Crystal structure and Hirshfeld surface analysis of 5,7-diphenyl-1,2,3,5,6,7-hexahydroimidazo[1,2-a]pyridine-6,6,8-tricarbonitrile methanol monosolvate

In the crystal, O—H⋯N and N—H⋯O hydrogen bonds link pairs of molecules via two methanol molecules. These molecules are connected to each other by C—H⋯N hydrogen bonds and form columns along the a-axis direction.


Chemical context
Having a great methodological diversity, C-C and C-X (where X is a heteroatom) bond-forming reactions lie at the heart of synthetic organic chemistry (Khalilov et al., 2018a,b;Maharramov et al., 2019;Cheng & Mankad, 2020). They allow the construction of complex molecular structures and the introduction of various substituents. Nowadays, researchers are constantly trying to develop new methods in these directions for the syntheses of structurally diverse valuable molecular entities. These approaches have successfully found application in the building of carbo-and heterocyclic ring systems (Naghiyev et al., 2020;Mamedov et al., 2019). In heterocyclic ring systems, the use of nitrogen as a bridgehead atom is being assessed widely. Bridgehead nitrogen heterocycles incorporating an imidazole ring are widespread structural motifs in a diverse range of compounds having application in medicinal chemistry, coordination chemistry, catalysis and materials science (Asadov et al., 2016;Ma et al., 2017aMa et al., ,b, 2020Ma et al., , 2021Maharramov et al., 2010Maharramov et al., , 2018Mahmoudi et al., 2017Mahmoudi et al., , 2019Mahmudov et al., 2019Mahmudov et al., , 2020. Various synthetic drugs, such as soraprazan, alpidem, olprinone, saripidem, necopidem, minodronic acid, zolimidine and zolpidem containing the imidazo[1,2-a]pyridine moiety ( Fig. 1) have already been used in medical practice (Hosseini & Bayat, 2018). ISSN 2056-9890 In the framework of our ongoing structural studies (Naghiyev et al., 2021), herein we report the crystal structure and Hirshfeld surface analysis of the title compound, 5,7diphenyl-1,2,3,5,6,7-hexahydroimidazo[1,2-a]pyridine-6,6,8tricarbonitrile methanol monosolvate.
To further investigate and visualize the intermolecular interactions of the title compound, the CrystalExplorer program (Turner et al., 2017) was used. The interactions between the corresponding donor and acceptor atoms are visualized as bright-red spots on the Hirshfeld surface mapped over d norm (Fig. 6), corresponding to O1-HO1Á Á ÁN3, C7-H7Á Á ÁN3 and N2-H2NÁ Á ÁO1 hydrogen bonds. The other red spots correspond to weaker van der Waals interactions, of which the details are listed in Table 2.

Contact
Distance Symmetry operation 3.07 x, y, À1 + z In ADETUZ, the six-membered ring adopts a twist-boat conformation. The molecules form dimeric associations via inversion-generated pairs of N-HÁ Á ÁO hydrogen bonds. In BUDZAC, the fused pyridine ring adopts a twisted sofa conformation. The molecular structure features close intramolecular C-HÁ Á ÁN and C-HÁ Á ÁO hydrogen bonding.

Synthesis and crystallization
To a solution of benzylidenemalononitrile (0.78 g; 5.1 mmol) in ethanol (30 mL), ethylenediamine (0.31 g; 5.2 mmol) was added and the mixture was refluxed for 7 h. Then 25 mL of ethanol were removed from the reaction mixture, which was left overnight. The precipitated crystals were separated by filtration and recrystallized from methanol (yield 47%; m.p. 443-444 K

Refinement
Crystal data, data collection and structure refinement details are summarized in       Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > 2sigma(F 2 ) is used only for calculating -R-factor-obs 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.