STRUCTURES OF 3 DIARYL-SUBSTITUTED TRIPHENYLPHOSPHAZINES

9-Fluorenone triphenylphosphazine (1), C31H23N2P, M(r) = 454.51, orthorhombic, Pbca, a = 22.312 (11), b = 11.510(10), c = 18.744 (9) angstrom, V = 4813 (5) angstrom3, Z = 8, D(x) = 1.25 g cm-3, lamda(Mo Kalpha) = 0.71069 angstrom, mu = 1.31 cm-1, F(000) = 1904, T = 294 K, R = 0.047 for 2531 observed reflections. 10,11-Dihydro-5H-dibenzo[a,d]cyclohepten-5-one triphenylphosphazine (II), C23H27N2P, M(r) = 482.57, orthorhombic, P2(1)2(1)2(1), a = 22.645 (5), b = 9.190 (10), c = 12.568 (2) angstrom, V = 2615 (3) angstrom3, Z = 4, D(x) = 1.23 g cm-3, lambda(Mo Kalpha) = 0.71069 angstrom, mu = 1.24 cm-1, F(000) = 1016, T = 294 K, R = 0.054 for 2710 observed reflections. Benzophenone triphenylphosphazine (III), C31H25N2P, M(r) = 456.53, monoclinic, P2(1)/c, a = 13.730 (5), b = 17.205 (10), c = 10.914 (4) angstrom, beta = 109.36 (1)-degrees, V = 2432 (1) angstrom3, Z = 4, D(x) = 1.25 g cm-3, lambda(Mo Kalpha) = 0.71069 angstrom, mu = 1.30 cm-1, F(000) = 960, T = 294 K, R = 0.058 for 2541 observed reflections. The results confirm that the C-N-N-P phosphazine link is planar, implying strong conjugation, and that in (III) one of the C-phenyl substituents lies in a plane orthogonal to the C-N-N-P plane; both these findings accord with predictions made on the basis of kinetic studies of phosphazine formation.