Crystal and molecular structure of 2,2,4,6,6-pentamethyl-5-benzoyl-4-(N-methylbenzamido)-1,3-diaza-2,4,6(Pv)-triphosphorin

Crystals of 2,2,4,6,6-pentamethyl-5-benzoyl-4-(N-methylbenzamido)-1,3-diaza-2,4,6(P v )-tri-phosphorin are triclinic, a = 13.375(1), b = 11.313(1), c = 7.925(1) Å, α = 107.72(1), β = 98.23(1), γ = 87.00(1)°, Z = 2, space group [Formula: see text]. The structure was solved by Patterson and Fourier syntheses and was refined by full-matrix least-squares procedures to a final R of 0.067 and R w of 0.089 for 3954 reflections with. I ≥ 3σ(I) The P 3 N 2 C ring is nearly planar and has a conformation corresponding to a flattened version of the chair – twist boat. Bond lengths in the azaphosphorin ring, P—N, 1.579–1.614(2), and P—C, 1.752(3) and 1.777(3) Å, indicate conjugation with the C-benzoyl group. The exocyclic P—N bond length, 1.742(3) Å, is longer than those in related compounds as a result of competitive electron withdrawal from the N-benzoyl group. Other bond lengths (corrected for libration) are: mean P—Me, 1.796(4); C=O, 1.242(3) and 1.247(4); C—N, 1.472(3) and 1.369(4); mean C—C(phenyl), 1.391(10); other C(sp 2 )—C(sp 2 ); 1.417–1.518(4) Å.