STRUCTURE OF 5-PHENYLDIBENZOPHOSPHOLE

C18H13P, M(r) = 260.3, orthorhombic, Pbc2(1) [alternative setting of Pca2(1) 0.29)], a = 8.486 (2), b = 12.387 (3), c = 26.244 (5) angstrom V = 2759 (1) angstrom3, Z = 8, D(x) = 1.25 g cm-3, lambda(Mo K-alpha) = 0.71073 angstrom, mu = 1.8 cm-1, F(000) = 1088, T = 288 K, R = 0.050 for 1512 observed reflections. The structure contains two 5-phenyldibenzophosphole molecules per asymmetric unit and these have almost identical conformations in the crystal lattice [as defined by the torsion angles C(11)-P(1A)-C(31)-C(32) 32.0(5) and C(41)-P(2A)-C(61)-C(62) 34.1(6)-degrees]. The central five-membered rings in both molecules have envelope conformations, with the P atom 0.136(15) and 0.104(15)angstrom from the relevant four-C-atom plane; the dibenzophosphole moieties are both bowed slightly, with the aromatic rings bent in a direction away from the pendant phenyl ring bonded to the P atom [dihedral angles between the plane of the C atoms of the central ring and the aromatic rings are in the range 1.1 (4)-3.0 (4)-degrees]. There is also a small rotation about the central C-C bond as shown by the relevant torsion angles which are in the range 0.2 (5)-3.3 (6)-degrees. Difference maps show that there is disorder in the crystal lattice in that each molecule is disordered over two sites [a major and a minor one in each case; occupancies 0.89 and 0.11 for molecule (1) and 0.95 and 0.05 for molecule (2)]. For the minor sites, only the P atoms could be detected. Main dimensions are: P-C(phenyl) 1.841 (9), 1.846 (10) angstrom, P-C(dibenzophosphole) 1.808 (9)-1.838 (10), mean 1.819 (9) angstrom, phosphole ring C-P-C 88.9 (4) and 89.5 (4)-degrees, exocyclic C-P-C 101.7 (4)-104.2 (4), mean 103.0 (4)-degrees.