Three new [XC(O)NH]P(O)[N(CH2C6H5)2]2phosphoric triamides (X= CClF2, 3-F-C6H4and 3,5-F2-C6H3): a database analysis of tertiary N-atom geometry in compounds with a C(O)NHP(O)[N]2core

In the phosphoric triamidesN,N,N′,N′-tetrabenzyl-N′′-(2-chloro-2,2-difluoroacetyl)phosphoric triamide, C30H29ClF2N3O2P, (I),N,N,N′,N′-tetrabenzyl-N′′-(3-fluorobenzoyl)phosphoric triamide, C35H33FN3O2P, (II), andN,N,N′,N′-tetrabenzyl-N′′-(3,5-difluorobenzoyl)phosphoric triamide, C35H32F2N3O2P, (III), the tertiary N atoms of the dibenzylamido groups havesp2character with minimal deviation from planarity. The sums of the three bond angles about the N atoms in (I)–(III) deviate by less than 8° from the planar value of 360°. The geometries of the tertiary N atoms in all phosphoric triamides with C(O)NHP(O)[N]2skeletons deposited in the Cambridge Structural Database [CSD; Allen (2002).Acta Cryst.B58, 380–388] have been examined and the bond-angle sums at the two tertiary N atoms (SUM1 and SUM2) and the parameter ΔSUM (= SUM1 − SUM2) considered. It was found that in compounds with a considerable ΔSUM value, the more pyramidal N atoms are usually oriented so that the corresponding lone electron pair isantiwith respect to the P=O group. In (I), (II) and (III), the phosphoryl and carbonyl groups, separated by an N atom, areantiwith respect to each other. In the C(O)NHP(O) fragment of (I)–(III), the P—N bond is longer and the O—P—N angle is contracted compared with the other two P—N bonds and the O—P—N angles in the molecules. These effects are also seen in analogous compounds deposited in the CSD. Compounds with [C(O)NH]P(O)[N]X(X≠ N), such as compounds with a [C(O)NH]P(O)[N][O] skeleton, have not been considered here. Also, compounds with a [C(O)NH]2P(O)[N] fragment have not been reported to date. In the crystal structures of all three title compounds, adjacent molecules are linkedviapairs of P=O...H—N hydrogen bonds, forming dimers withCisymmetry.