N-(2-Formamidoethyl)formamide

The complete molecule of the title compound, C4H8N2O2, is generated by a crystallographic inversion center. The occurence of N—H⋯O hydrogen bonds results in the formation of a two-dimensional infinite network parallel to the (010) plane. In this plane, the hydrogen bonds define graph-set motif R 4 4(22) in a centrosymmetric array by the association of four molecules.

The complete molecule of the title compound, C 4 H 8 N 2 O 2 , is generated by a crystallographic inversion center. The occurence of N-HÁ Á ÁO hydrogen bonds results in the formation of a two-dimensional infinite network parallel to the (010) plane. In this plane, the hydrogen bonds define graph-set motif R 4 4 (22) in a centrosymmetric array by the association of four molecules.

Experimental
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: DN2396).
The molecule of (I) has a center of symmetry at the mid-point of the central C2-C2 i bond (Fig. 1).
Intermolecular N-H···O hydrogen bonds link the molecule to form a two dimensionnal network parallel to the (0 1 0) plane. In this plane, the hydrogen bonds define rings by associating 4 molécules displaying graph set motif R 4 4 (21) (Etter et al., 1990;Bernstein et al., 1995).

Therefore, the OH group of the starch can also form intermolecular O-H···O hydrogen bonds with the N-(2-
Formylaminoethyl)formamide, the mechanical properties of the plasticized starch is then enhanced.

Experimental
Methyl formate (500 ml) was placed in a 1000 ml flask cooled by ice-bath and ethylenediamine (250 ml) was slowly added. Subsequently, ice-bath was removed and the mixture was refluxed for 10 h. After standing overnight, the product was isolated by filtration. The solids obtained by filtration were recrystallized from anhydrous ethyl alcohol in 95% yield.
Colorless crystals of N-(2-Formylaminoethyl)formamide were obtained by slow evaporation of a solution of anhydrous methyl alcohol at 278 k(m.p. 381 k).

Refinement
The N-bound H atoms were located in a difference map and freely refined with U iso (H) = 1.2 U eq (N)], H atoms attached to carbon were positioned geometrically and treated as riding on their parent atoms [C-H distances are 0.93 Å for CH and 0.97 Å for CH 2 groups, both with U iso (H) = 1.2 U eq (C)]. Fig. 1. A view of the molecular structure of (I) with the atom-labeling scheme. Displacement ellopsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. [Symmetry code:(i) 1-x, 1-y, 1-z ]

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 Rfactors(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.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )