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ISSN: 2056-9890

Crystal structure, DFT calculation, Hirshfeld surface analysis and energy framework study of 6-bromo-2-(4-bromo­phen­yl)imidazo[1,2-a]pyridine

aDepartment of Studies in Physics, Manasagangotri, University of Mysore, Mysuru 570 006, Karnataka, India, bDepartment of Chemistry, Mangalore University, Mangalagangothri, Mangaluru 574 199, Karnataka, India, and cDepartment of Chemistry, Faculty of Science, Universiti Putra Malaysia 43400, UPM Serdang, Selangor Darul Ehsan, Malaysia
*Correspondence e-mail: mahendra@physics.uni-mysore.ac.in

Edited by M. Weil, Vienna University of Technology, Austria (Received 18 September 2019; accepted 30 September 2019; online 3 October 2019)

The title imidazo[1,2-a] pyridine derivative, C13H8Br2N2, was synthesized via a single-step reaction method. The title mol­ecule is planar, showing a dihedral angle of 0.62 (17)° between the phenyl and the imidazo[1,2-a] pyridine rings. An intra­molecular C—H⋯N hydrogen bond with an S(5) ring motif is present. In the crystal, a short H⋯H contact links adjacent mol­ecules into inversion-related dimers. The dimers are linked in turn by weak C—H⋯π and slipped ππ stacking inter­actions, forming layers parallel to (110). The layers are connected into a three-dimensional network by short Br⋯H contacts. Two-dimensional fingerprint plots and three-dimensional Hirshfeld surface analysis of the inter­molecular contacts reveal that the most important contributions for the crystal packing are from H⋯Br/Br⋯H (26.1%), H⋯H (21.7%), H⋯C/C⋯H (21.3%) and C⋯C (6.5%) inter­actions. Energy framework calculations suggest that the contacts formed between mol­ecules are largely dispersive in nature. Analysis of HOMO–LUMO energies from a DFT calculation reveals the pure π character of the aromatic rings with the highest electron density on the phenyl ring, and σ character of the electron density on the Br atoms. The HOMO–LUMO gap was found to be 4.343 eV.

1. Chemical context

Five-membered heterocyclic compounds comprising a nitro­gen atom and at least one other non-carbon atom (i.e. nitro­gen, sulfur, or oxygen) as part of the ring are known as azoles. To date, numerous azoles have found a wide range of applications in various fields, including agriculture (Berger et al., 2017[Berger, S., El Chazli, Y., Babu, A. F. & Coste, A. T. (2017). Front. Microbiol. 8, 1-6.]), and because of their biological activities (Pozharskii et al., 2011[Pozharskii, A. F., Soldatenkov, A. T. & Katritzky, A. R. (2011). Heterocycles in Life and Society. John Wiley & Sons.]; Kumbar et al., 2018[Kumbar, M. N., Kamble, R. R., Dasappa, J. P., Bayannavar, P. K., Khamees, H. A., Mahendra, M., Joshi, S. D., Dodamani, S., Rasal, V. P. & Jalalpure, S. (2018). J. Mol. Struct. 1160, 63-72.]). Among the various classes of azoles, the imidazole moiety with two nitro­gen atoms is extremely common in nature and forms the core of many biomolecules (Chopra & Sahu, 2019[Chopra, P. N. & Sahu, J. K. (2019). Curr. Drug Discov. Technol. 1, 1570-1638.]) and synthetic drugs (Pozharskii et al., 2011[Pozharskii, A. F., Soldatenkov, A. T. & Katritzky, A. R. (2011). Heterocycles in Life and Society. John Wiley & Sons.]). Furthermore, pyridine and its derivatives are present in many important compounds, including pharmaceuticals, vitamins (Al-Ghorbani et al., 2016[Al-Ghorbani, M., Thirusangu, P., Gurupadaswamy, H. D., Girish, V., Shamanth Neralagundi, H. G., Prabhakar, B. T. & Khanum, S. A. (2016). Bioorg. Chem. 65, 73-81.]) and drugs, acting as anti­microbial, anti­viral, anti­oxidants, anti­diabetic, anti-malarial, anti-inflammatory or anti­amoebic agents, as well as psychopharmacological antagonists (Altaf et al., 2015[Altaf, A. A., Shahzad, A., Gul, Z., Rasool, N., Badshah, A., Lal, B. & Khan, E. (2015). J. Drug Des. Med. Chem. 1, 1-11.]). Hence, the combination of pyridine and imidazole derivatives has been proven to result in highly active agents in diverse biological fields that include anti­cancer (Kamal et al., 2014[Kamal, A., Reddy, V. S., Santosh, K., Bharath Kumar, G., Shaik, A. B., Mahesh, R., Chourasiya, S. S., Sayeed, I. B. & Kotamraju, S. (2014). Med. Chem. Commun. 5, 1718-1723.]; Mantu et al., 2016[Mantu, D., Antoci, V., Moldoveanu, C., Zbancioc, G. & Mangalagiu, I. I. (2016). J. Enzyme Inhib. Med. Chem. 31, 96-103.]), anti-HIV (Bode et al., 2011[Bode, M. L., Gravestock, D., Moleele, S. S., van der Westhuyzen, C. W., Pelly, S. C., Steenkamp, P. A., Hoppe, H. C., Khan, T. & Nkabinde, L. A. (2011). Bioorg. Med. Chem. 19, 4227-4237.]), anti­bacterial (Rival et al., 1992[Rival, Y., Grassy, G. & Michel, G. (1992). Chem. Pharm. Bull. 40, 1170-1176.]) and anti-inflammatory (Rupert et al., 2003[Rupert, K. C., Henry, J. R., Dodd, J. H., Wadsworth, S. A., Cavender, D. E., Olini, G. C., Fahmy, B. & Siekierka, J. J. (2003). Bioorg. Med. Chem. Lett. 13, 347-350.]) properties. In addition, such a combination showed significant activity against the human cytomegalo virus and the varicella-zoster virus (Gueiffier et al., 1998[Gueiffier, A., Mavel, S., Lhassani, M., Elhakmaoui, A., Snoeck, R., Andrei, G., Chavignon, O., Teulade, J. C., Witvrouw, M., Balzarini, J., De Clercq, E. & Chapat, J. (1998). J. Med. Chem. 41, 5108-5112.]; Mavel et al., 2002[Mavel, S., Renou, J. L., Galtier, C., Allouchi, H., Snoeck, R., Andrei, G., De Clercq, E., Balzarini, J. & Gueiffier, A. (2002). Bioorg. Med. Chem. 10, 941-946.]).

