research communications
E)-2-(thiophen-2-yl)ethenyl]-4,5-dihydropyridazin-3(2H)-one
Hirshfeld surface analysis and DFT studies of 6-[(aLaboratory of Applied Chemistry and Environment (LCAE), Faculty of Sciences, Mohamed I University, 60000 Oujda, Morocco, bDepartment of Physics, Faculty of Arts and Sciences, Ondokuz Mayıs, University, Samsun, Turkey, cLaboratory of Organic Synthesis, Extraction and Valorization, Faculty of Sciences, Ain Chok, University Hassan II, Casablanca, Rabat, Morocco, and dLaboratory of Plant Chemistry, Organic and Bioorganic Synthesis, URAC23, Faculty of Science, BP 1014, GEOPAC Research Center, Mohammed V University, Rabat, Morocco
*Correspondence e-mail: emineberrin.cinar@omu.edu.tr, fouadelkalai80@gmail.com, necmid@omu.edu.tr
In the title compound, C10H10N2OS, the five atoms of the thiophene ring are essentially coplanar (r.m.s. deviation = 0.0037 Å) and the pyridazine ring is non-planar. In the crystal, pairs of N—H⋯O hydrogen bonds link the molecules into dimers with an R22(8) ring motif. The dimers are linked by C—H⋯O interactions, forming layers parallel to the bc plane. The theoretical geometric parameters are in good agreement with XRD results. The intermolecular interactions were investigated using a Hirshfeld surface analysis and two-dimensional fingerprint plots. The Hirshfeld surface analysis of the title compound suggests that the most significant contributions to the crystal packing are by H⋯H (39.7%), C⋯H/H⋯C (17.3%) and O⋯H/H⋯O (16.8%) contacts.
1. Chemical context
Pyridazinone derivatives have been tested for their chemical and biological properties and achieved an increased interest in recent years (Akhtar et al., 2016). The pyridazinone moiety is known as a `wonder nucleus' as it can form diverse derivatives with many types of pharmacological activities such as antidepressant (Boukharsa et al., 2016), anti-HIV (Livermore et al., 1993), anti-inflammatory (Barberot et al., 2018), anticonvulsant (Partap et al., 2018), antihistaminic (Tao et al. 2012) and glucan synthase inhibition (Zhou et al., 2011) as well as acting as herbicidal agents (Asif, 2013). We report the synthesis and the crystal and molecular structure of the title compound (Fig. 1), as well as an analysis of its Hirshfeld surface and DFT studies.
2. Structural commentary
Selected geometrical parameters are given in Table 1. The five atoms of the thiophene ring are essentially coplanar (r.m.s. deviation = 0.0037 Å) while the pyridazine ring is non-planar with atom C2 furthest from the mean molecular plane at a distance of 0.610 (5) Å.
|
3. Supramolecular features
In the crystal, the molecules are connected pairwise through N—H⋯O hydrogen bonds (Table 2), forming dimers with an R22(8) graph set motif. The dimers are linked by C—H⋯O hydrogen bonds, forming layers parallel to the bc plane (Fig. 2). A packing diagram is shown in Fig. 2.
4. Database survey
A search of the Cambridge Structural Database (CSD, version 5.40, update November 2018; Groom et al., 2016) using (E)-6-(thiophen-2-yl)hex-5-enal and 6-vinyl-4,5-dihydropyridazin-3(2H)-one as the main skeleton found two structures similar to the title compound containing the pyridazine moiety with different substituents: 4-chloro-2-[(5-ethoxy-1,3,4-thiadiazol-2-yl)methyl]-5-(piperidin-1-yl)pyridazin-3(2H)-one (DOPZAL; Li et al., 2014) and 4-[(tert-butyldiphenylsilyloxy)methyl]pyridazin-3(2H)-one (CISPAX; Costas-Lago et al., 2013). In DOPZAL, the six atoms of the 1,6-dihydropyridazine ring are essentially coplanar (r.m.s. deviation = 0.008 Å), and the dihedral angle between this and the 1,3,4-thiadiazole ring is 62.06 (10)°. In CISPAX, pyridazinone moieties are anti-oriented across the Si—O bond [torsion angle = 168.44 (19)°]. In the crystal, molecules are assembled into inversion dimers through co-operative N—H⋯O hydrogen bonds between the NH groups and O atoms of the pyridazinone rings of neighbouring molecules.
