Crystal structure, Hirshfeld surface analysis and interaction energy calculation of 1-decyl-2,3-dihydro-1H-benzimidazol-2-one

The title molecule adopts an L-shaped conformation with a straight alkyl group. In the crystal, N—H⋯O hydrogen bonds form inversion dimers, which are connected into chains extending along the b-axis direction.

In continuation of our investigations on the synthesis, physico-chemical characterization and biological properties of novel N-substituted benzimidazol-2-one derivatives, we have ISSN 2056-9890 studied the reaction of 1-bromodecane with 1-isopropenyl-1H-1,3-benzimidazol-2(3H)-one under phase-transfer catalysis conditions (Saber et al., 2020b;Srhir et al., 2020), We report herein the synthesis, and the molecular and crystal structures along with the Hirshfeld surface analysis and the intermolecular interaction energies of the title compound, C 17 H 26 N 2 O, (I).

Structural commentary
The title molecule adopts an L-shaped conformation with the straight n-decyl chain arranged nearly perpendicular to the dihydrobenzimidazole portion, as indicated by the C1-N2-C8-C9 torsion angle of À75.91 (12) (Fig. 1). The dihydrobenzimidazole portion is not planar, as indicated by the dihedral angle of 1.20 (6) between the constituent planes.

Supramolecular features
In the crystal of (I), inversion dimers are formed by N1-H1Á Á ÁO1 hydrogen bonds (

Hirshfeld surface analysis
In order to visualize the intermolecular interactions in the crystal of the title compound, a Hirshfeld surface (HS) analysis (Hirshfeld, 1977) was carried out using Crystal Explorer 17.5 (Turner et al., 2017). A view of the threedimensional Hirshfeld surface of (I), plotted over d norm and the electrostatic potential map are shown in Fig. 4a and b, respectively. The shape-index of the HS reveals that there are nointeractions in (I), as shown in Fig. 4c Table 1 Hydrogen-bond geometry (Å , ).

Figure 2
A portion of one chain viewed along the c-axis direction with N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds depicted, respectively, by blue and black dashed lines. H atoms not involved in hydrogen bonding were omitted for clarity.

Figure 3
Packing viewed along the b-axis direction with hydrogen bonds depicted as in Fig. 2 and C-HÁ Á Á(ring) interactions by green dashed lines. H atoms not involved in hydrogen bonding were omitted for clarity.

Figure 1
The asymmetric unit of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.  Fig. 5b-i, respectively, together with their relative contributions to the Hirshfeld surface. The most important interaction is HÁ Á ÁH (Table 2) contributing 75.9% to the overall crystal packing, which is reflected in Fig. 5b as widely scattered points of high density due to the large hydrogen content of the molecule, with the tip at d e = d i = 1.08 Å . In the presence of C-HÁ Á Á interactions, the pair of characteristic wings are seen in the fingerprint plot ( Fig. 5c) delineated into HÁ Á ÁC/CÁ Á ÁH contacts (12.5% contribution;  View of the three-dimensional Hirshfeld surface of the title compound plotted over electrostatic potential energy in the range À0.0500 to 0.0500 a.u. using the STO-3 G basis set at the Hartree-Fock level of theory. (c) Hirshfeld surface of the title compound plotted over shape-index.

Figure 5
The full two-dimensional fingerprint plots for the title compound The Hirshfeld surface analysis confirms the importance of H-atom contacts in establishing the packing. The large number of HÁ Á ÁH, HÁ Á ÁC/CÁ Á ÁH and HÁ Á ÁO/OÁ Á ÁH interactions suggest that van der Waals interactions play the major role in the crystal packing (Hathwar et al., 2015).

Refinement
Crystal, data collection and refinement details are presented in Table 3. Hydrogen atoms were located in difference-Fourier maps and were freely refined.

1-Decyl-2,3-dihydro-1H-benzimidazol-2-one
Crystal data Extinction correction: SHELXL 2018/3 (Sheldrick, 2015b), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.0415 (17) 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 > 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.