[Scheme 1]

In this context, we synthesized a new imidazo[1,2-a] pyridine derivative, C13H8Br2N2, and report herein its mol­ecular and crystal structure, as well as the qu­anti­fication of supra­molecular inter­actions by Hirshfeld surface analysis. This study is supplemented by DFT calculations and a comparison of structural details with related compounds.

2. Structural commentary

The mol­ecular structure of the title compound is depicted in Fig. 1[link]. The mol­ecular system is planar, showing a dihedral angle of 0.62 (17)° between the phenyl ring (C1–C6) and the imidazo[1,2-a] pyridine ring system (C7–C13,N1,N2). The torsion angles about the terminal bromine atoms, Br1 and Br2, are 177.3 (3)° (Br1—C1—C6—C5) and −178.9 (4)° (Br2—C11—C12—C13), respectively. The planar arrangement between the two rings enables an intra­molecular C—H⋯N inter­action (Fig. 1[link], Table 1[link]) forming an S(5) ring motif (Tan & Tiekink, 2019[Tan, S. L. & Tiekink, E. R. T. (2019). Acta Cryst. E75, 1-7.]). The Br1—C1 and Br2—C11 bond lengths are 1.886 (4) Å and 1.880 (4) Å, respectively, in good agreement with structures comprising bromo­phenyl moieties (Zhang & Hu, 2005[Zhang, R. & Hu, Y. (2005). Acta Cryst. E61, o4037-o4038.]; Arif Tawfeeq et al., 2019[Arif Tawfeeq, N., Kwong, H. C., Mohamed Tahir, M. I. & Ravoof, T. B. S. A. (2019). Acta Cryst. E75, 774-779.]). The N1=C9 bond is slightly longer than similar bonds of reported imidazo[1,2-a] pyridine structures (see §7 for a listing of these structures), which may be attributed to the presence of the intra­molecular bond (H5⋯N1). Overall, the bond lengths and angles of the phenyl ring and the imidazo[1,2-a]pyridine ring system are in normal ranges and compare well with those of other imidazo[1,2-a]pyridine derivatives (Zhang et al., 2005[Zhang, R. & Hu, Y. (2005). Acta Cryst. E61, o4037-o4038.]; Dhanalakshmi et al., 2018[Dhanalakshmi, G., Ramanjaneyulu, M., Thennarasu, S. & Aravindhan, S. (2018). Acta Cryst. E74, 1913-1918.]).

Table 1
Hydrogen-bond geometry (Å, °)

Cg3 is the centroid of C1–C6 ring

D—H⋯A D—H H⋯A DA D—H⋯A
C5—H5⋯N1 0.93 2.47 2.827 (5) 103
C3—H3⋯Cg3i 0.93 2.91 3.5670 (1) 129
Symmetry code: (i) [x, -y-{\script{3\over 2}}, z-{\script{1\over 2}}].
[Figure 1]
Figure 1
The mol­ecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. The intra­molecular C—H⋯N hydrogen bond forming an S(5) ring motif is shown with dashed lines.

3. Supra­molecular features

The crystal packing is mainly based on short contacts and weak ππ inter­actions, similar to reported structures with the same kind of terminal bromine atoms (Arif Tawfeeq et al., 2019[Arif Tawfeeq, N., Kwong, H. C., Mohamed Tahir, M. I. & Ravoof, T. B. S. A. (2019). Acta Cryst. E75, 774-779.]). In the title compound, two inversion-related mol­ecules are linked by a short H5⋯H5(1 − x, 2 − y, z) contact (Fig. 2[link]). These dimers are connected to each other through C—H⋯π inter­actions (Table 1[link]), forming sheets propagating parallel to (110). Slipped ππ stacking inter­actions [Cg3⋯Cg1(−x, 1 − y, −z) = 3.655 (2) Å, slippage of 0.885 Å; Cg3⋯Cg2(−x, 1 − y, −z) = 3.819 (2) Å, slippage of 1.473 Å], where Cg1, Cg2 and Cg3 are the centroids of the imidazole, pyridine and phenyl rings, respectively, are also present within these sheets (Fig. 2[link]). Adjacent sheets are linked along [001] into a three-dimensional network through short contacts of 3.01 Å between Br1 and H12(x, [{3\over 2}] − y, [{1\over 2}] + z), forming S(11) chain motifs (Fig. 3[link]).

[Figure 2]
Figure 2
The crystal packing of the title compound in a view along [001], showing inter­actions in the sheets. H5⋯H5 short contacts are represented as blue dashed lines, C3—H3⋯Cg3 inter­actions as red dashed lines (slippage 1.676 Å) and Cg3⋯Cg1 and Cg3⋯Cg2 inter­actions as light-green dashed lines.
[Figure 3]
Figure 3
The three-dimensional supra­molecular network of the title compound viewed approximately along [010].

4. DFT study and FMOs

Density functional theory (DFT) calculations were carried out by using the B3LYP basis set (Becke, 1993[Becke, A. D. (1993). J. Chem. Phys. 98, 5648-5652.]) at the highest basis set level of 6-311 ++G(d,p) in the GAUSSIAN09 program (Frisch et al., 2009[Frisch, M. J., Trucks, G. W., Schlegel, H. B., Scuseria, G. E., Robb, M. A., Cheeseman, J. R., et al. (2009). GAUSSIAN09. Gaussian Inc., Wallingford, CT, USA.]). The DFT-optimized structure of the title compound is generally found to be in good agreement with the experimental data for all bond lengths and angles.

Frontier mol­ecular orbitals (FMOs) are useful to specify the distribution of electronic densities and other quantum chemical parameters including hardness (η), softness (ζ), chemical potential (μ), electrophilicity (ψ) and electronegativity (χ) by foreseeing the highest occupied mol­ecular orbitals (HOMO) and the lowest-unoccupied mol­ecular orbitals (LUMO), as well as the energy gap (Eg = EH - EL) (Khamees et al., 2018[Khamees, H. A., Jyothi, M., Khanum, S. A. & Madegowda, M. (2018). J. Mol. Struct. 1161, 199-217.]). The results of these calculations are compiled in Table 2[link], and orbital energy plots of (EH, EH-1) and (EL, EL+1) are depicted in Fig. 4[link]. The HOMO (ground state) manifests the highest π characterization for phenyl ring (C1–C6) that displays bifurcated ππ stacking inter­actions as well as C—H⋯π inter­actions in the supra­molecular network, as discussed in Section 3. Pronounced σ character of the electron density is located on the two Br atoms, with the higher amount located on Br1. The other FMOs orbitals, i.e. HOMO-1, LUMO and LUMO+1, exhibit a mix of π and σ character on the rings with variations of the electron density distribution (Fig. 4[link]). The HOMO–LUMO gap is 4.343 eV for the title compound.

