Diastereotopic groups in two new single-enanti-omer structures ()P(O)[NH-(+)CH(CH)(CH)] ( = OCH and CH).

The crystal structures of two single-enanti-omer compounds, diphenyl [()-(+)-α-ethyl-benzyl-amido]-phosphate, CHNOP or (CHO)P(O)[NH-()-(+)CH(CH)(CH)] (), and -[()-(+)-α-ethyl-benz-yl]-,-di-phenyl-phosphinic amide, CHNOP or (CH)P(O)[NH--(+)CH(CH)(CH)] (), were studied. The different environments at the phospho-rus atoms, (O)P(O)(N) and (C)P(O)(N), allow the P=O/P-N bond strengths to be compared, as well as the N-H⋯O=P hydrogen-bond strengths, and P=O/N-H vibrations. The following characteristics related to diastereotopic CHO/CH groups in / were considered: geometry parameters, contributions to the crystal packing, solution C/H NMR chemical shifts, conformations, and NMR coupling constants.

N,N-Dimethyl-N',N''-bis-(2-methyl-phenyl)phospho-ric triamide mono-hydrate.

In the title compound, C(16)H(22)N(3)OP·H(2)O, the P atom adopts a distorted tetra-hedral environment with the bond angles around the P atom in the range 99.98 (7)-116.20 (7)°.

N,N-Dimethyl-N',N''-diphenyl-phospho-ric triamide.

In the title compound, C(14)H(18)N(3)OP, a crystallographic mirror plane bis-ects the mol-ecule (the C,N,C atoms of the dimethyl-amido moiety and the P=O unit lie on the mirror plane). The P atom has a distorted tetra-hedral geometry; the bond angles at P are in the range 98.98 (11)-115.