5. Surface Analysis (SA)
The Hirshfeld surface analysis (Spackman & Jayatilaka, 2009) and the associated fingerprint plots were performed with CrystalExplorer17.5 (Turner et al., 2017). This software was used to analyse the intermolecular interactions in the crystal and to generate fingerprint plots mapped over dnorm, shape index and curvedness (Fig. 3). The Hirshfeld surface was calculated using a standard (high) surface resolution with the three-dimensional dnorm surface plotted over a fixed colour scale of −0.532 (red) to 1.345 (blue) a.u. The pale-red spots symbolize short contacts and negative dnorm values on the surface correspond to the N—H⋯O and C—H⋯O interactions (Table 2). The overall fingerprint plot and those delineated into H⋯H, H⋯C/ C⋯H, H⋯O/O⋯H, N⋯H/H⋯N and N⋯·C/C⋯·N contacts are shown in Fig. 4 along with their relative contributions to the Hirshfeld surface. The largest contribution is from H⋯H interactions (40.0%). The shape-index map of the title complex was generated in the range −1 to 1 Å, with the convex blue regions indicating hydrogen-donor groups and the concave red regions hydrogen-acceptor groups. The curvedness map, generated in the range −4 to 0.4 Å, shows large regions of green which denote a relatively flat surface area (planar), while the blue regions denote areas of curvature.
A view of the molecular electrostatic potential, in the range − 0.084 to 0.084 a.u. generated by the DFT method using the 6-31G(d,p) basis set is shown in Fig. 5. Here the N—H⋯O hydrogen-bond donors and acceptors are shown as blue and red areas around the atoms related with positive (hydrogen-bond donors) and negative (hydrogen-bond acceptors) electrostatic potentials, respectively.
The theoretical calculations were performed using GAUSSIAN03 (Frisch et al., 2004). The initial geometry was taken from the X-ray coordinates and this geometry was optimized using the DFT/B3LYP (Becke, 1993) method with LANL2DZ as the basis set. The theoretical geometrical parameters are in good agreement with XRD results (Table 1).
6. Frontier molecular orbitals
The highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbitals (LUMO) are known as frontier molecular orbitals (FMOs). The FMOs play an important role in the optical and electric properties. The frontier orbital gap can indicate the chemical reactivity and the kinetic stability of the molecule. If the energy gap is small then the molecule is highly polarizable and has high chemical reactivity. A molecule with a small frontier orbital gap is generally associated with a high chemical reactivity, low kinetic stability and is termed a soft molecule. Fig. 6 illustrates the HOMO and LUMO energy levels of the title compound. The small HOMO–LUMO energy gap of 2.41 eV in this compound indicates the chemical reactivity is strong and the kinetic stability is weak. A map of the electron density is shown in Fig. 7.
7. Synthesis and crystallization
To a solution of 4-oxo-6-(thiophen-2-yl)hex-5-enoic acid (0.21 g, 1 mmol) in 20 mL of ethanol, it was added an equimolar amount of hydrazine hydrate. The mixture was maintained under reflux for 4h, until TLC indicated the end of the reaction. The reaction mixture was poured into cold water, and the precipitate formed was filtered out, washed with ethanol and recrystallized from ethanol. Slow evaporation at room temperature led to formation of single crystals.
8. Refinement
Crystal data, data collection and structure . Hydrogen atoms were fixed geometrically and treated as riding, the C-bound H atoms were placed in idealized positions and refined as riding: C—H = 0.93 Å for methylene Uiso(H) = 1.5Ueq(C) and C—H = 0.97 Å for the other C atoms with Uiso(H) = 1.2Ueq(C). The NH H atom was located in a difference-Fourier map and freely refined.
