu = 3.05 mm-1, F(000) = 704, room temperature, R = 0.026 for 1755 observed reflections [I greater than 3 sigma (I)]. The dioxaphosphorinane ring adopts a flattened chair conformation with P = Se and P-N bonds in equatorial and axial positions respectively. The properties of the molecule are mainly governed by anomeric interactions between endocyclic oxygen lone pairs and antibonding orbitals of the axial P-N bond.