Crystal structure and Hirshfeld surface analysis of 2-chloro-N-(4-methoxyphenyl)acetamide

The methoxy group lies very close to the plane of the phenyl ring while the acetamido group is twisted out of this plane. In the crystal, N—H⋯O and C—H⋯O hydrogen bonds form layers of molecules parallel to the ab plane. The layers are connected by C—H⋯Cl hydrogen bonds and C—H⋯π(ring) interactions, forming a three-dimensional structure.

In the title molecule, C 9 H 10 ClNO 2 , the methoxy group lies very close to the plane of the phenyl ring while the acetamido group is twisted out of this plane by 28.87 (5) . In the crystal, a three-dimensional structure is generated by N-HÁ Á ÁO, C-HÁ Á ÁO and C-HÁ Á ÁCl hydrogen bonds plus C-HÁ Á Á(ring) interactions. A Hirshfeld surface analysis of the intermolecular interactions was performed and indicated that CÁ Á ÁH/HÁ Á ÁC interactions make the largest contribution to the surface area (33.4%).

Figure 2
A portion of one layer of the crystal packing viewed along the c-axis direction with N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds depicted, respectively, by violet and black dashed lines. Non-interacting hydrogen atoms are omitted for clarity.

Figure 3
Packing viewed along the a-axis direction with N-HÁ Á ÁO, C-HÁ Á ÁO and C-HÁ Á ÁCl hydrogen bonds depicted, respectively by violet, black and light green dashed lines. C-HÁ Á Á(ring) interactions are depicted by brown dashed lines and non-interacting hydrogen atoms are omitted for clarity.

Figure 1
The molecular structure of the title molecule with labelling scheme and 50% probability ellipsoids.  , 1988). In general, the conformation of the haloacetamide portion is quite similar in all structures, as is the formation of infinite chains by N-HÁ Á ÁO hydrogen bonds and these are comparable to the features found in the title structure. In DELZIE and XABWEF, C-HÁ Á Á(ring) interactions assist in the packing, as also observed for the title molecule.

Hirshfeld surface analysis
The analysis was performed with CrystalExplorer 21.5

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2   The Hirshfeld surface of the title molecule with two adjacent molecules involved in the N-HÁ Á ÁO, hydrogen bonded chain and two involving the C1-H1AÁ Á ÁO2 hydrogen bonds. The former interaction is depicted by blue arrows and the latter by curved black lines.  riding contributions with isotropic displacement parameters fixed at 1.2U eq (C) (1.5 for the methyl group). The N-bound H atom was found in a difference-Fourier map and refined with a DFIX 0.91 0.01 instruction and an independent isotropic displacement parameter.

Special details
Experimental. The diffraction data were obtained from 7 sets of frames, each of width 0.5° in ω or φ, collected with scan parameters determined by the "strategy" routine in APEX3. The scan time was 6 sec/frame. 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 > 2sigma(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. H-atoms attached to carbon were placed in calculated positions (C-H = 0.95 -0.99 Å) and were included as riding contributions with isotropic displacement parameters 1.2 -1.5 times those of the attached atoms. That attached to nitrogen was placed in a location derived from a difference map and refined with a DFIX 0.91 0.01 instruction.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq