Syntheses, spectroscopic study and crystal structures of some new N-benzoylphosphoric triamides

Three new phosphoric triamides with a [C(O)NH]P(O)[N(C)(C)]2 skeleton: a database analysis of C-N-C and P-N-C bond angles

In N,N,N',N'-tetraethyl-N''-(4-fluorobenzoyl)phosphoric triamide, C15H25FN3O2P, (I), and N-(2,6-difluorobenzoyl)-N',N''-bis(4-methylpiperidin-1-yl)phosphoric triamide, C19H28F2N3O2P, (II), the C-N-C angle at each tertiary N atom is significantly smaller than the two P-N-C angles. For the other new structure, N,N'-dicyclohexyl-N''-(2-fluorobenzoyl)-N,N'-dimethylphosphoric triamide, C21H33FN3O2P, (III), one C-N-C angle [117.08 (12)°] has a greater value than the related P-N-C angle [115.59 (9)°] at the same N atom. Furthermore, for most of the analogous structures with a [C(=O)NH]P(=O)[N(C)(C)]2 skeleton deposited in the Cambridge Structural Database [CSD; Allen (2002). Acta Cryst. B58, 380-388], the C-N-C angle is significantly smaller than the two P-N-C angles; exceptions were found for four structures with the N-methylcyclohexylamide substituent, similar to (III), one structure with the seven-membered cyclic amide azepan-1-yl substituent and one structure with an N-methylbenzylamide substituent. The asymmetric units of (I), (II) and (III) contain one molecule, and in the crystal structures, adjacent molecules are linked via pairs of N-H···O=P hydrogen bonds to form dimers.