research communications\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

Crystal structure of 4-(4-chloro­phen­yl)-6-(morpholin-4-yl)pyridazin-3(2H)-one

aDepartment of Science Education, Faculty of Education, Kastamonu University, 37200 Kastamonu, Turkey, bDepartment of Physics, Faculty of Sciences, Erciyes University, 38039 Kayseri, Turkey, cDepartment of Pharmaceutical Chemistry, Faculty of Pharmacy, Gazi University, 06330 Ankara, Turkey, and dDepartment of Physics, Faculty of Arts and Sciences, Ondokuz Mayıs University, 55139 Samsun, Turkey
*Correspondence e-mail: aaydin@kastamonu.edu.tr

Edited by C. Rizzoli, Universita degli Studi di Parma, Italy (Received 30 June 2015; accepted 6 July 2015; online 17 July 2015)

In the title compound, C14H14ClN3O2, the morpholine ring adopts a chair conformation, with the exocyclic N—C bond in an equatorial orientation. The 1,6-di­hydro­pyridazine ring is essentially planar, with a maximum deviation of 0.014 (1) Å, and forms a dihedral angle of 40.16 (7)° with the plane of the benzene ring. In the crystal, pairs of centrosymmetrically related mol­ecules are linked into dimers via N—H⋯O hydrogen bonds, forming R22(8) ring motifs. The dimers are connected via C—H⋯O and C—H⋯Cl hydrogen bonds, forming a three-dimensional network. Aromatic ππ stacking inter­actions [centroid–centroid distance = 3.6665 (9) Å] are also observed. Semi-empirical mol­ecular orbital calculations were carried out using the AM1 method. The calculated dihedral angles between the pyridizine and benzene rings and between the pyridizine and morpholine (all atoms) rings are 34.49 and 76.96°, respectively·The corresponding values obtained from the X-ray structure determination are 40.16 (7) and 12.97 (9)°, respectively. The morpholine ring of the title compound in the calculated gas-phase seems to have a quite different orientation compared to that indicated by the X-ray structure determination.

1. Chemical context

The title compound was first synthesized by Şüküroğlu et al. (2006[Şüküroğlu, M., Küpeli, E., Banoğlu, E., Ünlü, S., Yeşilada, E. & Şahin, M. F. (2006). Arzneim. Forsch. Drug Res. 56, 337-345.]). The pharmacological properties of the compound have been investigated and it was found it possesses an analgesic effect close to that of aspirin. In recent years, the 3(2H)-pyridazinone system has aroused a great deal of attention due to its structural relationship to pyrazolone derivatives such as amino­pyrine and dipyrone in view of the ring enlargement of pyrazolone to pyridazinone. These drugs possess analgesic and anti-inflammatory activities although they have limitations for their clinical use due to serious side effects such as blood dyscrasias (Şüküroğlu et al., 2006[Şüküroğlu, M., Küpeli, E., Banoğlu, E., Ünlü, S., Yeşilada, E. & Şahin, M. F. (2006). Arzneim. Forsch. Drug Res. 56, 337-345.]; Brogden, 1986[Brogden, R. N. (1986). Drugs, 32, 60-70.]).

[Scheme 1]

2. Structural commentary

In the title compound (Fig. 1[link]) the morpholine ring (N3/O2/C11–C14) adopts a chair conformation, with the puckering parameters QT = 0.551 (2) Å, θ = 174.33 (19) and φ = 175 (2)°. The 1,6-di­hydro­pyridazine ring (N1/N2/C7–C10) is essentially planar, with a maximum deviation of 0.014 (1) Å for atom N1 and forms a dihedral angle of 40.16 (7)° with the C1–C6 benzene ring. The dihedral angle between the morpholine ring (all atoms) and the pyridizine ring is 12.97 (9)°. The bond lengths and angles are in the normal range. The Cl1—C4, N1—N2 and O1—C12 bond lengths [1.7379 (17), 1.3620 (16), and 1.417 (3) Å, respectively] are consistent with those reported previously [1.753 (5), 1.275 (7) and 1.432 (7) Å in mol­ecule A; Aydin et al., 2015[Aydın, A., Arslan, H., Şüküroğlu, M., Akkurt, M. & Büyükgüngör, O. (2015). Mol. Cryst. Liq. Cryst. 606, 216-236.]]. In addition, the C8—O1 bond length of 1.2500 (16) Å compares well with the value of 1.2343 (17) Å reported by Aydın et al. (2011[Aydın, A., Şüküroğlu, M., Akkurt, M. & Büyükgüngör, O. (2011). Acta Cryst. E67, o666-o667.]).