details are summarized in Table 3Supporting information
https://doi.org/10.1107/S2056989019015147/mw2150sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989019015147/mw2150Isup2.hkl
Data collection: X-AREA (Stoe & Cie, 2002); cell
X-AREA (Stoe & Cie, 2002); data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SHELXT2015 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2015 (Sheldrick, 2015b); molecular graphics: PLATON (Spek, 2009) and Mercury (Macrae et al., 2008); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009).C10H10N2OS | F(000) = 432 |
Mr = 206.26 | Dx = 1.369 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 6.9932 (5) Å | Cell parameters from 6992 reflections |
b = 16.2916 (9) Å | θ = 2.3–30.0° |
c = 9.3544 (7) Å | µ = 0.29 mm−1 |
β = 110.168 (6)° | T = 296 K |
V = 1000.40 (12) Å3 | Stick, orange |
Z = 4 | 0.78 × 0.43 × 0.25 mm |
Stoe IPDS 2 diffractometer | 1971 independent reflections |
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus | 1394 reflections with I > 2σ(I) |
Plane graphite monochromator | Rint = 0.043 |
Detector resolution: 6.67 pixels mm-1 | θmax = 26.0°, θmin = 2.5° |
rotation method scans | h = −8→8 |
Absorption correction: integration (X-RED32; Stoe & Cie, 2002) | k = −20→19 |
Tmin = 0.767, Tmax = 0.932 | l = −11→11 |
6292 measured reflections |
Refinement on F2 | 19 restraints |
Least-squares matrix: full | Hydrogen site location: mixed |
R[F2 > 2σ(F2)] = 0.045 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.135 | w = 1/[σ2(Fo2) + (0.079P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.02 | (Δ/σ)max < 0.001 |
1971 reflections | Δρmax = 0.24 e Å−3 |
131 parameters | Δρmin = −0.34 e Å−3 |
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. |
x | y | z | Uiso*/Ueq | ||
S1 | 0.23031 (12) | 0.42526 (4) | 0.98925 (7) | 0.0768 (3) | |
O1 | 0.8844 (3) | 0.41724 (11) | 0.36257 (19) | 0.0752 (5) | |
N2 | 0.6910 (3) | 0.45665 (12) | 0.66000 (19) | 0.0559 (5) | |
N1 | 0.8097 (3) | 0.45451 (13) | 0.5682 (2) | 0.0581 (5) | |
C4 | 0.5618 (3) | 0.39839 (14) | 0.6440 (2) | 0.0521 (5) | |
C7 | 0.1949 (3) | 0.34895 (13) | 0.8563 (2) | 0.0517 (5) | |
C6 | 0.3065 (3) | 0.34666 (13) | 0.7517 (2) | 0.0535 (5) | |
H6 | 0.277544 | 0.303662 | 0.682065 | 0.064* | |
C5 | 0.4468 (3) | 0.40054 (14) | 0.7461 (2) | 0.0549 (5) | |
H5 | 0.473561 | 0.443933 | 0.814790 | 0.066* | |
