N-(4-Acetyl­phen­yl)-N′-(4-fluoro­phen­yl)urea

Çelik, Í.; Atioğlu, Z.; Ordu, G.; Gezegen, H.; Akkurt, M.

doi:10.1107/S2414314618005540

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 3| Part 4| April 2018| x180554

https://doi.org/10.1107/S2414314618005540

Open

access

N-(4-Acetylphenyl)-N′-(4-fluorophenyl)urea

Ísmail Çelik,^a Zeliha Atioğlu,^b Gamze Ordu,^c Hayrettin Gezegen ^d and Mehmet Akkurt ^e ^*

^aDepartment of Physics, Faculty of Sciences, Cumhuriyet University, 58140 Sivas, Turkey, ^bİlke Education and Health Foundation, Cappadocia University, Cappadocia Vocational College, The Medical Imaging Techniques Program, 50420 Mustafapaşa, Ürgüp, Nevşehir, Turkey, ^cCumhuriyet University, Institute of Science, Department of Physics, 58140 Sivas, Turkey, ^dDepartment of Nutrition and Dietetics, Faculty of Health Sciences, Cumhuriyet University, 58140 Sivas, Turkey, and ^eDepartment of Physics, Faculty of Sciences, Erciyes University, 38039 Kayseri, Turkey
^*Correspondence e-mail: akkurt@erciyes.edu.tr

Edited by C. Rizzoli, Universita degli Studi di Parma, Italy (Received 2 April 2018; accepted 9 April 2018; online 12 April 2018)

In the title compound, C₁₅H₁₃FN₂O₂, the fluorophenyl and 4-acetylphenyl rings are twisted from each other by a dihedral angle of 11.6 (2)°. In the crystal, molecules are packed into layers parallel to (010). Each layer contains the molecules linked by a pair of strong N—H⋯O hydrogen bonds, with an R₂²(14) ring motif, while strong C—H⋯F hydrogen bonds forming R₄²(26) ring motifs connect molecules into a two-dimensional network. The intermolecular interactions have been investigated using Hirshfeld surface studies and two-dimensional fingerprint plots.

Keywords: crystal structure; urea moiety; N—H⋯O hydrogen bonds; Hirshfeld surface analysis.

CCDC reference: 1835898

Structure description

Acetophenones having different substituents in synthetic organic chemistry are used as an important building block (Bing-Wei, 2010 ). In particular, they are frequently used in conjunction with aldehydes in the synthesis of chalcone derivatives (Kocyigit et al., 2018 ; Karaman et al., 2010 ; Ceylan et al., 2011 ), which are used as starting materials in the preparation of useful and multifunctional heterocyclic and bioactive compounds (Gürdere, Gümüş et al., 2017 ; Gürdere, Kamo et al., 2017 ; Gezegen et al., 2013 ). In this article we report the crystal structure of 4-fluorophenylurea-substituted acetophenone, namely N-(4-acetylphenyl)-N′-(4-fluorophenyl)urea.

In the title molecule (Fig. 1), the fluorophenyl ring (C1–C6) and the 4-acetylphenyl ring (C8–C13) are twisted from each other, making a dihedral angle of 11.6 (2)°. The mean plane of the four essentially planar atoms of the urea moiety (C7/N1/N2/O1; r.m.s deviation = 0.004 Å) forms dihedral angles of 35.9 (3) and 29.2 (2)°, respectively, with the mean planes of the fluorophenyl and 4-acetylphenyl rings. The molecular conformation is stabilized by two weak intramolecular C—H⋯O interactions (Table 1). In the crystal (Figs. 2 and 3), N—H⋯O and C—H⋯F hydrogen bonds (Table 1) link the adjacent molecules into layers parallel to (010) forming R₂²(14) and R₄²(26) ring motifs. C—H⋯π and π–π interactions are not observed.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N⋯O1ⁱ	0.79 (6)	2.17 (6)	2.927 (5)	160 (5)
N2—H2N⋯O2ⁱⁱ	0.88 (6)	2.30 (6)	3.070 (6)	147 (5)
C1—H1⋯O1	0.93	2.52	2.932 (6)	107
C10—H10⋯F1ⁱⁱⁱ	0.93	2.49	3.386 (6)	162
C13—H13⋯O1	0.93	2.33	2.887 (7)	118
Symmetry codes: (i) x-1, y, z; (ii) x-1, y+1, z; (iii) $[x-{\script{1\over 2}}, -y+1, z+{\script{1\over 2}}]$ .

