N,N′,N′′,N′′′-Tetrakis(2-methylphenyl)­oxybis(phospho­nic diamide): a redetermination at 150 K with Mo Kα radiation

The structure of the title compound, C(28)H(32)N(4)O(3)P(2), has been redetermined at 150 K, with much improved precision. The structure and mol-ecular packing of the title compound was previously determined using Cu Kα radiation, with an R value of 0.0933 [Cameron et al. (1978 ▶). Z. Naturforsch. Teil B, 33, 728-730]. The c-axis length in this structure [13.8401 (8) Å] is almost half that reported in the original study. In the title compound, two (C(6)H(4)(2-CH(3))NH)(2)P(O) units are bridged via an O atom [P-O-P = 133.31 (11)°]. The P atoms adopt a slightly distorted tetra-hedral coordination geometry. In the crystal, mol-ecules are linked via N-H⋯OP hydrogen bonds into extended chains parallel to the c axis. An intra-molecular N-H⋯O=P hydrogen bond is also found in the mol-ecule.