C8 | 0.0484 (4) | 0.29384 (15) | 0.8660 (2) | 0.0607 (6) | |
H8 | 0.005051 | 0.248100 | 0.803758 | 0.073* | |
C1 | 0.7734 (3) | 0.41133 (14) | 0.4389 (2) | 0.0568 (6) | |
C2 | 0.5880 (4) | 0.35925 (15) | 0.3960 (2) | 0.0640 (6) | |
H2A | 0.607918 | 0.311934 | 0.339710 | 0.077* | |
H2B | 0.473610 | 0.390273 | 0.329261 | 0.077* | |
C3 | 0.5376 (4) | 0.33001 (16) | 0.5325 (3) | 0.0681 (6) | |
H3A | 0.398564 | 0.309944 | 0.499271 | 0.082* | |
H3B | 0.627316 | 0.285060 | 0.581438 | 0.082* | |
C10 | 0.0570 (4) | 0.38383 (19) | 1.0572 (3) | 0.0739 (7) | |
H10 | 0.023862 | 0.405884 | 1.137400 | 0.089* | |
C9 | −0.0260 (4) | 0.31634 (18) | 0.9828 (3) | 0.0713 (6) | |
H9 | −0.124891 | 0.286306 | 1.005625 | 0.086* | |
H1 | 0.902 (4) | 0.4897 (15) | 0.593 (2) | 0.058 (7)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.0979 (5) | 0.0736 (5) | 0.0729 (4) | −0.0147 (4) | 0.0476 (4) | −0.0139 (3) |
O1 | 0.0895 (12) | 0.0816 (12) | 0.0746 (10) | −0.0144 (10) | 0.0540 (9) | −0.0103 (8) |
N2 | 0.0594 (11) | 0.0619 (11) | 0.0527 (9) | −0.0040 (9) | 0.0272 (8) | −0.0029 (8) |
N1 | 0.0604 (11) | 0.0644 (12) | 0.0580 (10) | −0.0108 (10) | 0.0312 (9) | −0.0065 (9) |
C4 | 0.0534 (11) | 0.0535 (12) | 0.0522 (11) | 0.0012 (10) | 0.0216 (9) | −0.0007 (9) |
C7 | 0.0521 (11) | 0.0561 (13) | 0.0465 (10) | 0.0032 (10) | 0.0165 (9) | 0.0054 (9) |
C6 | 0.0573 (12) | 0.0530 (13) | 0.0542 (11) | 0.0002 (10) | 0.0242 (10) | −0.0016 (9) |
C5 | 0.0610 (12) | 0.0565 (13) | 0.0525 (11) | −0.0034 (11) | 0.0261 (9) | −0.0043 (9) |
C8 | 0.0651 (13) | 0.0659 (14) | 0.0543 (11) | −0.0087 (11) | 0.0249 (9) | 0.0049 (9) |
C1 | 0.0655 (13) | 0.0554 (13) | 0.0550 (11) | 0.0023 (11) | 0.0279 (10) | 0.0014 (9) |
C2 | 0.0696 (14) | 0.0668 (15) | 0.0599 (12) | −0.0052 (12) | 0.0281 (11) | −0.0118 (10) |
C3 | 0.0757 (15) | 0.0639 (15) | 0.0798 (15) | −0.0133 (12) | 0.0459 (13) | −0.0150 (12) |
C10 | 0.0869 (17) | 0.0885 (19) | 0.0583 (13) | 0.0085 (16) | 0.0403 (12) | 0.0062 (13) |
C9 | 0.0686 (14) | 0.0910 (18) | 0.0624 (12) | −0.0097 (13) | 0.0329 (10) | 0.0097 (12) |
S1—C10 | 1.691 (3) | C5—H5 | 0.9300 |
S1—C7 | 1.715 (2) | C8—C9 | 1.411 (3) |
O1—C1 | 1.227 (3) | C8—H8 | 0.9300 |
N2—C4 | 1.283 (3) | C1—C2 | 1.484 (3) |
N2—N1 | 1.385 (2) | C2—C3 | 1.515 (3) |
N1—C1 | 1.345 (3) | C2—H2A | 0.9700 |
N1—H1 | 0.83 (2) | C2—H2B | 0.9700 |