[Figure 1]
Figure 1
View of the title mol­ecule with displacement ellipsoids for non-H atoms drawn at the 30% probability level.

3. Supra­molecular features

In the crystal, N—H⋯O hydrogen bonds (Table 1[link], Fig. 2[link]) form dimers between centrosymmetric pairs of mol­ecules with [R_{2}^{2}](8) ring motifs. The dimers are connected by C—H⋯O and C—H⋯Cl hydrogen bonds, forming a three-dimensional network (Table 1[link], Fig. 3[link]). In addition, ππ stacking inter­actions [Cg2⋯Cg3i = 3.6665 (9) Å; Cg2 and Cg3 are the centroids of the 1,6-di­hydro­pyridazine ring (N1/N2/C7–C10) and the benzene ring (C1–C6); symmetry code: (i) 1 − x, −[{1\over 2}] + y, [{1\over 2}] − z)] contribute to the cohesion of the structure.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1⋯O1i 0.86 1.92 2.7705 (15) 170
C5—H5⋯O2ii 0.93 2.56 3.4737 (19) 166
C10—H10⋯O1iii 0.93 2.43 3.1614 (17) 136
C12—H12B⋯Cl1iv 0.97 2.79 3.754 (2) 173
Symmetry codes: (i) -x+1, -y, -z+1; (ii) x-1, y, z; (iii) [-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]; (iv) [x+1, -y+{\script{1\over 2}}, z+{\script{1\over 2}}].
[Figure 2]
Figure 2
View of a dimer, with [R_{2}^{2}](8) ring motif, formed by N—H⋯O hydrogen bonds (dashed lines) between two centrosymmetrically related mol­ecules.
[Figure 3]
Figure 3
Crystal packing and hydrogen bonding (dashed lines) in the title compound, viewed down the b axis. H atoms not involved in hydrogen bonding have been omitted.

4. Semi-empirical mol­ecular orbital calculations

Semi-empirical mol­ecular orbital calculations of the title compound were carried out using the AM1 method (Dewar et al., 1985[Dewar, M. J. S., Zoebisch, E. G., Healy, E. F. & Stewart, J. J. P. (1985). J. Am. Chem. Soc. 107, 3902-3909.]) with WinMopac7.2 software (Shchepin & Litvinov, 1998[Shchepin, R. & Litvinov, D. (1998). WinMopac7.21. Perm State University, Perm, Russia.]). A spatial view of the single mol­ecule of the title compound calculated in the gas phase is shown in Fig. 4[link]. The calculated dihedral angles between the pyridizine and benzene rings and between the pyridizine and morpholine (all atoms) ring sare 34.49 and 76.96°, respectively. The corresponding values obtained from the X-ray structure determination are 40.16 (7) and 12.97 (9)°, respectively. The morpholine ring of the title compound in the calculated gas phase seems to have a quite different orientation compared to that indicated by the X-ray structure determination. The calculated dipole moment is 2.13 Debye. The HOMO and LUMO energy levels are −9.05 and −1.01 eV, respectively.

[Figure 4]
Figure 4
Spatial view of the title compound calculated using the AM1 method.