Table 2
HUMO–LUMO energies and values of quantum chemical parameters (eV)

Property Symbol and formula Value
HOMO energy EH (eV) −6.234
LUMO energy EL (eV) −1.891
HOMO-1 energy EH-1 (eV) −6.552
LUMO+1 energy EL+1 (eV) −1.156
Energy gap 1 Eg1 = (EH - EL) (eV) 4.343
Energy gap 2 Eg2 = (EH-1 - EL+1) (eV) 5.397
Global hardness η = (EL - EH)/2 2.172
Softness ζ = 1/ 2η 0.230
Chemical potential μ = (EL + EH)/2 4.062
Electrophilicity ψ = μ2/2η 3.799
Electronegativity χ = -μ −4.062
[Figure 4]
Figure 4
Electron distribution and mol­ecular orbital energies of HOMO-1, HOMO, LUMO and LUMO+1 of the title compound.

5. Hirshfeld surface analysis

The nature of inter­molecular inter­actions in the title compound has been computed by CrystalExplorer17.5 (Turner et al., 2017[Turner, M. J., McKinnon, J. J., Wolff, S. K., Grimwood, D. J., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2017). CrystalExplorer17. University of Western Australia. http://hirshfeldsurface. net.]), using Hirshfeld surface analysis (Spackman & Jayatilaka, 2009[Spackman, M. A. & Jayatilaka, D. (2009). CrystEngComm, 11, 19-32.]) and two-dimensional fingerprint plots (McKinnon et al., 2007[McKinnon, J. J., Jayatilaka, D. & Spackman, M. A. (2007). Chem. Commun. pp. 3814-3816.]). The dnorm plot was estimated via calculations of the external (de) and inter­nal (di) distances to the nearest nucleus and built over the volume of 363.34 Å3 and an area of 339.81 Å2, with scaled colour of −0.1544 (red) a.u. to 1.0479 (blue) a.u. (Fig. 5[link]a). The plots of shape-index and curvedness were generated in the range of −4.0 to 4.0 a.u. and −1.00 to 1.00 a.u., respectively, (Fig. 5[link]b,c). The medium dark and side pale-red spots on the Hirshfeld surface (Fig. 5[link]a) symbolize the H5⋯H5 and Br1⋯H12 short contacts, respectively. The two-dimensional fingerprint plot for all contacts is depicted in Fig. 6[link]a. The H⋯Br/Br⋯H contacts make the largest contribution (26.1%) to the Hirshfeld surface (Fig. 6[link]b). These contacts also make a significant contribution to the crystal packing as the distance between the atoms involved is slightly less than their van der Waals radii (di + de ≃ 3.01 Å). The inter­atomic contacts of H⋯H inter­actions generated 22.7% of the Hirshfeld surface (Fig. 6[link]c), showing a short spike at diagonal axes di + de ≃ 2.24 Å < 2.4 Å, denoting H⋯H short contacts with another significant effect on the mol­ecular packing. The two symmetrical broad wings in Fig. 6[link]d belong to H⋯C/C⋯H contacts that represent 21.3% of total surface and indicate the presence of C—H⋯π inter­actions in the crystal packing, where di + de ≃ 2.77 Å < 2.90 Å. The proportion of H⋯N/N⋯H contacts is 7.9% of the Hirshfeld surface (Fig. 6[link]e) and they appear as two close wings pointing at a distance greater than the van der Waals radii of N and H atoms (di + de > 2.75Å), with no significant contribution towards the crystal packing of the title mol­ecule. The small contribution of the C⋯C contacts (6.5%) to the Hirshfeld surface appears as an intense triangle (Fig. 6[link]f) at di + de ≃ 3.6 Å, indicating ππ stacking inter­actions in the crystal packing. This type of stacking inter­action appears as a flat region on the curvedness (Fig. 5[link]c) and also on the shape-index as red and blue triangles on the rings (Fig. 5[link]b), in particular on the phenyl ring (C1–C6). The contributions from other contacts have negligible effects on the packing.

[Figure 5]
Figure 5
(a) Hirshfeld surface mapped over dnorm showing short contacts as green dashed lines, (b) shape-index map and (c) curvedness map showing regions of ππ inter­actions.
[Figure 6]
Figure 6
Two-dimensional fingerprint plots of the title mol­ecule with their relative contributions to the Hirshfeld surface.

6. Energy framework

Qu­anti­fication of energy framework energies is considered a powerful method for understanding the topology of the overall inter­actions of mol­ecules in the crystal. This method allowed us to calculate and compare different energy components, i.e. repulsion (E_rep), electric (E_ele), dispersion (E_dis), polarization (E_pol) and total (E_tot) energy based on the anisotropy of the topology of pairwise inter­molecular inter­action energies. CrystalExplorer17.5 (Turner et al., 2017[Turner, M. J., McKinnon, J. J., Wolff, S. K., Grimwood, D. J., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2017). CrystalExplorer17. University of Western Australia. http://hirshfeldsurface. net.]) was used to calculate the energy framework of the title compound by generating new wave functions using the DFT method under 3-21G basis set with exchange and potential functions (B3LYP) for a mol­ecular cluster environment for a 1×1×1 unit cell. The thickness of the cylinder radius indicates the grade of inter­actions and is directly related to the energy magnitude and offers information about the stabilization of the crystal packing. In order to avoid the crowdedness of less significant inter­action energies, we set the cylindrical radii with a cut-off value of 5 kJ mol−1 and a scale factor of 50 to all energy components. The benchmarked energies were scaled according to Mackenzie et al. (2017[Mackenzie, C. F., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2017). IUCrJ, 4, 575-587.]) while E_rep, E_ele, E_dis and E_pol were scaled as 0.618, 1.057, 0.740, 0.871, respectively (Edwards et al., 2017[Edwards, A. J., Mackenzie, C. F., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2017). Faraday Discuss. 203, 93-112.]). The results of the calculations revealed that dispersion inter­actions exhibit approximately chair-shaped energy topologies through the rings, having a maximum energy value of −180.558 kJ mol−1 (Fig. 7[link]). The other energy components have values of 62.232 kJ mol−1, −29.38 kJ mol−1 and −9.176 kJ mol−1 for repulsion, electrostatic and polarization energies, respectively. The small value of electrostatic energy is attributed to the absence of classical hydrogen bonds. The total inter­action energy that resulted from all four main components is −156.886 kJ mol−1 (Fig. 7[link]d).

[Figure 7]
Figure 7
Energy framework of the title mol­ecules viewed along [001], showing: (a) electrostatic, (b) dispersion, (c) total energy force diagrams and (d) the details of inter­action with colour-coded, symmetry operation (Symop) and distances between mol­ecular centroids (R) in Å.