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

Figure 2
A view along the a axis of the crystal packing of the title compound. H atoms not involved in hydrogen bonding (dotted lines) are omitted for clarity.

Figure 3
A view along the b axis of the crystal packing of the title compound. H atoms not involved in hydrogen bonding (dashed lines) are omitted for clarity.

The values of the geometric parameters of the title structure are comparable to those in the related structures N,N′-bis(pentafluorophenyl)urea (Jai-nhuknan et al., 1997 ), N,N′-bis(4-fluorophenyl)urea (Loh et al., 2010 ) and polymorphs of 1,3-bis(3-fluorophenyl) urea (Capacci-Daniel et al., 2016 ) and 1-(3-fluorophenyl)-3-(4-nitrophenyl)urea (Lin et al., 2012 ).

The three-dimensional d_norm surface is a useful tool to analyse and visualize the inter-molecular interactions. d_norm takes negative or positive values depending on whether the intermolecular contact is shorter or longer than the van der Waals radii (Spackman & Jayatilaka, 2009 ). It is evident from the bright-red spots appearing near the oxygen atom on the Hirshfeld surface mapped over d_norm in Fig. 4 that these atoms play a significant role in the molecular packing. The donors and acceptors of N—H⋯O and C—H⋯F interactions are also represented with blue (positive potential) and red regions (negative potential), respectively, on the Hirshfeld surface mapped over the d_norm in Fig. 5. The red points, which represent closer contacts and negative d_norm values on the surface, correspond to the N—H⋯O, C—H⋯F and C—H⋯O interactions. The percentage contributions of various contacts to the total Hirshfeld surface are as follows: H⋯H (36.5%), F⋯H/H⋯F (13.3%), O⋯H/H⋯O (15.4%), C⋯H/H⋯C (24.7%), N⋯H/H⋯N (2.3%), C⋯C (3.1%), O⋯C/C⋯O (1.7%), C⋯N/N⋯C (1.5%) and F⋯C/C⋯F (0.7%), as shown in the two-dimensional fingerprint plots in Fig. 5. The three-dimensional shape-index surface of the title compound is shown in Fig. 6.

Figure 4
View of the three-dimensional Hirshfeld surface of the title compound mapped with d_norm.

Figure 5
Two-dimensional fingerprint plots of the title compound, showing (a) all interactions, and delineated into (b) H⋯H, (c) C⋯H, (d) O⋯H, (e) F⋯H, (f) C⋯C, (g) N⋯H, (h) C⋯O and (i) C⋯N interactions [d_e and d_i represent the distances from a point on the Hirshfeld surface to the nearest atoms outside (external) and inside (internal) the surface, respectively].

Figure 6
Hirshfeld surface of the title complex plotted over shape-index.

Synthesis and crystallization

For the synthesis of 1-(4-acetylphenyl)-3-(4-fluorophenyl)urea, see Gezegen et al. (2017 ).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. Seventeen reflections (3 1 23), ( $[\overline{1}]$ 5 3), (0 8 0), (3 3 $[\overline{10}]$ ), (4 0 20), (1 5 $[\overline{3}]$ ), ( $[\overline{1}]$ 4 $[\overline{13}]$ ), (1 4 13), ( $[\overline{4}]$ 4 11), (2 5 $[\overline{11}]$ ), (0 6 7), (6 3 $[\overline{1}]$ ), ( $[\overline{3}]$ 3 10), ( $[\overline{2}]$ 6 $[\overline{17}]$ ), (0 6 $[\overline{7}]$ ), (5 1 $[\overline{16}]$ ) and (0 1 14) were omitted from the refinement because of large differences between observed and calculated intensities.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₅H₁₃FN₂O₂
M_r	272.27
Crystal system, space group	Monoclinic, Pn
Temperature (K)	296
a, b, c (Å)	4.8061 (15), 6.617 (2), 20.364 (7)
β (°)	91.417 (10)
V (Å³)	647.4 (4)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.10
Crystal size (mm)	0.15 × 0.12 × 0.11