5. Synthesis and crystallization

4-(4-Chloro­phen­yl)-6-(morpholin-4-yl)pyridazin-3(2H)-one was prepared by a reported literature protocol (Şüküroğlu et al., 2006[Şüküroğlu, M., Küpeli, E., Banoğlu, E., Ünlü, S., Yeşilada, E. & Şahin, M. F. (2006). Arzneim. Forsch. Drug Res. 56, 337-345.]). A solution of 3-chloro-4-phenyl-6-(morpholin-4-yl)-pyridazine (0.06 mol) and potassium acetate (0.08 mol) in 100 ml of acetic acid was refluxed for 10 h. The reaction mixture was then cooled and poured into ice–water. The precipitate was filtered off, washed with water and recrystallized from ethanol, giving yellow prismatic crystals. Yield 96%, m. p. 558 K. 1H NMR (CDCl3) δ 9.92 (s, 1H, NH), 7.76 (m, 2H, phenyl-H3, H5), 7.44 (m, 2H, phenyl-H2, H6), 7.23 (s, 1H, pyridazinone-H5), 3.85 (t, 4H, morpholine-H2, H6), 3.29 (t, 4H, morpholine-H3, H5) p.p.m. IR vmax cm−1 (KBr): 3124, 3053, 2960, 2861, 1656. Analysis C, H, N (C14H14ClN3O2)

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. H atoms were positioned geometrically and refined using a riding model with N—H = 0.86 Å, C—H = 0.93–0.97 Å, and with Uiso(H) = 1.2Ueq(C, N).

Table 2
Experimental details

Crystal data
Chemical formula C14H14ClN3O2
Mr 291.73
Crystal system, space group Monoclinic, P21/c
Temperature (K) 296
a, b, c (Å) 13.0977 (9), 7.4932 (4), 14.1123 (9)
β (°) 90.149 (5)
V3) 1385.03 (15)
Z 4
Radiation type Mo Kα
μ (mm−1) 0.28
Crystal size (mm) 0.80 × 0.38 × 0.08
 
Data collection
Diffractometer Stoe IPDS 2
Absorption correction Integration (X-RED32; Stoe & Cie, 2002[Stoe & Cie (2002). X-AREA and X-RED32. Stoe & Cie, Darmstadt, Germany.])
Tmin, Tmax 0.880, 0.978
No. of measured, independent and observed [I > 2σ(I)] reflections 8760, 2868, 2267
Rint 0.028
(sin θ/λ)max−1) 0.628
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.106, 1.04
No. of reflections 2868
No. of parameters 181
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.14, −0.23
Computer programs: X-AREA and X-RED32 (Stoe & Cie, 2002[Stoe & Cie (2002). X-AREA and X-RED32. Stoe & Cie, Darmstadt, Germany.]), SHELXS97 and SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), ORTEP-3 for Windows and WinGX (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]) and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Computing details top

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA (Stoe & Cie, 2002); data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009).

4-(4-Chlorophenyl)-6-(morpholin-4-yl)pyridazin-3(2H)-one top
Crystal data top
C14H14ClN3O2F(000) = 608
Mr = 291.73Dx = 1.399 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 11553 reflections
a = 13.0977 (9) Åθ = 1.6–28.0°
b = 7.4932 (4) ŵ = 0.28 mm1
c = 14.1123 (9) ÅT = 296 K
β = 90.149 (5)°Prism, yellow
V = 1385.03 (15) Å30.80 × 0.38 × 0.08 mm
Z = 4
Data collection top
Stoe IPDS 2
diffractometer
2868 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus2267 reflections with I > 2σ(I)
Plane graphite monochromatorRint = 0.028
Detector resolution: 6.67 pixels mm-1θmax = 26.5°, θmin = 1.6°
ω scansh = 1616
Absorption correction: integration
(XRED-32; Stoe & Cie, 2002)
k = 99
Tmin = 0.880, Tmax = 0.978l = 1717
8760 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.106H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0578P)2 + 0.1445P]
where P = (Fo2 + 2Fc2)/3
2868 reflections(Δ/σ)max < 0.001
181 parametersΔρmax = 0.14 e Å3
0 restraintsΔρmin = 0.23 e Å3
Special details top