7. Database survey

36 structures containing the 2-phenyl­imidazo[1,2-a]pyridine moiety with different substituents were found in a search of the Cambridge Structural Database (CSD, version 5.40, last update May 2019; Groom et al., 2016[Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171-179.]). The different substit­uents R1 (on the imidazo[1,2-a]pyridinyl ring) and R2 (on the phenyl ring) together with the dihedral angles between the mean planes of the corresponding imidazo[1,2-a]pyridinyl and phenyl rings (dihedral angle 1) are compiled in Table 3[link]. By comparing the substitution positions, the structures can be divided into `3-(substituted)imidazo[1,2-a]pyridin­yl' compounds and `non-3-(substituted)imidazo[1,2-a]pyridin­yl' compounds. In general, the 3-(substituted)imidazo[1,2-a]pyridinyl compounds have a greater dihedral angle 1 values (12.0–47.5°). This may arise from steric repulsion between the 3-(substituted) group and the phenyl ring. However, there are four outliers (KABMIM, MIXZOJ, MONREO and ZUSSAJ) whose dihedral angle 1 values are lower than 10°. Most of the non-3-(substituted)imidazo[1,2-a]pyridinyl compounds have dihedral angle 1 values between 0.7 and 12.5°, which indicates that the imidazo[1,2-a]pyridinyl rings are close to coplanar to their attached phenyl rings. Here, the outlier is JEBZEY where the imidazo[1,2-a]pyridinyl ring is attached to a di-ortho-substituted isophthalo­nitrile ring. The dihedral angle 1 is 46.4° in this structure.

Table 3
Comparison of structural details in related imidazo[1,2-a]pyridinyl derivatives containing phenyl rings

Dihedral angle 1 is the angle between the mean planes of imidazo[1,2-a]pyridinyl and phenyl rings. Two sets of dihedral angles 1 are stated for compounds HURZOL, MONREO, OMIDEV, RUJNEQ, TUZYEU, ZUSSAJ and VEGKAU because there are two mol­ecules in their asymmetric units.