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Sheldrick, 2003 )
T_min, T_max	0.547, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	15964, 2991, 2573
R_int	0.053
(sin θ/λ)_max (Å⁻¹)	0.666

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.062, 0.134, 1.11
No. of reflections	2991
No. of parameters	191
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.18, −0.20
Computer programs: APEX2 and SAINT (Bruker, 2007 ), SHELXS97 (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), ORTEP-3 for Windows (Farrugia, 2012 ) and PLATON (Spek, 2009 ).

Structural data

CCDC reference: 1835898

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S2414314618005540/rz4022sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314618005540/rz4022Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314618005540/rz4022Isup3.cml

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: PLATON (Spek, 2009).

N-(4-Acetylphenyl)-N'-(4-fluorophenyl)urea top

Crystal data top

C₁₅H₁₃FN₂O₂	F(000) = 284
M_r = 272.27	D_x = 1.397 Mg m⁻³
Monoclinic, Pn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P -2yac	Cell parameters from 9977 reflections
a = 4.8061 (15) Å	θ = 3.0–28.3°
b = 6.617 (2) Å	µ = 0.10 mm⁻¹
c = 20.364 (7) Å	T = 296 K
β = 91.417 (10)°	Block, bronze
V = 647.4 (4) Å³	0.15 × 0.12 × 0.11 mm
Z = 2

Data collection top

Bruker APEXII CCD diffractometer	2573 reflections with I > 2σ(I)
φ and ω scans	R_int = 0.053
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	θ_max = 28.3°, θ_min = 3.1°
T_min = 0.547, T_max = 0.746	h = −6→6
15964 measured reflections	k = −8→8
2991 independent reflections	l = −27→27

Refinement top

Refinement on F²	2 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.062	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.134	W = 1/[Σ²(FO²) + 0.564P] WHERE P = (FO² + 2FC²)/3
S = 1.11	(Δ/σ)_max < 0.001
2991 reflections	Δρ_max = 0.18 e Å⁻³
191 parameters	Δρ_min = −0.20 e Å⁻³

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 esds 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 > 2sigma(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.