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 e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F2 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 F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating -R-factor-obs etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cl10.16215 (4)0.21784 (11)0.00258 (4)0.0999 (2)
O10.42246 (7)0.04185 (14)0.40107 (6)0.0472 (3)
O20.99398 (9)0.3320 (2)0.22281 (11)0.0764 (5)
N10.58954 (8)0.10751 (17)0.41972 (8)0.0454 (4)
N20.68499 (9)0.16004 (17)0.39371 (8)0.0465 (4)
N30.78867 (9)0.28188 (18)0.27895 (9)0.0499 (4)
C10.42580 (10)0.17384 (18)0.20628 (9)0.0394 (4)
C20.43734 (11)0.1304 (2)0.11136 (10)0.0500 (5)
C30.35657 (13)0.1423 (2)0.04893 (11)0.0585 (5)
C40.26364 (12)0.1993 (2)0.08154 (11)0.0563 (5)
C50.24891 (11)0.2423 (2)0.17507 (12)0.0534 (5)
C60.33006 (10)0.2283 (2)0.23759 (10)0.0455 (4)
C70.51501 (10)0.16802 (18)0.27082 (9)0.0382 (4)
C80.50364 (10)0.10152 (19)0.36713 (9)0.0393 (4)
C90.69357 (10)0.21801 (19)0.30668 (10)0.0423 (4)
C100.60866 (10)0.22402 (19)0.24347 (10)0.0427 (4)
C110.87216 (12)0.2561 (3)0.34556 (13)0.0625 (6)
C120.96240 (13)0.3681 (3)0.31683 (15)0.0724 (7)
C130.91285 (13)0.3718 (4)0.16077 (15)0.0835 (8)
C140.81944 (13)0.2585 (3)0.18073 (14)0.0745 (7)
H10.583300.073500.477600.0550*
H20.500700.092600.089500.0600*
H30.365000.112100.014500.0700*
H50.185300.280400.196100.0640*
H60.320500.255500.301200.0550*
H100.617700.267200.182300.0510*
H11A0.891600.131200.346800.0750*
H11B0.850300.289700.408700.0750*
H12A0.944500.493300.322200.0870*
H12B1.018700.345000.359900.0870*
H13A0.934700.351900.096000.1000*
H13B0.895000.496900.167100.1000*
H14A0.764100.293500.138900.0890*
H14B0.834900.133900.168900.0890*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0672 (3)0.1570 (6)0.0753 (3)0.0021 (3)0.0358 (2)0.0166 (3)
O10.0438 (5)0.0619 (6)0.0358 (5)0.0068 (5)0.0003 (4)0.0016 (4)
O20.0386 (5)0.0910 (10)0.0996 (10)0.0011 (6)0.0060 (6)0.0097 (8)
N10.0441 (6)0.0552 (7)0.0370 (6)0.0050 (5)0.0037 (4)0.0043 (5)
N20.0401 (6)0.0511 (7)0.0482 (6)0.0027 (5)0.0062 (5)0.0051 (5)
N30.0353 (6)0.0576 (8)0.0569 (7)0.0008 (5)0.0028 (5)0.0103 (6)
C10.0399 (7)0.0394 (7)0.0390 (6)0.0022 (5)0.0027 (5)0.0050 (5)
C20.0474 (8)0.0604 (9)0.0422 (7)0.0042 (7)0.0001 (6)0.0033 (6)
C30.0631 (9)0.0735 (11)0.0389 (7)0.0033 (8)0.0075 (6)0.0036 (7)
C40.0480 (8)0.0671 (11)0.0537 (8)0.0070 (7)0.0159 (6)0.0131 (7)
C50.0378 (7)0.0626 (10)0.0598 (9)0.0002 (6)0.0038 (6)0.0085 (7)
C60.0405 (7)0.0524 (8)0.0437 (7)0.0010 (6)0.0017 (5)0.0017 (6)
C70.0389 (6)0.0372 (7)0.0386 (7)0.0030 (5)0.0018 (5)0.0009 (5)
C80.0411 (6)0.0404 (7)0.0365 (6)0.0006 (5)0.0019 (5)0.0023 (5)
C90.0371 (6)0.0403 (7)0.0496 (7)0.0024 (5)0.0029 (5)0.0037 (6)
C100.0399 (7)0.0441 (8)0.0440 (7)0.0039 (6)0.0010 (5)0.0079 (6)
C110.0414 (8)0.0720 (11)0.0740 (11)0.0014 (7)0.0124 (7)0.0149 (9)
C120.0418 (8)0.0806 (13)0.0947 (14)0.0067 (8)0.0117 (8)0.0124 (11)
C130.0474 (9)0.1222 (19)0.0809 (13)0.0066 (10)0.0089 (8)0.0210 (13)
