A second monoclinic polymorph of N-[bis(morpholin-4-yl)phosphinoyl]-4-fluorobenzamide with the P21/n space group

A second monoclinic polymorph of the title molecule, C15H21FN3O4P, is reported in the space group P21/n and compared to the previously reported C2/c space group [Gholivand et al. (2006 ▶). Polyhedron, 25, 711–721]. The asymmetric unit of the title compound consists of two independent molecules. The P atoms adopt a distorted tetrahedral environment. In the C(O)NHP(O) fragment, the P=O and the N—H groups are in a syn conformation with respect to each other and in the crystal, intermolecular N—H⋯O=P hydrogen bonds form dimeric aggregates.

A second monoclinic polymorph of the title molecule, C 15 H 21 FN 3 O 4 P, is reported in the space group P2 1 /n and compared to the previously reported C2/c space group [Gholivand et al. (2006). Polyhedron,25,[711][712][713][714][715][716][717][718][719][720][721]. The asymmetric unit of the title compound consists of two independent molecules. The P atoms adopt a distorted tetrahedral environment. In the C(O)NHP(O) fragment, the P O and the N-H groups are in a syn conformation with respect to each other and in the crystal, intermolecular N-HÁ Á ÁO P hydrogen bonds form dimeric aggregates.

Related literature
For the monoclinic polymorph of the title molecule, in a C2/c space group, for bond lengths and angles and for preparation of the starting compound 4-F-C 6 H 4 C(O)NHP(O)Cl 2 , see: Gholivand et al. (2006) Table 1 Hydrogen-bond geometry (Å , ).
The P═O, C═O and P-N bond lengths and P-N-C bond angles are within the expected values (Gholivand et al., 2006).
In the crystal, two different intermolecular N-H···O(P) hydrogen bonds make dimeric aggregates. So, each hydrogenbonded dimer is built of two symmetrically independent molecules (Fig. 2).
Experimental 4-F-C 6 H 4 C(O)NHP(O)Cl 2 was prepared according to the literature method reported by Gholivand et al. (2006).
To a solution of 4-F-C 6 H 4 C(O)NHP(O)Cl 2 (0.723 g, 2.825 mmol) in dry acetonitrile (25 ml), a solution of morpholine (0.984 g, 11.300 mmol) in dry acetonitrile (5 ml) was added at 273 K. After 4 h stirring, the solvent was removed and the product was washed with distilled water and the resulting precipitate of 4-F-C 6 H 4 C(O)NHP(O)(NC 4 H 8 O) 2 was collected. Single crystals were obtained in a try on a reaction between 4-F-C 6 H 4 C(O)NHP(O)(NC 4 H 8 O) 2 and Sn(CH 3 ) 2 Cl 2 in CH 3 OH under reflux, followed by slow evaporation of the filtered solution at room temperature.

Refinement
All non-hydrogen atoms were refined anisotropically by full matrix least squares on F 2 . Hydrogen atoms H1N and H4N were found from a Fourier difference map and their N-H distances were fixed at 0.87 (2) Å and were allowed to refine isotropically with 1.20 U eq of parent N atoms. All other hydrogen atoms were placed in calculated positions and treated as riding on their parent C atoms with distances C-H = 0.990 Å (CH 2 ) and 1.00 Å (CH) with 1.20U eq of their parent C atoms.

N-[Bis(morpholin-4-yl)phosphinoyl]-4-fluorobenzamide
Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.