Compound R1 R2 Dihedral angle 1
3-(Substituted)imidazo[1,2-a]pyridin­yl
AHOMIV (Liu et al., 2015[Liu, S., Xi, H., Zhang, J., Wu, X., Gao, Q. & Wu, A. (2015). Org. Biomol. Chem. 13, 8807-8811.]) 6-iodo-3-(methyl­sulfan­yl)-imidazo[1,2-a]pyridin­yl phen­yl 27.0
BEGTUE (Nair et al., 2012[Nair, D. K., Mobin, S. M. & Namboothiri, I. N. N. (2012). Org. Lett. 14, 4580-4583.]) ethyl (imidazo[1,2-a]pyridin-3-yl)acetate phen­yl 38.6
DABTEI (Koudad et al., 2015[Koudad, M., Elaatiaoui, A., Benchat, N., Saadi, M. & El Ammari, L. (2015). Acta Cryst. E71, o979-o980.]) 6-nitro­imidazo[1,2-a]pyridinyl-3-carbaldehyde 4-meth­oxy­phen­yl 34.0
DIDZUO (Dey et al., 2018[Dey, A., Singsardar, M., Sarkar, R. & Hajra, A. (2018). ACS Omega 3, 3513-3521.]) 3-chloro-7-methyl-imidazo[1,2-a]pyridin­yl phen­yl 28.0
ECEGEA (Ma et al., 2011[Ma, L., Wang, X., Yu, W. & Han, B. (2011). Chem. Commun. 47, 11333-11335.]) ethyl 8-methyl-imidazo[1,2-a]pyridinyl-3-carboxyl­ate phen­yl 44.2
HUPWIZ01 (Vega et al., 2011[Vega, D. R., Baggio, R., Roca, M. & Tombari, D. (2011). J. Pharm. Sci. 100, 1377-1386.]) N,N-dimethyl-2-(6-methyl-imidazo[1,2-a]pyridin-3-yl)acetamide 4-methyl­phen­yl 24.6
HURZOL (Yang et al., 2015[Yang, D., Yan, K., Wei, W., Li, G., Lu, S., Zhao, C., Tian, L. & Wang, H. (2015). J. Org. Chem. 80, 11073-11079.]) 6-methyl­imidazo[1,2-a]pyridin-3-yl thio­cyanate 3-chloro­phen­yl 33.8, 27.7
KABMIM (Yang et al., 2016[Yang, D., Yan, K., Wei, W., Liu, Y., Zhang, M., Zhao, C., Tian, L. & Wang, H. (2016). Synthesis, 48, 122-130.]) 6-methyl-3-nitro­soimidazo[1,2-a]pyridin­yl 3-chloro­phen­yl 6.8
MIXZOJ (Anaflous et al., 2008a[Anaflous, A., Albay, H., Benchat, N., El Bali, B., Dušek, M. & Fejfarová, K. (2008a). Acta Cryst. E64, o926.]) N-(imidazo[1,2-a]pyridin-3-yl)acetamide phen­yl 9.0
MIXZUP (Anaflous et al., 2008b[Anaflous, A., Albay, H., Benchat, N., El Bali, B., Dušek, M. & Fejfarová, K. (2008b). Acta Cryst. E64, o927.]) imidazo[1,2-a]pyridinyl-3-carbaldehyde phen­yl 28.6
MONREO (Velázquez-Ponce et al., 2013[Velázquez-Ponce, M., Salgado-Zamora, H., Jiménez-Vázquez, H. A., Campos-Aldrete, M. E., Jiménez, R., Cervantes, H. & Hadda, T. B. (2013). Chem. Cent. J. 7: 20.]) 3-nitro­soimidazo[1,2-a]pyridin­yl phen­yl 17.4, 4.9
NOGRIM (Marandi et al., 2014[Marandi, G., Saghatforoush, L., Mendoza-Meroño, R. & García-Granda, S. (2014). Tetrahedron Lett. 55, 3052-3054.]) 3-(t-butyl­amino)-imidazo[1,2-a]pyridinyl-8-carb­oxy­lic acid 3-nitro­phen­yl 16.8
OMIDEV (Samanta et al., 2016[Samanta, S., Jana, S., Mondal, S., Monir, K., Chandra, S. K. & Hajra, A. (2016). Org. Biomol. Chem. 14, 5073-5078.]) 3-iodo-8-methyl-imidazo[1,2-a]pyridin­yl phen­yl 36.1, 34.4
QUQSEC (Ravi et al., 2016[Ravi, C., Chandra Mohan, D. & Adimurthy, S. (2016). Org. Biomol. Chem. 14, 2282-2290.]) 6-methyl-3-(methyl­sulfan­yl)imidazo[1,2-a]pyridin­yl 4-chloro­phen­yl 38.1
RELQUW (Yan et al., 2012[Yan, R.-L., Yan, H., Ma, C., Ren, Z.-Y., Gao, X.-A., Huang, G.-S. & Liang, Y.-M. (2012). J. Org. Chem. 77, 2024-2028.]) 8-methyl-3-nitro­imidazo[1,2-a]pyridin­yl phen­yl 47.5
RUJNEQ (Li et al., 2009[Li, Y.-H., Liu, W.-Y., Gao, Y. & Wang, Y.-P. (2009). Acta Cryst. E65, o3192.]) imidazo[1,2-a]pyridinyl-3-carbaldehyde 4-chloro­phen­yl 34.6, 33.5
TUZYEU (Zhang et al., 2016[Zhang, M., Lu, J., Zhang, J.-N. & Zhang, Z.-H. (2016). Catal. Commun. 78, 26-32.]) 6-fluoro-3-nitro-imidazo[1,2-a]pyridin­yl phen­yl 43.8, 37.9
UTITEX (Chunavala et al., 2011[Chunavala, K. C., Joshi, G., Suresh, E. & Adimurthy, S. (2011). Synthesis, 2011, 635-641.]) ethyl 7-methyl­imidazo[1,2-a]pyridinyl-3-carboxyl­ate phen­yl 39.6
YEDHIY (Georges et al., 1993[Georges, G. J., Vercauteren, D. P., Evrard, G. H., Durant, F. V., George, P. G. & Wick, A. E. (1993). Eur. J. Med. Chem. 28, 323-335.]) 6-chloro-N,N-di­propyl­imidazo[1,2-a] pyridinyl-3-acetamide 4-chloro­phen­yl 15.2
ZUSSAJ (Xiao et al., 2015[Xiao, X., Xie, Y., Bai, S., Deng, Y., Jiang, H. & Zeng, W. (2015). Org. Lett. 17, 3998-4001.]) 3-chloro-imidazo[1,2-a]pyridin­yl 4-methyl­phen­yl 12.0, 0.3
Non-3-(substituted)imidazo[1,2-a]pyridin­yl
BISDUF (Kutniewska et al., 2018[Kutniewska, S. E., Jarzembska, K. N., Kamiński, R., Stasyuk, A. J., Gryko, D. T. & Cyrański, M. K. (2018). Acta Cryst. B74, 725-737.]) imidazo[1,2-a]pyridin­yl 2-hy­droxy-5-meth­oxy­phen­yl 6.0
BISFAN (Kutniewska et al., 2018[Kutniewska, S. E., Jarzembska, K. N., Kamiński, R., Stasyuk, A. J., Gryko, D. T. & Cyrański, M. K. (2018). Acta Cryst. B74, 725-737.]) imidazo[1,2-a]pyridin­yl 2-hy­droxy-4-bromo­phen­yl 4.2
CAJTIQ (Aslanov et al., 1983[Aslanov, L. A., Tafeenko, V. A., Paseshnichenko, K. A., Bundel, Y. G., Gromov, S. P. & Gerasimov, B. G. (1983). Zh. Strukt. Khim. 24, 115-123.]) 6-nitro-imidazo[1,2-a]pyridin­yl phen­yl 3.3
FEMQOF (Kurteva et al. 2012[Kurteva, V. B., Lubenov, L. A., Nedeltcheva, D. V., Nikolova, R. P. & Shivachev, B. L. (2012). Arkivoc, 13, 282-294.]) imidazo[1,2-a]pyridin­yl 4-meth­oxy­phen­yl 12.5
JEBZEY (Zhu et al., 2017[Zhu, X., Shen, X.-J., Tian, Z.-Y., Lu, S., Tian, L.-L., Liu, W.-B., Song, B. & Hao, X.-Q. (2017). J. Org. Chem. 82, 6022-6031.]) imidazo[1,2-a]pyridin­yl isophthalo­nitrile 46.4
MIQSUD (Jin et al., 2019[Jin, S., Xie, B., Lin, S., Min, C., Deng, R. & Yan, Z. (2019). Org. Lett. 21, 3436-3440.]) 2-(imidazo[1,2-a]pyridin-5-yl)propan-2-ol phen­yl 2.7
NAGGEH (Tafeenko et al., 1996[Tafeenko, V., Paseshnichenko, K. & Schenk, H. (1996). Z. Kristallogr. 211, 457-263.]) imidazo[1,2-a]pyridin­yl phen­yl 4.4
NONFOM (Mutai et al., 2008[Mutai, T., Tomoda, H., Ohkawa, T., Yabe, Y. & Araki, K. (2008). Angew. Chem. Int. Ed. 47, 9522-9524.]) imidazo[1,2-a]pyridin­yl 2-hy­droxy­phen­yl 6.7
NUBVUD (Seferoğlu et al., 2015[Seferoğlu, Z., Ihmels, H. & Şahin, E. (2015). Dyes Pigments, 113, 465-473.]) 7-methyl­imidazo[1,2-a]pyridin­yl 4-meth­oxy­phen­yl 0.7
NUBWAK (Seferoğlu et al., 2015[Seferoğlu, Z., Ihmels, H. & Şahin, E. (2015). Dyes Pigments, 113, 465-473.]) 7-methyl-imidazo[1,2-a]pyridin­yl phen­yl 5.3
QODZUG (Mutai et al., 2014[Mutai, T., Shono, H., Shigemitsu, Y. & Araki, K. (2014). CrystEngComm, 16, 3890-3895.]) imidazo[1,2-a]pyridinyl-6-carbo­nitrile 2-hy­droxy­phen­yl 2.8
TIDVIN (Donohoe et al., 2012[Donohoe, T. J., Kabeshov, M. A., Rathi, A. H. & Smith, I. E. D. (2012). Org. Biomol. Chem. 10, 1093-1101.]) 6-bromo-imidazo[1,2-a]pyridin­yl phen­yl 2.4
VEGKAU (Duan et al., 2006[Duan, G.-Y., Tu, C.-B., Sun, Y.-W., Zhang, D.-T. & Wang, J.-W. (2006). Acta Cryst. E62, o1141-o1142.]) imidazo[1,2-a]pyridin­yl 3-bromo-4-meth­oxy­phen­yl 12.2, 2.7
WUHKER (Aydıner et al., 2015[Aydıner, B., Yalçın, E., Ihmels, H., Arslan, L., Açık, L. & Seferoğlu, Z. (2015). J. Photochem. Photobiol. Chem. 310, 113-121.]) 7-methyl­imidazo[1,2-a]pyridin­yl 4-chloro­phen­yl 9.1
ZUNVOV (Stasyuk et al., 2016[Stasyuk, A. J., Bultinck, P., Gryko, D. T. & Cyrański, M. K. (2016). J. Photochem. Photobiol. Chem. 314, 198-213.]) imidazo[1,2-a]pyridin­yl 2-hy­droxy-4-florophen­yl 3.2
ZUPCOE (Stasyuk et al., 2016[Stasyuk, A. J., Bultinck, P., Gryko, D. T. & Cyrański, M. K. (2016). J. Photochem. Photobiol. Chem. 314, 198-213.]) imidazo[1,2-a]pyridin­yl 2-hy­droxy-4-meth­oxy­phen­yl 5.8