C140.0456 (9)0.1111 (16)0.0669 (11)0.0097 (9)0.0074 (8)0.0022 (11)
Geometric parameters (Å, º) top
Cl1—C41.7379 (17)C7—C81.4556 (18)
O1—C81.2500 (16)C7—C101.3535 (19)
O2—C121.417 (3)C9—C101.4246 (19)
O2—C131.407 (2)C11—C121.506 (3)
N1—N21.3620 (16)C13—C141.516 (3)
N1—C81.3470 (17)C2—H20.9300
N2—C91.3079 (18)C3—H30.9300
N3—C91.3915 (18)C5—H50.9300
N3—C111.453 (2)C6—H60.9300
N3—C141.455 (2)C10—H100.9300
N1—H10.8600C11—H11A0.9700
C1—C21.3872 (19)C11—H11B0.9700
C1—C61.3918 (19)C12—H12A0.9700
C1—C71.4803 (18)C12—H12B0.9700
C2—C31.378 (2)C13—H13A0.9700
C3—C41.371 (2)C13—H13B0.9700
C4—C51.373 (2)C14—H14A0.9700
C5—C61.384 (2)C14—H14B0.9700
C12—O2—C13108.69 (14)N3—C14—C13109.58 (16)
N2—N1—C8128.84 (11)C1—C2—H2119.00
N1—N2—C9115.48 (11)C3—C2—H2119.00
C9—N3—C11116.43 (13)C2—C3—H3120.00
C9—N3—C14118.48 (13)C4—C3—H3120.00
C11—N3—C14112.98 (13)C4—C5—H5120.00
C8—N1—H1116.00C6—C5—H5120.00
N2—N1—H1116.00C1—C6—H6120.00
C2—C1—C7119.96 (12)C5—C6—H6120.00
C2—C1—C6118.42 (12)C7—C10—H10119.00
C6—C1—C7121.58 (12)C9—C10—H10119.00
C1—C2—C3121.12 (14)N3—C11—H11A110.00
C2—C3—C4119.11 (14)N3—C11—H11B110.00
Cl1—C4—C3119.21 (12)C12—C11—H11A110.00
Cl1—C4—C5119.25 (12)C12—C11—H11B110.00
C3—C4—C5121.54 (15)H11A—C11—H11B108.00
C4—C5—C6119.06 (14)O2—C12—H12A109.00
C1—C6—C5120.73 (13)O2—C12—H12B109.00
C8—C7—C10117.86 (12)C11—C12—H12A109.00
C1—C7—C10122.00 (12)C11—C12—H12B109.00
C1—C7—C8120.14 (11)H12A—C12—H12B108.00
O1—C8—N1120.72 (12)O2—C13—H13A109.00
O1—C8—C7124.71 (12)O2—C13—H13B109.00
N1—C8—C7114.57 (12)C14—C13—H13A109.00
N2—C9—N3117.23 (12)C14—C13—H13B109.00
N3—C9—C10120.73 (13)H13A—C13—H13B108.00
N2—C9—C10121.98 (12)N3—C14—H14A110.00
C7—C10—C9121.21 (13)N3—C14—H14B110.00
N3—C11—C12109.97 (16)C13—C14—H14A110.00
O2—C12—C11112.14 (16)C13—C14—H14B110.00
O2—C13—C14111.97 (19)H14A—C14—H14B108.00
C13—O2—C12—C1160.9 (2)C7—C1—C6—C5176.41 (13)
C12—O2—C13—C1461.1 (2)C2—C1—C7—C1039.3 (2)
C8—N1—N2—C92.5 (2)C6—C1—C7—C10138.37 (15)
N2—N1—C8—C72.9 (2)C1—C2—C3—C40.5 (2)
N2—N1—C8—O1176.78 (13)C2—C3—C4—Cl1178.98 (12)
N1—N2—C9—C100.5 (2)C2—C3—C4—C50.9 (2)
N1—N2—C9—N3176.65 (12)C3—C4—C5—C60.3 (2)
C11—N3—C9—C10175.00 (15)Cl1—C4—C5—C6179.64 (12)
C14—N3—C11—C1251.2 (2)C4—C5—C6—C10.9 (2)
C9—N3—C11—C12166.70 (15)C1—C7—C8—O12.1 (2)
C11—N3—C9—N27.8 (2)C10—C7—C8—O1178.24 (14)
C14—N3—C9—N2147.76 (15)C10—C7—C8—N11.46 (19)
C11—N3—C14—C1351.3 (2)C8—C7—C10—C90.1 (2)
C14—N3—C9—C1035.0 (2)C1—C7—C10—C9179.78 (13)
C9—N3—C14—C13167.46 (16)C1—C7—C8—N1178.23 (12)
C2—C1—C7—C8141.00 (14)N3—C9—C10—C7177.67 (13)
C7—C1—C2—C3177.11 (13)N2—C9—C10—C70.6 (2)
C6—C1—C2—C30.7 (2)N3—C11—C12—O255.9 (2)
C6—C1—C7—C841.30 (19)O2—C13—C14—N356.5 (2)
C2—C1—C6—C51.3 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.861.922.7705 (15)170
C5—H5···O2ii0.932.563.4737 (19)166
C6—H6···O10.932.512.9538 (17)109
C10—H10···O1iii0.932.433.1614 (17)136
C12—H12B···Cl1iv0.972.793.754 (2)173
Symmetry codes: (i) x+1, y, z+1; (ii) x1, y, z; (iii) x+1, y+1/2, z+1/2; (iv) x+1, y+1/2, z+1/2.
 