C4—C5 | 1.446 (3) | C3—H3A | 0.9700 |
C4—C3 | 1.495 (3) | C3—H3B | 0.9700 |
C7—C8 | 1.388 (3) | C10—C9 | 1.323 (4) |
C7—C6 | 1.448 (3) | C10—H10 | 0.9300 |
C6—C5 | 1.331 (3) | C9—H9 | 0.9300 |
C6—H6 | 0.9300 | ||
C10—S1—C7 | 92.31 (13) | O1—C1—C2 | 123.8 (2) |
C4—N2—N1 | 117.21 (18) | N1—C1—C2 | 114.77 (19) |
C1—N1—N2 | 127.1 (2) | C1—C2—C3 | 112.76 (18) |
C1—N1—H1 | 119.6 (16) | C1—C2—H2A | 109.0 |
N2—N1—H1 | 112.7 (16) | C3—C2—H2A | 109.0 |
N2—C4—C5 | 115.76 (19) | C1—C2—H2B | 109.0 |
N2—C4—C3 | 122.57 (19) | C3—C2—H2B | 109.0 |
C5—C4—C3 | 121.6 (2) | H2A—C2—H2B | 107.8 |
C8—C7—C6 | 127.6 (2) | C4—C3—C2 | 110.5 (2) |
C8—C7—S1 | 110.28 (16) | C4—C3—H3A | 109.5 |
C6—C7—S1 | 122.15 (16) | C2—C3—H3A | 109.5 |
C5—C6—C7 | 125.9 (2) | C4—C3—H3B | 109.5 |
C5—C6—H6 | 117.1 | C2—C3—H3B | 109.5 |
C7—C6—H6 | 117.1 | H3A—C3—H3B | 108.1 |
C6—C5—C4 | 126.5 (2) | C9—C10—S1 | 112.02 (19) |
C6—C5—H5 | 116.7 | C9—C10—H10 | 124.0 |
C4—C5—H5 | 116.7 | S1—C10—H10 | 124.0 |
C7—C8—C9 | 111.1 (2) | C10—C9—C8 | 114.3 (2) |
C7—C8—H8 | 124.4 | C10—C9—H9 | 122.9 |
C9—C8—H8 | 124.4 | C8—C9—H9 | 122.9 |
O1—C1—N1 | 121.4 (2) | ||
C4—N2—N1—C1 | 18.1 (3) | S1—C7—C8—C9 | −0.6 (2) |
N1—N2—C4—C5 | 177.40 (18) | N2—N1—C1—O1 | 176.4 (2) |
N1—N2—C4—C3 | 0.3 (3) | N2—N1—C1—C2 | −1.9 (3) |
C10—S1—C7—C8 | 0.74 (18) | O1—C1—C2—C3 | 152.4 (2) |
C10—S1—C7—C6 | −179.65 (18) | N1—C1—C2—C3 | −29.5 (3) |
C8—C7—C6—C5 | −179.7 (2) | N2—C4—C3—C2 | −30.2 (3) |
S1—C7—C6—C5 | 0.8 (3) | C5—C4—C3—C2 | 152.9 (2) |
C7—C6—C5—C4 | 179.0 (2) | C1—C2—C3—C4 | 43.3 (3) |
N2—C4—C5—C6 | −179.4 (2) | C7—S1—C10—C9 | −0.7 (2) |
C3—C4—C5—C6 | −2.3 (4) | S1—C10—C9—C8 | 0.5 (3) |
C6—C7—C8—C9 | 179.8 (2) | C7—C8—C9—C10 | 0.1 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1i | 0.83 (3) | 2.07 (3) | 2.899 (3) | 175 (2) |
C10—H10···O1ii | 0.93 | 2.61 | 3.505 (3) | 161 |
Symmetry codes: (i) −x+2, −y+1, −z+1; (ii) x−1, y, z+1. |
X-ray | DFT/B3LYP/LANL2DZ | |
S1—C10 | 1.691 (3) | 1.734 (7) |
O1—C1 | 1.227 (3) | 1.219 (9) |
N2—C4 | 1.283 (3) | 1.300 (2) |
N2—N1 | 1.385 (2) | 1.375 (6) |
N1—C1 | 1.345 (3) | 1.353 (0) |
C10—S1—C7 | 92.31 (13) | 91.705 (6) |
O1—C1—N1 | 121.4 (2) | 121.412 (2) |
C7—C6—C5—C4 | 179.0 (2) | 178.857 (8) |
N2—C4—C5—C6 | -179.4 (2) | 179.554 (8) |
Funding information
This study was supported by Ondokuz Mayıs University under project No. PYO·FEN1906.19.001.