8. Synthesis and crystallization

5-Bromo­pyridin-2-amine (1.211 g, 0.007 mol) and phenacyl bromide (0.007 mol) were refluxed for 14 h in 50 ml of absolute ethanol. The progress of the reaction was monitored by thin layer chromatography using Merck alumina backed silica gel 60 F254. After completion of the reaction, the resulting product was poured into crushed ice to obtain a fine grained solid product that was filtered off, separated and dried. The crude product was then recrystallized from hot ethanol with a yield of ∼70%. The melting point of 345 K was determined in an open capillary and is uncorrected. IR (KBr, cm−1): 3080 (Ar C—H stretch), 2918 (aliphatic C—H stretch, 4-bromo­phenyl moiety), 1587 (C=N stretch), 1332 (C—N), 792 and 595 (C—Br). 1H NMR (400 MHz, DMSO, δ ppm): 7.37 (d, 1H, 5-bromo­pyridine moiety), 7.55 (d, 2H, 4-bromo­phenyl moiety), 7.56 (d, 1H, 5-bromo­pyridine moiety), 7.78 (d, 2H, 4-bromo­phenyl moiety), 8.37 (s, 1H, imidazole ring), 8.87 (s, 1H, 5-bromo­pyridine moiety).13C NMR (400 MHz, δ ppm): 145.13 (imidazo­pyridine carbon atom), 110.24, 119.82, 125.12 and 132.14 (four carbon atoms of 5-bromo­pyridine moiety), 123.12, 128.30, 132.11, and 132.32 (six carbon atoms of 4-bromo­phenyl moiety), 113.13 and 130.10 (two carbon atoms of imidazole ring). LC–Mass m/z 350 [M+], 352 [M+2], 354 [M+4]. Analysis calculated for C13H8Br2N2 (350): C, 44.36; H, 2.29; N, 7.96. Found: C, 44.31; H, 2.23; N, 7.92%.

9. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 4[link]. Hydrogen atoms were placed in calculated positions (C—H = 0.93 Å) and were included in the refinement in the riding-model approximation, with Uiso(H) set to 1.2Ueq(C). The reflection (002) was affected by the beam-stop and was removed from the refinement

Table 4
Experimental details

Crystal data
Chemical formula C13H8Br2N2
Mr 352.03
Crystal system, space group Orthorhombic, Pbca
Temperature (K) 293
a, b, c (Å) 14.1711 (4), 6.0546 (2), 27.7102 (8)
V3) 2377.54 (12)
Z 8
Radiation type Mo Kα
μ (mm−1) 6.80
Crystal size (mm) 0.15 × 0.14 × 0.14
 
Data collection
Diffractometer Bruker Kappa APEXII CCD
No. of measured, independent and observed [I > 2σ(I)] reflections 41143, 3485, 1726
Rint 0.100
(sin θ/λ)max−1) 0.704
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.047, 0.118, 1.00
No. of reflections 3485
No. of parameters 154
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.88, −0.49
Computer programs: APEX2 and SAINT (Bruker, 2016[Bruker (2016). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXT (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), SHELXL (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]), Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]), PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]) and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Computing details top

Data collection: APEX2 (Bruker, 2016); cell refinement: SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: Mercury (Macrae et al., 2008) and PLATON (Spek, 2009); software used to prepare material for publication: publCIF (Westrip, 2010).