Acknowledgements

The authors acknowledge the Faculty of Arts and Sciences, Ondokuz Mayıs University, Turkey, for the use of the Stoe IPDS 2 diffractometer (purchased under grant F.279 of the University Research Fund).

References

First citationAydın, A., Arslan, H., Şüküroğlu, M., Akkurt, M. & Büyükgüngör, O. (2015). Mol. Cryst. Liq. Cryst. 606, 216–236.  Google Scholar
First citationAydın, A., Şüküroğlu, M., Akkurt, M. & Büyükgüngör, O. (2011). Acta Cryst. E67, o666–o667.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationBrogden, R. N. (1986). Drugs, 32, 60–70.  CrossRef PubMed Web of Science Google Scholar
First citationDewar, M. J. S., Zoebisch, E. G., Healy, E. F. & Stewart, J. J. P. (1985). J. Am. Chem. Soc. 107, 3902–3909.  CrossRef CAS Web of Science Google Scholar
First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationShchepin, R. & Litvinov, D. (1998). WinMopac7.21. Perm State University, Perm, Russia.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationStoe & Cie (2002). X-AREA and X-RED32. Stoe & Cie, Darmstadt, Germany.  Google Scholar
First citationŞüküroğlu, M., Küpeli, E., Banoğlu, E., Ünlü, S., Yeşilada, E. & Şahin, M. F. (2006). Arzneim. Forsch. Drug Res. 56, 337–345.  Google Scholar

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