Crystal structure and Hirshfeld surface analysis of 1-(2-fluorophenyl)-1H-tetrazole-5(4H)-thione

In the crystal, molecules are linked by pairs of N—H⋯S hydrogen bonds, forming inversion dimers with an (8) ring motif. The dimers are linked by the offset face-to-face π–π stacking interactions.


Chemical context
Tetrazoles as an important class of five-membered heterocyclic compounds have been known for over a hundred years. The most common synthetic approach to construct tetrazoles, based on the reaction of nitriles with hydrazoic acid, was first discovered by Hantzsch & Vagt (1901). Up to know, most synthetic protocols comprise the cycloaddition of nitriles, thiocyanates or isothiocyanates with an azide moiety, under different conditions. Tetrazole derivatives have found a broad range of applications in medicinal chemistry (Wang et al., 2019;Gao et al., 2019;Arulmozhi et al., 2017), coordination chemistry (Askerov et al., 2018;Askerov et al., 2019a,b;Aromí et al., 2011) and material science (Frija et al., 2010;Lv et al., 2006). Numerous tetrazole-based synthetic compounds such as tomelukast, cefazolin, losartan, valsartan and alfentanil have already been used in medicinal practice.
As a result of the considerable interest in this field, significant developments in the synthesis of tetrazoles have been attained, which were recently reviewed (Neochoritis et al., 2019). As a further study of the chemistry of tetrazoles, herein we report the crystal structure and Hirshfeld surface analysis of the title compound. ISSN 2056-9890

Structural commentary
The molecule of the title compound ( Fig. 1) is non-planar. The five-membered 4-dihydro-5H-tetrazole ring (N1-N4/C5) is essentially planar, with a largest deviation of 0.005 (1) Å for N3. The dihedral angle between the mean planes of the tetrazole and benzene rings is 59.94 (8) . The bond dimensions are typical of similar compounds, with a distinct N2 N3 double bond.

Supramolecular features
In the crystal, molecules are linked by pairs of N-HÁ Á ÁS hydrogen bonds, forming centrosymmetric dimers with an R 2 2 (8) ring motif (see Fig. 2 and Table 1). The dimers are linked by the offset face-to-facestacking interactions between the benzene rings, which are characterized by intercentroid distances of 3.8963 (9) and 3.8964 (9) Å , and centroid-to-plane distances of 3.4589 (6) and 3.4578 (6) Å (Fig. 2). Neighbouring molecules within the stack are related by the c glide plane. The hydrogen bonds and stacking interactions link the molecules into layers parallel to (100). Other short intermolecular contacts are collected in Table 2.

Hirshfeld surface analysis
In order to investigate the intermolecular interactions in the crystal structure of the title compound in a visual manner, Hirshfeld surfaces (McKinnon et al., 2007) and their associated two-dimensional fingerprint plots (Spackman & McKinnon, 2002) were generated using CrystalExplorer17 (Turner et al., 2017). The shorter and longer contacts are indicated as red and blue spots, respectively, on the Hirshfeld surfaces, and contacts with distances approximately equal to the sum of the van der Waals radii are represented as white spots. The contribution of interatomic contacts (Table 2) to the d norm surface of the title compound is shown in Fig. 3. In Fig. 4, red and blue triangles can be seen on the shape-index surface, which indicate the presence ofstacking interactions in the crystal structure. Analysis of the two-dimensional fingerprint plots ( Crystal packing of the title compound viewed along the a-axis direction. Dashed lines indicate the N-HÁ Á ÁS hydrogen bonds, which form centrosymmetric dimers with an R 2 2 (8) ring motif, and the face-to-face stacking interactions, which connect the dimers into layers parallel to (100). Table 1 Hydrogen-bond geometry (Å , ). Symmetry code: (i) Àx þ 1; Ày þ 2; Àz þ 1.

Table 2
Summary of short interatomic contacts (Å ) in the title compound.

Figure 1
The molecular structure of the title compound, showing displacement ellipsoids drawn at the 50% probability level.

Figure 4
Hirshfeld surface of the title molecule plotted over shape-index. The crystal structure of ZEFKED shows pairs of C-HÁ Á ÁF hydrogen bonds forming inversion dimers, while in the crystal of ZEFKAZ, in addition to the C-HÁ Á ÁF hydrogen bonds that generate chains parallel to the b axis, there are C-HÁ Á Á interactions that link the chains to form layers parallel to the ab plane.
In the crystal of ZOZNEK, the molecules are linked by weak C-HÁ Á Á(phenyl) interactions, forming supramolecular chains extending along the c-axis direction. The crystal packing is further consolidated by intermolecular N-HÁ Á ÁS hydrogen bonds and by weak C-HÁ Á ÁS interactions, yielding double chains propagating along the a-axis direction.
In the crystal structure of MITMOU, the supramolecular assembly is formed mainly by (N,C)-HÁ Á Á(N,O) hydrogenbond interactions. Initially, strong N-HÁ Á ÁN hydrogen bonds link pairs of inversion-related molecules that act as slabs of infinite chains running along the [100] direction connected by a C-HÁ Á ÁO hydrogen bond. Along the [010] direction, neighbouring chains are further connected by weakinteractions between two arene rings of adjacent molecules.
The crystal structure of MITMIO is built by a combination of strong N-HÁ Á ÁO and N-HÁ Á ÁN hydrogen bonds, which form chains of molecules running along the [100] direction. Parallel inversion-related chains of molecules are further connected by weaker C-HÁ Á ÁO interactions to build the molecular architecture along the [001] direction. Weak C-HÁ Á ÁN interactions connect the molecules in order to complete the three-dimensional structure along the [010] direction.
In the crystal of PONWIA, the molecules are linked into chains by N-HÁ Á ÁO hydrogen bonds with R 2 1 (5) ring motifs. After the N-methylation of the PONWIA molecule, no hydrogen-bonding interactions were observed for structure PONWOG. The crystal structure of PONWOG shows a disorder due to a 180 flip of the benzothiophene ring system.
In the crystal of MESTAI, the asymmetric unit comprises two molecules with similar conformations. In the crystal, weak C-HÁ Á ÁF interactions form chains of molecules and the chains are stacked to form layers parallel to (101).
In JESTOR, molecules are linked principally by N-HÁ Á ÁN hydrogen bonds involving the amino NH 2 group and a triazole N atom, forming R 4 4 (20) and R 2 4 (10) rings that combine to give a three-dimensional network of molecules. The hydrogen bonding is supported by two different C-HÁ Á Á interactions from the tolyl ring to either a triazole ring or a tolyl ring in a neighboring molecule. In JESTUX, intermolecular hydrogen bonds and C-HÁ Á Á interactions generate R 3 4 (15) and R 4 4 (21) rings.

Synthesis and crystallization
To a solution of of NaN 3 (29 mmol) in 50 mL of H 2 O 2fluorophenylisothiocyanate (19.6 mmol) was added at 293 K. The reaction mixture was boiled for 2 h, cooled to 293 K; then the aqueous solution was filtered from undissolved impurities and a 10% aqueous solution of HCl was added to it with stirring to pH = 2. The precipitate of the title compound was filtered off, washed with water, and then the product was recrystallized from ethanol.

Refinement details
Crystal data, data collection and structure refinement details are summarized in Table 3. The C-bound H atoms were placed in calculated positions (0.93 Å ) and refined as riding with U iso (H) = 1.2U eq (C). The N-bound H atom was located in a difference map and refined isotropically.

Computing details
Data collection: APEX2 (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXT2014/5 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: PLATON (Spek, 2020). 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.