6-Bromo-2-(4-bromophenyl)imidazo[1,2-a]pyridine top
Crystal data top
C13H8Br2N2Dx = 1.967 Mg m3
Mr = 352.03Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, PbcaCell parameters from 3485 reflections
a = 14.1711 (4) Åθ = 2.1–30.1°
b = 6.0546 (2) ŵ = 6.80 mm1
c = 27.7102 (8) ÅT = 293 K
V = 2377.54 (12) Å3Block, colourless
Z = 80.15 × 0.14 × 0.14 mm
F(000) = 1360
Data collection top
Bruker Kappa APEXII CCD
diffractometer
Rint = 0.100
ω and φ scanθmax = 30.1°, θmin = 2.1°
41143 measured reflectionsh = 1919
3485 independent reflectionsk = 88
1726 reflections with I > 2σ(I)l = 3938
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.047H-atom parameters constrained
wR(F2) = 0.118 w = 1/[σ2(Fo2) + (0.0442P)2 + 2.6166P]
where P = (Fo2 + 2Fc2)/3
S = 1.00(Δ/σ)max = 0.002
3485 reflectionsΔρmax = 0.88 e Å3
154 parametersΔρmin = 0.49 e Å3
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Br20.15325 (4)0.05914 (9)0.27691 (2)0.0700 (2)
Br10.12673 (4)0.88905 (10)0.68410 (2)0.0740 (2)
N20.1377 (2)0.3517 (6)0.40975 (12)0.0449 (8)
N10.0885 (2)0.6735 (6)0.44091 (12)0.0484 (9)
C70.1238 (3)0.5400 (6)0.47646 (14)0.0401 (9)
C10.1234 (3)0.7762 (8)0.62067 (15)0.0482 (11)
C110.1297 (3)0.2554 (7)0.32808 (15)0.0498 (11)
C40.1241 (3)0.6173 (7)0.52687 (15)0.0424 (9)
C120.0872 (3)0.4597 (8)0.31737 (16)0.0571 (12)
H120.0706030.4936920.2857600.069*
C80.1549 (3)0.3438 (8)0.45819 (15)0.0479 (10)
H80.1823240.2281900.4752660.058*
C30.1597 (3)0.4933 (7)0.56424 (16)0.0495 (10)
H30.1853350.3550550.5577500.059*
C60.0866 (3)0.9064 (7)0.58414 (16)0.0539 (11)
H60.0614101.0449440.5907520.065*
C130.0707 (3)0.6058 (8)0.35300 (15)0.0561 (12)
H130.0419770.7401950.3460480.067*
C20.1582 (3)0.5687 (8)0.61068 (16)0.0532 (11)
H20.1806520.4800010.6355580.064*
C50.0885 (3)0.8244 (7)0.53745 (15)0.0479 (10)
H50.0650630.9112650.5124850.057*
C90.0968 (3)0.5559 (7)0.40055 (15)0.0442 (10)
C100.1555 (3)0.2005 (7)0.37352 (15)0.0492 (11)
H100.1842020.0657120.3801420.059*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br20.0853 (4)0.0701 (4)0.0545 (3)0.0001 (3)0.0150 (3)0.0104 (2)
Br10.0737 (4)0.1022 (4)0.0460 (3)0.0056 (3)0.0062 (2)0.0110 (3)
N20.039 (2)0.047 (2)0.049 (2)0.0024 (16)0.0010 (15)0.0053 (16)
N10.051 (2)0.050 (2)0.044 (2)0.0047 (17)0.0001 (16)0.0062 (17)
C70.032 (2)0.042 (2)0.045 (2)0.0013 (19)0.0038 (17)0.0074 (18)
C10.041 (2)0.063 (3)0.040 (2)0.008 (2)0.0008 (18)0.004 (2)
C110.051 (3)0.052 (3)0.046 (2)0.002 (2)0.007 (2)0.002 (2)
C40.030 (2)0.047 (2)0.051 (2)0.0038 (18)0.0002 (18)0.005 (2)
C120.070 (3)0.060 (3)0.041 (2)0.002 (2)0.007 (2)0.013 (2)
C80.043 (2)0.055 (3)0.046 (2)0.002 (2)0.0061 (19)0.006 (2)
C30.046 (2)0.045 (2)0.058 (3)0.008 (2)0.001 (2)0.008 (2)
C60.051 (3)0.049 (3)0.062 (3)0.003 (2)0.004 (2)0.001 (2)
C130.067 (3)0.057 (3)0.044 (2)0.009 (2)0.005 (2)0.008 (2)
C20.047 (3)0.066 (3)0.046 (2)0.007 (2)0.0042 (19)0.008 (2)
C50.044 (2)0.051 (3)0.048 (2)0.006 (2)0.0076 (19)0.013 (2)
C90.044 (2)0.041 (2)0.048 (2)0.0035 (19)0.0013 (18)0.0050 (19)
C100.047 (3)0.042 (2)0.059 (3)0.002 (2)0.002 (2)0.000 (2)
Geometric parameters (Å, º) top
Br2—C111.880 (4)C4—C51.383 (6)
Br1—C11.886 (4)C12—C131.346 (6)
N2—C81.365 (5)C12—H120.9300
N2—C101.382 (5)C8—H80.9300
N2—C91.389 (5)C3—C21.366 (6)
N1—C91.331 (5)C3—H30.9300
N1—C71.369 (5)C6—C51.386 (6)
C7—C81.364 (6)C6—H60.9300
C7—C41.473 (6)C13—C91.401 (6)
C1—C21.378 (6)C13—H130.9300
C1—C61.385 (6)C2—H20.9300
C11—C101.353 (6)C5—H50.9300
C11—C121.407 (6)C10—H100.9300
C4—C31.375 (6)
C8—N2—C10131.2 (4)C2—C3—C4121.4 (4)
C8—N2—C9106.6 (3)C2—C3—H3119.3
C10—N2—C9122.2 (4)C4—C3—H3119.3
C9—N1—C7104.8 (3)C1—C6—C5118.1 (4)
C8—C7—N1111.4 (4)C1—C6—H6120.9
C8—C7—C4128.9 (4)C5—C6—H6120.9
N1—C7—C4119.7 (4)C12—C13—C9120.1 (4)
C2—C1—C6120.5 (4)C12—C13—H13119.9
C2—C1—Br1120.6 (3)C9—C13—H13119.9
C6—C1—Br1119.0 (4)C3—C2—C1120.0 (4)
C10—C11—C12121.9 (4)C3—C2—H2120.0
C10—C11—Br2119.9 (3)C1—C2—H2120.0
C12—C11—Br2118.2 (3)C4—C5—C6122.0 (4)
C3—C4—C5118.0 (4)C4—C5—H5119.0
C3—C4—C7122.8 (4)C6—C5—H5119.0
C5—C4—C7119.2 (4)N1—C9—N2111.0 (3)
C13—C12—C11119.8 (4)N1—C9—C13130.6 (4)
C13—C12—H12120.1N2—C9—C13118.3 (4)
C11—C12—H12120.1C11—C10—N2117.6 (4)
C7—C8—N2106.1 (4)C11—C10—H10121.2
C7—C8—H8127.0N2—C10—H10121.2
N2—C8—H8127.0
C9—N1—C7—C80.9 (5)C6—C1—C2—C32.4 (7)
C9—N1—C7—C4178.9 (4)Br1—C1—C2—C3176.7 (3)
C8—C7—C4—C31.1 (6)C3—C4—C5—C61.0 (6)
N1—C7—C4—C3179.1 (4)C7—C4—C5—C6179.9 (4)
C8—C7—C4—C5179.8 (4)C1—C6—C5—C41.2 (6)
N1—C7—C4—C50.0 (6)C7—N1—C9—N20.7 (4)
C10—C11—C12—C130.5 (7)C7—N1—C9—C13178.7 (5)
Br2—C11—C12—C13178.9 (4)C8—N2—C9—N10.3 (5)
N1—C7—C8—N20.8 (5)C10—N2—C9—N1178.8 (4)
C4—C7—C8—N2179.0 (4)C8—N2—C9—C13179.2 (4)
C10—N2—C8—C7179.3 (4)C10—N2—C9—C131.7 (6)
C9—N2—C8—C70.3 (4)C12—C13—C9—N1179.3 (5)
