Synthesis, crystal structure and Hirshfeld surface analysis of N-(4-chlorophenyl)-5-cyclopropyl-1-(4-methoxyphenyl)-1H-1,2,3-triazole-4-carboxamide

The title compound was obtained via a two-step synthesis involving the enole-mediated click Dimroth reaction of 4-azidoanisole with methyl 3-cyclopropyl-3-oxopropanoate leading to the 5-cyclopropyl-1-(4-methoxyphenyl)-1H-1,2,3-triazole-4-carboxylic acid and subsequent acid amidation with 4-chloroaniline by 1,1′-carbonyldiimidazole (CDI). In the extended structure, two molecules arranged in a near coplanar position relative to the triazole ring planes are interconnected by N—H⋯N and C—H⋯N hydrogen bonds into a homodimer. The dimers are linked by C—H⋯O interactions into ribbons.

The title compound, C 19 H 17 ClN 4 O 2 , was obtained via a two-step synthesis involving the enol-mediated click Dimroth reaction of 4-azidoanisole with methyl 3-cyclopropyl-3-oxopropanoate leading to the 5-cyclopropyl-1-(4-methoxyphenyl)-1H-1,2,3-triazole-4-carboxylic acid and subsequent acid amidation with 4-chloroaniline by 1,1 0 -carbonyldiimidazole (CDI). It crystallizes in space group P2 1 /n, with one molecule in the asymmetric unit. In the extended structure, two molecules arranged in a near coplanar fashion relative to the triazole ring planes are interconnected by N-HÁ Á ÁN and C-HÁ Á ÁN hydrogen bonds into a homodimer. The formation of dimers is a consequence of the above interaction and the edge-to-face stacking of aromatic rings, which are turned by 58.0 (3) relative to each other. The dimers are linked by C-HÁ Á ÁO interactions into ribbons. DFT calculations demonstrate that the frontier molecular orbitals are well separated in energy and the HOMO is largely localized on the 4-chlorophenyl amide motif while the LUMO is associated with aryltriazole grouping. A Hirshfeld surface analysis was performed to further analyse the intermolecular interactions.

Supramolecular features
As shown in Fig. 2 and Table 2, the extended structure of the title compound is consolidated by a number of intermolecular interactions. Two molecules arranged in a near coplanar manner relative to the triazole ring planes are interconnected by N4-H4Á Á ÁN2 i and C19-H19Á Á ÁN2 i hydrogen bonds into a homodimer. Within the dimer, the edge-to-face stacked aromatic rings are tilted by 58.0 (3) . Atom O1 of the amide group accepts both an intramolecular C-HÁ Á ÁO link (with the 4-chlorophenyl and cyclopropyl H atoms) and an intermolecular C2-H2Á Á ÁO1 interaction with the 4-methoxyphenyl H atom. The last of these links neighbouring dimers  Table 1 Hydrogen-bond geometry (Å , ). Symmetry codes: (i) Àx þ 1; Ày; Àz þ 1; (ii) Àx þ 1; Ày þ 1; Àz þ 1.

Figure 2
The hydrogen bonding of molecules in the title compound. Hydrogen bonds are shown as dashed lines. The symmetry codes are as in Table 1.

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

Hirshfeld surface analysis and computational study
Hirshfeld surface analysis was used to analyse the various intermolecular interactions in the title compound, through mapping the normalized contact distance (d norm ) using Crys-talExplorer (Turner et al., 2017;Spackman & Jayatilaka, 2009). Hirshfeld surfaces enable the visualization of intermolecular interactions by using different colours and colour intensity to represent short or long contacts and indicate the relative strength of the interactions. The most prominent interactions (the ortho-proton of the aryltriazole moiety and the carbonyl group as well as bifurcated interactions among protons of the amide group and the ortho-proton of the aryl group with the triazole ring nitrogen (N2) atoms of neighbouring molecules) can be seen in the Hirshfeld surface plot as red areas (Fig. 4). Fingerprint plots were produced to show the intermolecular surface bond distances with the regions highlighted for (C)HÁ Á ÁO and (C, N)HÁ Á ÁN interactions (Fig. 4). The contribution to the surface area for such contacts are 11.6% and 10.8%, respectively. The frontier molecular orbitals HOMO and LUMO were analysed to better understand the electronic charge transfer within the molecule and its electron donating and accepting ability. The molecular orbital energies were calculated using the B3LYP functional level with the 6-31+G* basis set in a vacuum with GAMESS software (Schmidt et al., 1993). The HOMO and LUMO orbitals were found to be well separated in energy and largely localized on the 4-chlorophenyl amide or aryltriazole motifs, respectively (Fig. 5). Their respective energy values were estimated to be À5.9 eV and À0.8 eV.
Compounds (I) and (II) crystallize in the monoclinic crystal system [non-centrosymmetric space group P2 1 in (I) and centrosymmetric P2 1 /c in (II)], while compounds (III) and (IV) crystallize in the triclinic space group P1. Structure (I) contains two crystallographically independent molecules, the hydroxyl groups of which participate in intermolecular O-HÁ Á ÁO hydrogen bonds. In contrast to the structure of title compound, the dihedral angles between the phenyl rings and triazole rings in (I) are À45.2 (6) (C5-C6-N1-N2) and 39.9 (6) (C1 0 -C6 0 -N1 0 -N2 0 ). The analogous angle in (II) is 19.2 (2) . In structure (II), the carboxamide groups connect neighbouring molecules into infinite hydrogen-bonded chains by means of N-HÁ Á ÁO hydrogen bonds: these are linked by N-HÁ Á ÁO (oxazole) contacts into a three-dimensional framework. Similarly to (I) and (II), structure (III) contains a 5-methyl substituent at the triazole ring and, because of significant steric hindrance of the 8-(trifluoromethyl)quinoline group, the dihedral angle between the rings is 54.7 . The phenyl and triazole rings in (IV) are close to coplanar (7.5 ), while the hydroxyl, carboxamide and amino groups participate   Frontier molecular orbital energies.

Figure 3
A view along the a axis of the crystal packing of the title compound. are monoclinic, space group C2/c. In both structures, the N-allyl-1H-1,2,3-triazole-4-carboxamide moiety acts as a bridging chelating ligand and forms, with the copper(I) atoms, infinite chains containing [CuC 4 NO] seven-membered rings.

N-(4-Chlorophenyl)-5-cyclopropyl-1-(4-methoxyphenyl)-1H-1,2,3-triazole-4-carboxamide
Crystal data 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.