Two new thiophosphoramide structures: N,N′,N"-tricyclohexylphosphorothioic triamide and O,O′-diethyl (2-phenylhydrazin-1-yl)thiophosphonate

The compound N,N',N"-tricyclohexylphosphorothioic triamide, C18H36N3PS or P(S)[NHC6H11](3), (I), crystallizes in the space group Pnma with the molecule lying across a mirror plane; one N atom lies on the mirror plane, whereas the bond-angle sum at the other N atom has a deviation of some 8 degrees from the ideal value of 360 degrees for a planar configuration. The orientation of the atoms attached to this nonplanar N atom corresponds to an anti orientation of the corresponding lone electron pair (LEP) with respect to the P=S group. The P=S bond length of 1.9785 (6) angstrom is within the expected range for compounds with a P(S)[N](3) skeleton; however, it is in the region of the longest bond lengths found for analogous structures. This may be due to the involvement of the P=S group in N-H center dot center dot center dot S=P hydrogen bonds. In O,O'-diethyl (2-phenylhydrazin-1-yl)thiophosphonate, C10H17N2O2PS or P(S)[OC2H5](2)[NHNHC6H5], (II), the bond-angle sum at the N atom attached to the phenyl ring is 345.1 degrees, whereas, for the N atom bonded to the P atom, a practically planar environment is observed, with a bond-angle sum of 359.1 degrees. A Cambridge Structural Database [CSD; Allen (2002). Acta Cryst. B58, 380-388] analysis shows a shift of the maximum population of P=S bond lengths in compounds with a P(S)[O](2)[N] skeleton to the shorter bond lengths relative to compounds with a P(S)[N](3) skeleton. The influence of this difference on the collective tendencies of N center dot center dot center dot S distances in N-H center dot center dot center dot S hydrogen bonds for structures with P(S)[N](3) and P(S)[O](2)[N] segments were studied through a CSD analysis.