C5—C4—C3—C21.5 (6)C12—C13—C9—N21.4 (7)
C7—C4—C3—C2179.4 (4)C12—C11—C10—N20.8 (6)
C2—C1—C6—C51.8 (6)Br2—C11—C10—N2179.2 (3)
Br1—C1—C6—C5177.3 (3)C8—N2—C10—C11179.8 (4)
C11—C12—C13—C90.8 (7)C9—N2—C10—C111.4 (6)
C4—C3—C2—C12.2 (7)
Hydrogen-bond geometry (Å, º) top
Cg3 is the centroid of C1–C6 ring
D—H···AD—HH···AD···AD—H···A
C5—H5···N10.932.472.827 (5)103
C3—H3···Cg3i0.932.913.5670 (1)129
Symmetry code: (i) x, y3/2, z1/2.
HUMO–LUMO energies and values of quantum chemical parameters (eV) top
PropertySymbol and formulaValue
HOMO energyEH (eV)-6.234
LUMO energyEL (eV)-1.891
HOMO-1 energyEH-1 (eV)-6.552
LUMO+1 energyEL+1 (eV)-1.156
Energy gap 1Eg1 = (EH - EL) (eV)4.343
Energy gap 2Eg2 = (EH-1 - EL+1) (eV)5.397
Global hardnessη = (EL - EH)/22.172
Softnessζ = 1/ 2η0.230
Chemical potentialµ = (EL + EH)/24.062
Electrophilicityψ = µ2/2η3.799
Electronegativityχ = -µ-4.062
Comparison of structural details in related imidazo[1,2-a]pyridinyl derivatives containing phenyl rings top
Dihedral angle 1 is the angle between the mean planes of imidazo[1,2-a]pyridinyl and phenyl rings. Two sets of dihedral angles 1 are stated for compounds HURZOL, MONREO, OMIDEV, RUJNEQ, TUZYEU, ZUSSAJ and VEGKAU because there are two molecules in their asymmetric units.
CompoundR1R2Dihedral angle 1
3-(Substituted)imidazo[1,2-a]pyridinyl
AHOMIV (Liu et al., 2015)6-iodo-3-(methylsulfanyl)-imidazo[1,2-a]pyridinylphenyl27.0
BEGTUE (Nair et al., 2012)ethyl (imidazo[1,2-a]pyridin-3-yl)acetatephenyl38.6
DABTEI (Koudad et al., 2015)6-nitroimidazo[1,2-a]pyridinyl-3-carbaldehyde4-methoxyphenyl34.0
DIDZUO (Dey et al., 2018)3-chloro-7-methyl-imidazo[1,2-a]pyridinylphenyl28.0
ECEGEA (Ma et al., 2011)ethyl 8-methyl-imidazo[1,2-a]pyridinyl-3-carboxylatephenyl44.2
HUPWIZ01 (Vega et al., 2011)N,N-dimethyl-2-(6-methyl-imidazo[1,2-a]pyridin-3-yl)acetamide4-methylphenyl24.6
HURZOL (Yang et al., 2015)6-methylimidazo[1,2-a]pyridin-3-yl thiocyanate3-chlorophenyl33.8, 27.7
KABMIM (Yang et al., 2016)6-methyl-3-nitrosoimidazo[1,2-a]pyridinyl3-chlorophenyl6.8
MIXZOJ (Anaflous et al., 2008a)N-(imidazo[1,2-a]pyridin-3-yl)acetamidephenyl9.0
MIXZUP (Anaflous et al., 2008b)imidazo[1,2-a]pyridinyl-3-carbaldehydephenyl28.6
MONREO (Velázquez-Ponce et al., 2013)3-nitrosoimidazo[1,2-a]pyridinylphenyl17.4, 4.9
NOGRIM (Marandi et al., 2014)3-(t-butylamino)-imidazo[1,2-a]pyridinyl-8-carboxylic acid3-nitrophenyl16.8
OMIDEV (Samanta et al., 2016)3-iodo-8-methyl-imidazo[1,2-a]pyridinylphenyl36.1, 34.4
QUQSEC (Ravi et al., 2016)6-methyl-3-(methylsulfanyl)imidazo[1,2-a]pyridinyl4-chlorophenyl38.1
RELQUW (Yan et al., 2012)8-methyl-3-nitroimidazo[1,2-a]pyridinylphenyl47.5
RUJNEQ (Li et al., 2009)imidazo[1,2-a]pyridinyl-3-carbaldehyde4-chlorophenyl34.6, 33.5
TUZYEU (Zhang et al., 2016)6-fluoro-3-nitro-imidazo[1,2-a]pyridinylphenyl43.8, 37.9
UTITEX (Chunavala et al., 2011)ethyl 7-methylimidazo[1,2-a]pyridinyl-3-carboxylatephenyl39.6
YEDHIY (Georges et al., 1993)6-chloro-N,N-dipropylimidazo[1,2-a] pyridinyl-3-acetamide4-chlorophenyl15.2
ZUSSAJ (Xiao et al., 2015)3-chloro-imidazo[1,2-a]pyridinyl4-methylphenyl12.0, 0.3
Non-3-(substituted)imidazo[1,2-a]pyridinyl
BISDUF (Kutniewska et al., 2018)imidazo[1,2-a]pyridinyl2-hydroxy-5-methoxyphenyl6.0
BISFAN (Kutniewska et al., 2018)imidazo[1,2-a]pyridinyl2-hydroxy-4-bromophenyl4.2
CAJTIQ (Aslanov et al., 1983)6-nitro-imidazo[1,2-a]pyridinylphenyl3.3
FEMQOF (Kurteva et al. 2012)imidazo[1,2-a]pyridinyl4-methoxyphenyl12.5
JEBZEY (Zhu et al., 2017)imidazo[1,2-a]pyridinylisophthalonitrile46.4
MIQSUD (Jin et al., 2019)2-(imidazo[1,2-a]pyridin-5-yl)propan-2-olphenyl2.7
NAGGEH (Tafeenko et al., 1996)imidazo[1,2-a]pyridinylphenyl4.4
NONFOM (Mutai et al., 2008)imidazo[1,2-a]pyridinyl2-hydroxyphenyl6.7
NUBVUD (Seferoğlu et al., 2015)7-methylimidazo[1,2-a]pyridinyl4-methoxyphenyl0.7
NUBWAK (Seferoğlu et al., 2015)7-methyl-imidazo[1,2-a]pyridinylphenyl5.3
QODZUG (Mutai et al., 2014)imidazo[1,2-a]pyridinyl-6-carbonitrile2-hydroxyphenyl2.8
TIDVIN (Donohoe et al., 2012)6-bromo-imidazo[1,2-a]pyridinylphenyl2.4
VEGKAU (Duan et al., 2006)imidazo[1,2-a]pyridinyl3-bromo-4-methoxyphenyl12.2, 2.7
WUHKER (Aydıner et al., 2015)7-methylimidazo[1,2-a]pyridinyl4-chlorophenyl9.1
ZUNVOV (Stasyuk et al., 2016)imidazo[1,2-a]pyridinyl2-hydroxy-4-florophenyl3.2
ZUPCOE (Stasyuk et al., 2016)imidazo[1,2-a]pyridinyl2-hydroxy-4-methoxyphenyl5.8
Summary of short interatomic contacts (Å) top
ContactDistancesymmetry
H5···H52.24 1-x,2-y,-z
Br1···H123.01 x,3/2-y,-1/2+z

Acknowledgements

The authors thank the Sophisticated Analytical Instruments Facility (SAIF), IIT Madras, for providing single-crystal and spectroscopic data.

References

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