Crystal structure and Hirshfeld surface analysis of 3-amino-1-oxo-2,6,8-triphenyl-1,2,7,8-tetrahydroisoquinoline-4-carbonitrile

The supramolecular structure of the compound is stabilized by a three-dimensional array of N—H⋯O and C—H⋯N hydrogen bonds and C—H⋯π interactions.

Owing to the above-mentioned value of tetrahydroisoquinolines, there have been significant developments in this class of compounds. Herein, and in the framework of our ongoing structural studies (Naghiyev et al., 2020a,b,c), we report the crystal structure and Hirshfeld surface analysis of the title compound, 3-amino-1-oxo-2,6,8-triphenyl-1,2,7,8tetrahydroisoquinoline-4-carbonitrile.

Supramolecular features
In the crystal, molecules are linked via N-HÁ Á ÁO and C-HÁ Á ÁN hydrogen bonds, forming a three-dimensional network (Table 1, Fig. 2). Furthermore, the crystal packing is dominated by C-HÁ Á Á interactions with a strong involvement of the phenyl hydrogens on C13 (H13) and C26 (H26) (

Hirshfeld surface analysis
The Hirshfeld surfaces and two-dimensional fingerprint plots were calculated using CrystalExplorer (McKinnon et al., 2007). Hirshfeld surfaces enable the visualization of intermolecular interactions with different colours and colour intensity representing short or long contacts and indicating the relative strength of the interactions. Fig. 4(a) and Fig. 4(b) show the front and back sides of the three-dimensional Hirshfeld surface of the title compound plotted over d norm in the range À0.4556 to 1.6207 a.u. Here, the bright-red spots appearing near O1 and N3 result from the N2-H2BÁ Á ÁO1 and C7-H7BÁ Á ÁN3 interactions, which play a significant role in the molecular packing of the title compound. The overall twodimensional fingerprint plot for the title compound and those delineated into HÁ Á ÁH, CÁ Á ÁH/HÁ Á ÁC, NÁ Á ÁH/HÁ Á ÁN and OÁ Á ÁH/HÁ Á ÁO contacts are illustrated in Fig. 5, together with their relative contributions to the Hirshfeld surface while details of the various contacts are given in Table 2 The molecular structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level. Table 1 Hydrogen-bond geometry (Å , ).

Figure 2
A view of the intermolecular N-HÁ Á ÁO and C-HÁ Á ÁN hydrogen bonds of the title compound down the b axis. H atoms not involved in hydrogen bonding have been omitted for clarity.

Database survey
[Symmetry codes: The centroids are defined in Table 1. Table 2 Summary of short interatomic contacts (Å ) in the title compound.

Contact
Distance Symmetry operation  The compound KUGLIK co-crystallizes with three water molecules in the asymmetric unit, which leads to the formation of intense hydrogen bonding in the crystal. In the crystal of POPYEB, molecules are packed in a herringbone manner parallel to (103) and (103) via weak C-HÁ Á ÁO and C-HÁ Á Á(ring) interactions. In the crystal of CARCOQ, molecules are linked by an O-HÁ Á ÁO hydrogen bond, forming chains propagating along the a-axis direction. The chains are linked by C-HÁ Á ÁF hydrogen bonds, forming layers lying parallel to the ab plane. In LAQKUL, there are two independent molecules in the asymmetric unit. The heterocyclic ring assumes a twisted boat conformation and N-HÁ Á ÁO interactions help to construct the three-dimensional network within the crystal packing. In AZUSOE, no classical hydrogen bonds norinteractions were found in the crystal structure.

Synthesis and crystallization
To a solution of 2-acetyl-5-oxo-N-3,5-triphenylpentanamide (5.1 mmol) in acetonitrile (40 ml) was added malononitrile (5.2 mmol). The solution was stirred for 5 min at room temperature, ethylenediamine (5.2 mmol) was added and the mixture refluxed for 4 h and cooled down to room temperature. The reaction product precipitated from the reaction mixture as pale-yellow single crystals, was collected by filtration and purified by recrystallization in ethanol/water solution (yield 70%, m.p. 554-556 K).