H atoms of NH groups were located in difference Fourier maps [N1—H1N = 0.79 (6) and N2—H2N = 0.88 (6) Å] and refined freely. All H atoms attached to carbon were placed in geometrically idealized positions and constrained to ride on their parent atoms with C—H distances of 0.93 - 0.96 Å and U_iso(H) = 1.2 or 1.5U_eq(C).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1	0.4143 (11)	0.6742 (8)	0.0165 (2)	0.0579 (13)
H1	0.5055	0.5510	0.0124	0.069*
C2	0.4738 (12)	0.8333 (10)	−0.0252 (3)	0.0686 (16)
H2	0.6100	0.8186	−0.0565	0.082*
C3	0.3346 (13)	1.0090 (8)	−0.0204 (3)	0.0620 (14)
C4	0.1366 (12)	1.0392 (9)	0.0249 (3)	0.0667 (15)
H4	0.0419	1.1615	0.0272	0.080*
C5	0.0800 (12)	0.8832 (8)	0.0676 (3)	0.0627 (14)
H5	−0.0538	0.9017	0.0992	0.075*
C6	0.2168 (8)	0.7011 (7)	0.0643 (2)	0.0430 (10)
C7	0.3297 (8)	0.4208 (7)	0.1394 (2)	0.0448 (10)
C8	0.3199 (8)	0.1346 (6)	0.2184 (2)	0.0390 (9)
C9	0.2016 (9)	0.0633 (7)	0.2753 (2)	0.0497 (11)
H9	0.0585	0.1364	0.2940	0.060*
C10	0.2898 (10)	−0.1112 (7)	0.3044 (2)	0.0519 (12)
H10	0.2057	−0.1544	0.3426	0.062*
C11	0.5022 (9)	−0.2266 (6)	0.2785 (2)	0.0395 (9)
C12	0.6243 (10)	−0.1525 (7)	0.2220 (2)	0.0512 (12)
H12	0.7700	−0.2244	0.2040	0.061*
C13	0.5364 (10)	0.0236 (8)	0.1921 (3)	0.0547 (12)
H13	0.6217	0.0684	0.1543	0.066*
C14	0.6020 (9)	−0.4180 (7)	0.3072 (2)	0.0483 (11)
C15	0.4600 (13)	−0.5012 (9)	0.3662 (3)	0.0676 (15)
H15A	0.4963	−0.4147	0.4032	0.101*
H15B	0.5298	−0.6343	0.3756	0.101*
H15C	0.2630	−0.5079	0.3574	0.101*
F1	0.3976 (9)	1.1663 (6)	−0.06090 (19)	0.1009 (14)
N1	0.1477 (8)	0.5458 (6)	0.1088 (2)	0.0486 (10)
N2	0.2112 (7)	0.3066 (6)	0.1886 (2)	0.0467 (9)
O1	0.5754 (6)	0.4085 (5)	0.12620 (19)	0.0573 (9)
O2	0.7956 (8)	−0.5106 (6)	0.2841 (2)	0.0702 (11)
H1N	−0.016 (12)	0.538 (8)	0.112 (3)	0.054 (15)*
H2N	0.057 (12)	0.366 (9)	0.200 (3)	0.074 (18)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
F1	0.130 (3)	0.089 (3)	0.086 (3)	0.004 (3)	0.044 (2)	0.039 (2)
O1	0.0299 (14)	0.058 (2)	0.085 (2)	−0.0003 (15)	0.0178 (15)	0.0140 (18)
O2	0.065 (2)	0.052 (2)	0.094 (3)	0.0236 (18)	0.015 (2)	0.006 (2)
N1	0.0310 (18)	0.048 (2)	0.068 (3)	−0.0002 (17)	0.0132 (17)	0.0142 (19)
N2	0.0319 (18)	0.041 (2)	0.068 (2)	0.0071 (15)	0.0196 (17)	0.0078 (18)
C1	0.064 (3)	0.053 (3)	0.058 (3)	0.008 (2)	0.022 (2)	−0.002 (2)
C2	0.076 (4)	0.073 (4)	0.059 (3)	0.009 (3)	0.031 (3)	0.008 (3)
C3	0.075 (3)	0.056 (3)	0.057 (3)	−0.004 (3)	0.021 (3)	0.014 (3)
C4	0.084 (4)	0.053 (3)	0.063 (3)	0.014 (3)	0.025 (3)	0.013 (3)
C5	0.067 (3)	0.057 (3)	0.066 (3)	0.015 (3)	0.032 (3)	0.016 (3)
C6	0.036 (2)	0.043 (2)	0.050 (2)	−0.0046 (18)	0.0094 (18)	0.0023 (19)
C7	0.032 (2)	0.039 (2)	0.064 (3)	0.0008 (18)	0.0083 (19)	0.001 (2)
C8	0.0322 (18)	0.034 (2)	0.052 (2)	0.0072 (17)	0.0109 (16)	−0.0025 (18)
C9	0.048 (2)	0.044 (2)	0.058 (3)	0.014 (2)	0.018 (2)	0.004 (2)
C10	0.053 (3)	0.049 (3)	0.055 (3)	0.012 (2)	0.022 (2)	0.003 (2)
C11	0.0349 (19)	0.036 (2)	0.047 (2)	0.0022 (17)	0.0024 (17)	−0.0004 (17)
C12	0.044 (2)	0.047 (3)	0.063 (3)	0.019 (2)	0.020 (2)	0.000 (2)
C13	0.052 (3)	0.053 (3)	0.060 (3)	0.014 (2)	0.021 (2)	0.009 (2)
C14	0.044 (2)	0.040 (2)	0.060 (3)	0.007 (2)	−0.004 (2)	−0.004 (2)
C15	0.074 (4)	0.055 (3)	0.074 (4)	0.010 (3)	0.003 (3)	0.015 (3)

