A new phosphorothioic triamide structure: P(S)[NHCH sub(2)C sub(6)H sub(5)] sub(3)

The structure of N,N',N''-tribenzylphosphorothioic triamide, C sub(21)H sub(24)N sub(3)PS, (I), and analysis of the bond-angle sums at the N atoms for this compound, and for 74 structures with a P(S)[N] sub(3) skeleton and the N atom in a three-coordinate geometry found in the Cambridge Structural Database [CSD; Groom & Allen (2014). Angew. Chem. Int. Ed.53, 662-671], are reported. For (I), the bond-angle sum at one of the N atoms [359(1) degree ] shows a nearly planar configuration, while the other two show a nonplanar geometry with bond-angle sums of 342(1) and 347(1) degree . The location of the atoms attached to the nonplanar N atoms suggests an anti orientation of the corresponding lone electron pairs (LEPs) on these N atoms with respect to the P=S group. For 74 structures with a P(S)[N] sub(3) skeleton and with the N atom in a three-coordinate geometry, the bond-angle sums at the N atoms were found to be in the range 293-360 degree . Among 307 such three-coordinate N atoms, 39% (120 N atoms) have bond-angle sums in the range 359-360 degree , in accordance with sp super(2) hybridization, and 45% (138 N atoms) have bond-angle sums in the range 352-359 degree , with hybridization close to sp super(2). For the orientation of the LEP with respect to the P=S group, the anti orientation was found to be a general rule for N atoms, with the corresponding bond-angle sums deviating by more than 8 degree from the planar value of 360 degree . In the title structure, the S atom takes part in intermolecular (N-H...)(N-H...)S hydrogen bonds, connecting the molecules into extended chains parallel to the b axis. The co-operation of one N atom in an N-H...S hydrogen bond as an H-atom donor, and in an N-H...N hydrogen bond as an acceptor, is a novel feature of the crystal structure.