References
Akhtar, W., Shaquiquzzaman, M., Akhter, M., Verma, G., Khan, M. F. & Alam, M. M. (2016). Eur. J. Med. Chem. 123, 256–281. Web of Science CrossRef CAS PubMed Google Scholar
Asif, M. (2013). Mini-Rev. Org. Chem. 10, 113–122. Web of Science CrossRef CAS Google Scholar
Barberot, C., Moniot, A., Allart-Simon, I., Malleret, L., Yegorova, T., Laronze-Cochard, M., Bentaher, A., Médebielle, M., Bouillon, J., Hénon, E., Sapi, J., Velard, F. & Gérard, S. (2018). Eur. J. Med. Chem. 146, 139–146. Web of Science CrossRef CAS PubMed Google Scholar
Becke, A. D. (1993). J. Chem. Phys. 98, 5648–5652. CrossRef CAS Web of Science Google Scholar
Boukharsa, Y., Meddah, B., Tiendrebeogo, R. Y., Ibrahimi, A., Taoufik, J., Cherrah, Y., Benomar, A., Faouzi, M. E. A. & Ansar, M. (2016). Med. Chem. Res. 25, 494–500. Web of Science CrossRef CAS Google Scholar
Costas-Lago, M. C., Costas, T., Vila, N. & Besada, P. (2013). Acta Cryst. E69, o1859–o1860. CSD CrossRef IUCr Journals Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Frisch, M. J., Trucks, G. W., Schlegel, H. B., Scuseria, G. E., Robb, M. A., Cheeseman, J. R., Montgomery, J. A. Jr, Vreven, T., Kudin, K. N., Burant, J. C., Millam, J. M., Iyengar, S. S., Tomasi, J., Barone, V., Mennucci, B., Cossi, M., Scalmani, G., Rega, N., Petersson, G. A., Nakatsuji, H., Hada, M., Ehara, M., Toyota, K., Fukuda, R., Hasegawa, J., Ishida, M., Nakajima, T., Honda, Y., Kitao, O., Nakai, H., Klene, M., Li, X., Knox, J. E., Hratchian, H. P., Cross, J. B., Bakken, V., Adamo, C., Jaramillo, J., Gomperts, R., Stratmann, R. E., Yazyev, O., Austin, A. J., Cammi, R., Pomelli, C., Ochterski, J. W., Ayala, P. Y., Morokuma, K., Voth, G. A., Salvador, P., Dannenberg, J. J., Zakrzewski, V. G., Dapprich, S., Daniels, A. D., Strain, M. C., Farkas, O., Malick, D. K., Rabuck, A. D., Raghavachari, K., Foresman, J. B., Ortiz, J. V., Cui, Q., Baboul, A. G., Clifford, S., Cioslowski, J., Stefanov, B. B., Liu, G., Liashenko, A., Piskorz, P., Komaromi, I., Martin, R. L., Fox, D. J., Keith, T., Al-Laham, M. A., Peng, C. Y., Nanayakkara, A., Challacombe, M., Gill, P. M. W., Johnson, B., Chen, W., Wong, M. W., Gonzalez, C. & Pople, J. A. (2004). GAUSSIAN03. Gaussian Inc., Wallingford, CT, USA. Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CrossRef IUCr Journals Google Scholar
Li, H., Ren, X., Li, Y. & Zhao, L. (2014). Acta Cryst. E70, o1113. CSD CrossRef IUCr Journals Google Scholar
Livermore, D., Bethell, R. C., Cammack, N., Hancock, A. P., Hann, M. M., Green, D., Lamont, R. B., Noble, S. A., Orr, D. C., Payne, J. P., Ramsay, M. V. J., Shingler, A. H. Smith, C., Storer, R., Williamson, C. & Willson, T. (1993). J. Med. Chem. 36, 3784–3794. CSD CrossRef CAS PubMed Web of Science Google Scholar
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. Web of Science CrossRef CAS IUCr Journals Google Scholar
Partap, S., Akhtar, M. J., Yar, M. S., Hassan, M. Z. & Siddiqui, A. A. (2018). Bioorg. Chem. 77, 74–83. Web of Science CrossRef CAS PubMed Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Spackman, M. A. & Jayatilaka, D. (2009). CrystEngComm, 11, 19–32. Web of Science CrossRef CAS Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Stoe & Cie (2002). X-AREA and X-RED32. Stoe & Cie GmbH, Darmstadt, Germany. Google Scholar
Tao, M., Aimone, L. D., Gruner, J. A., Mathiasen, J. R., Huang, Z., Lyons, J., Raddatz, R. & Hudkins, R. L. (2012). Bioorg. Med. Chem. Lett. 22, 1073–1077. Web of Science CrossRef CAS PubMed Google Scholar
Turner, M. J., McKinnon, J. J., Wolff, S. K., Grimwood, D. J., Spackman, P. R., Jayatilaka, D. & Spackman, M. A. (2017). Crystal Explorer17. University of Western Australia. https://hirshfeldsurface.net. Google Scholar
Zhou, G., Ting, P. C., Aslanian, R., Cao, J., Kim, D. W., Kuang, R., Lee, J. F., Schwerdt, J., Wu, H., Jason Herr, R., Zych, A. J., Yang, J., Lam, S., Wainhaus, S., Black, T. A., McNicholas, P. M., Xu, Y. & Walker, S. S. (2011). Bioorg. Med. Chem. Lett. 21, 2890–2893. Web of Science CrossRef CAS PubMed Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.