Geometric parameters (Å, º) top

F1—C3	1.367 (7)	C9—C10	1.361 (6)
O1—C7	1.220 (5)	C10—C11	1.389 (6)
O2—C14	1.218 (6)	C11—C12	1.394 (6)
N1—C6	1.415 (6)	C11—C14	1.470 (6)
N1—C7	1.346 (6)	C12—C13	1.376 (7)
N2—C7	1.388 (6)	C14—C15	1.501 (7)
N2—C8	1.386 (6)	C1—H1	0.9300
C1—C2	1.387 (8)	C2—H2	0.9300
C1—C6	1.388 (6)	C4—H4	0.9300
N1—H1N	0.79 (6)	C5—H5	0.9300
C2—C3	1.346 (8)	C9—H9	0.9300
N2—H2N	0.88 (6)	C10—H10	0.9300
C3—C4	1.356 (9)	C12—H12	0.9300
C4—C5	1.381 (8)	C13—H13	0.9300
C5—C6	1.375 (7)	C15—H15A	0.9600
C8—C9	1.386 (6)	C15—H15B	0.9600
C8—C13	1.392 (6)	C15—H15C	0.9600

C6—N1—C7	125.7 (4)	C11—C12—C13	122.2 (4)
C7—N2—C8	127.3 (4)	C8—C13—C12	120.1 (5)
C2—C1—C6	119.2 (5)	O2—C14—C15	119.4 (4)
C6—N1—H1N	110 (4)	C11—C14—C15	118.9 (4)
C7—N1—H1N	124 (4)	O2—C14—C11	121.6 (4)
C7—N2—H2N	108 (4)	C2—C1—H1	120.00
C1—C2—C3	120.1 (5)	C6—C1—H1	120.00
C8—N2—H2N	124 (4)	C1—C2—H2	120.00
F1—C3—C2	119.7 (5)	C3—C2—H2	120.00
F1—C3—C4	117.9 (5)	C3—C4—H4	121.00
C2—C3—C4	122.3 (6)	C5—C4—H4	121.00
C3—C4—C5	118.1 (5)	C4—C5—H5	119.00
C4—C5—C6	121.5 (5)	C6—C5—H5	119.00
N1—C6—C5	119.0 (4)	C8—C9—H9	119.00
C1—C6—C5	118.9 (5)	C10—C9—H9	119.00
N1—C6—C1	122.1 (4)	C9—C10—H10	119.00
O1—C7—N1	124.1 (4)	C11—C10—H10	119.00
O1—C7—N2	122.6 (4)	C11—C12—H12	119.00
N1—C7—N2	113.3 (3)	C13—C12—H12	119.00
C9—C8—C13	117.9 (4)	C8—C13—H13	120.00
N2—C8—C9	119.2 (4)	C12—C13—H13	120.00
N2—C8—C13	122.8 (4)	C14—C15—H15A	109.00
C8—C9—C10	121.5 (4)	C14—C15—H15B	109.00
C9—C10—C11	121.7 (4)	C14—C15—H15C	109.00
C10—C11—C12	116.6 (4)	H15A—C15—H15B	110.00
C10—C11—C14	123.9 (4)	H15A—C15—H15C	109.00
C12—C11—C14	119.4 (4)	H15B—C15—H15C	109.00

C7—N1—C6—C1	42.0 (7)	C4—C5—C6—N1	−179.2 (5)
C7—N1—C6—C5	−139.4 (5)	C4—C5—C6—C1	−0.5 (8)
C6—N1—C7—O1	−9.9 (7)	N2—C8—C9—C10	176.2 (4)
C6—N1—C7—N2	169.5 (4)	C13—C8—C9—C10	−1.0 (7)
C7—N2—C8—C9	167.2 (4)	N2—C8—C13—C12	−176.2 (4)
C7—N2—C8—C13	−15.8 (7)	C9—C8—C13—C12	0.9 (7)
C8—N2—C7—N1	163.8 (4)	C8—C9—C10—C11	−0.1 (7)
C8—N2—C7—O1	−16.8 (7)	C9—C10—C11—C12	1.3 (7)
C6—C1—C2—C3	−2.1 (8)	C9—C10—C11—C14	−178.8 (4)
C2—C1—C6—N1	−179.5 (5)	C10—C11—C12—C13	−1.4 (7)
C2—C1—C6—C5	1.9 (7)	C14—C11—C12—C13	178.7 (4)
C1—C2—C3—C4	0.8 (9)	C10—C11—C14—O2	−177.4 (4)
C1—C2—C3—F1	178.9 (5)	C10—C11—C14—C15	3.0 (7)
F1—C3—C4—C5	−177.5 (5)	C12—C11—C14—O2	2.5 (7)
C2—C3—C4—C5	0.6 (9)	C12—C11—C14—C15	−177.2 (4)
C3—C4—C5—C6	−0.7 (9)	C11—C12—C13—C8	0.4 (8)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O1ⁱ	0.79 (6)	2.17 (6)	2.927 (5)	160 (5)
N2—H2N···O2ⁱⁱ	0.88 (6)	2.30 (6)	3.070 (6)	147 (5)
C1—H1···O1	0.93	2.52	2.932 (6)	107
C10—H10···F1ⁱⁱⁱ	0.93	2.49	3.386 (6)	162
C13—H13···O1	0.93	2.33	2.887 (7)	118

Symmetry codes: (i) x−1, y, z; (ii) x−1, y+1, z; (iii) x−1/2, −y+1, z+1/2.

Funding information

The authors are indebted to the Technical Research Council of Turkey (Grant TUBİTAK-114Z634) for financial support of this work.

References

Bing-Wei, X. (2010). Synth. Commun. 38, 2826–2837. Google Scholar
Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Capacci-Daniel, C. A., Bertke, J. A., Dehghan, S., Hiremath-Darji, R. & Swift, J. A. (2016). Acta Cryst. C72, 692–696. Web of Science CSD CrossRef IUCr Journals Google Scholar
Ceylan, M., Gürdere, M. B., Karaman, İ. & Gezegen, H. (2011). Med. Chem. Res. 20, 109–115. Web of Science CrossRef CAS Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Gezegen, H., Ceylan, M., Karaman, İ. & Şahin, E. (2013). Synth. Commun. 44, 1084–1093. Web of Science CSD CrossRef Google Scholar
Gezegen, H., Hepokur, C., Tutar, U. & Ceylan, M. (2017). Chem. Biodivers. 14, e1700223. doi: 10.1002/cbdv. 201700223. Web of Science CrossRef Google Scholar
Gürdere, M. B., Gümüş, O., Yaglioglu, A. S., Budak, Y. & Ceylan, M. (2017). Res. Chem. Intermed. 43, 1277–1289. Google Scholar
Gürdere, M. B., Kamo, E., Yağlıoğlu, A. Ş., Budak, Y. & Ceylan, M. (2017). Turk. J. Chem. 41, 263–271. Google Scholar
Jai-nhuknan, J., Karipides, A. G., Hughes, J. M. & Cantrell, J. S. (1997). Acta Cryst. C53, 455–457. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Karaman, İ., Gezegen, H., Gürdere, M. B., Dingil, A. & Ceylan, M. (2010). Chem. Biodivers. 7, 400–408. Web of Science CrossRef CAS Google Scholar
Kocyigit, U. M., Budak, Y., Gürdere, M. B., Ertürk, F., Yencilek, B., Taslimi, P., Gülçin, İ. & Ceylan, M. (2018). Arch. Physiol. Biochem. 124, 61–68. Web of Science CrossRef CAS Google Scholar
Lin, M.-S., Shi, Y., Zhang, S.-Y. & Li, Y.-L. (2012). Acta Cryst. E68, o2030. CSD CrossRef IUCr Journals Google Scholar
Loh, W.-S., Fun, H.-K., Sarveswari, S., Vijayakumar, V. & Ragavan, R. V. (2010). Acta Cryst. E66, o1319. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2003). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). 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

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.