Synthesis and crystal structure of 2-(1,3-dithietan-2-yl­idene)cyclo­hexane-1,3-dione

Kellou, S.; Brihi, O.; Chetioui, S.; Salah Eddine, L.; Abdelali, F.; Boudjada, A.

doi:10.1107/S2056989022009872

research communications

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 78| Part 11| November 2022| Pages 1118-1121

https://doi.org/10.1107/S2056989022009872

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Synthesis and crystal structure of 2-(1,3-dithietan-2-ylidene)cyclohexane-1,3-dione

Sabah Kellou,^a Ouarda Brihi,^a Souheyla Chetioui,^b,^c ^* Lemallem Salah Eddine,^b Fiala Abdelali ^b and Ali Boudjada ^a

^aLaboratoire de Cristallographie, Département de Physique, Université des Frères Mentouri de Constantine-1, 25000 Constantine, Algeria, ^bUnité de Recherche de Chimie de l'Environnement et Moléculaire Structurale (URCHEMS), Département de Chimie, Université des Frères Mentouri de Constantine-1, 25000 Constantine, Algeria, and ^cFaculté de Technologie, Université Mohamed Boudiaf, M'sila, Algeria
^*Correspondence e-mail: souheila_chetioui@umc.edu.dz

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 4 July 2022; accepted 9 October 2022; online 13 October 2022)

The title compound, C₈H₈O₂S₂, contains a cyclohexane-1,3-dione ring, which has a twist-boat conformation. The C₂S₂ ring is close to planar (r.m.s. deviation = 0.023 Å) and the dihedral angle between the mean planes of the cyclohexane and 1,3-dithietane rings is 9.1 (3)°. Short intramolecular S⋯O contacts occur [2.719 (5) and 2.740 (5) Å]. In the crystal, the molecules are linked by weak C—H⋯S hydrogen bonds and short [3.165 (5) Å] S⋯O contacts, forming (010) layers. The prevalence of these interactions is illustrated by an analysis of the three-dimensional Hirshfeld surface and by two-dimensional fingerprint plots.

Keywords: ketene dithioacetal; hydrogen bond; Hirshfeld surface analysis; crystal structure.

CCDC reference: 2211891

1. Chemical context

Ketene dithioacetals are useful intermediates in organic synthesis and have been used for the preparation of heterocyclic compounds (Kolb, 1990 ; Ila et al., 2001 ). The synthesis of trifluoromethyl ketene dithioacetals has applications in the field of pharmaceuticals and agrochemicals (Gouault-Bironneau et al., 2012 ; Timoshenko & Portella, 2009 ). The functionalization of ketene dithioacetals provides more powerful tools for the development of new intermediates (Wang et al., 2011 ; Gao et al., 2010 ; Hu et al., 2012 ). The direct formation of a C—C bond has been carried out by reacting a cyano ketene dithioacetal and Morita–Baylis–Hillman (MBH) alcohols resulting from the reaction of acrylonitrile and aryl aldehydes. This reaction led to the corresponding 1,4-pentadiene derivatives (Zhao et al., 2007 ). Fiala et al. (2007 ) have studied the inhibitive action of some synthetic ketene dithioacetal derivatives towards the corrosion of copper in aerated nitric acid solutions. They concluded that these compounds are good inhibitors of copper corrosion in this medium. In the present study, we report the synthesis, crystal structure and Hirshfeld surface analysis of the new title 1,3-dithian-2-ylidene derivative, C₈H₈O₂S₂, (I).

2. Structural commentary

In the molecular structure of (I), the cyclohexane and dithietane rings are linked by a C=C bond of 1.364 (8) Å (Fig. 1). The cyclohexane-1,3-dione ring adopts a twist-boat conformation, as seen in related compounds (Kuppan Chandralekha et al., 2016 ; Liu et al., 2011 ). Atom C5 is displaced by 0.627 (8) Å with respect to the C2/C3/C4/C6/C7 mean plane, similar to the value observed for 2-[chloro(4-methoxyphenyl)methyl]-2-(4-methoxyphenyl)-5,5-dimethylcyclohexane-1,3-dione (Saloua Chelli et al., 2016 ). The largest endocyclic angle in the cyclohexane ring [C7—C2—C3 = 123.2 (6)°] is located opposite the dithiethan ring and the largest exo-cyclic angle (C6—C7—O2) is 122.3 (5)°. A difference of 1.3° is observed between the angles located on either side of the C1=C2 double bond. In the C₂S₂ ring, the C1—S1 and C1—S2 bond lengths are indistinguishable at 1.716 (6) Å whereas the C8—S1 and C8—S2 bond lengths differ slightly [1.819 (7) and 1.801 (7) Å, respectively]. The molecule has local C_s symmetry with a non-crystallographic mirror plane passing through atoms C8, C1, C2 and C5. The dihedral angle between the cyclohexane (all atoms) and dithietane rings is 9.1 (3)° and short intramolecular S1⋯O2 [2.719 (5) Å] and S2⋯O1 [2.740 (5) Å] contacts are observed (Fig. 1).

Figure 1
The molecular structure of (I)

with displacement ellipsoids drawn at the 50% probability level. The short intramolecular S⋯O contacts are shown as dashed lines.

3. Supramolecular features

In the crystal, the molecules stack head-to-tail along the b-axis direction. The molecules are linked by C5—H5A⋯S2 hydrogen bonds (Table 1) and short [3.165 (5) Å compared to a van der Waals separation of 3.32 Å] S2⋯O2ⁱⁱ [symmetry code: (ii) $[{1\over 2}]$ − x, y, $[{1\over 2}]$ + z] contacts, forming (010) layers (Fig. 2).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5A⋯S2ⁱ	0.97	2.87	3.844 (8)	178
Symmetry code: (i) $[-x, -y+2, z-{\script{1\over 2}}]$ .

Figure 2
Structure of (I)

viewed along the [010] direction, showing the infinite layers propagating parallel to the ac plane. The C—H⋯S and short S⋯O contacts are shown as blue dashed lines.

4. Hirshfeld surface analysis

The nature of the intermolecular interactions in (I) has been computed by CrystalExplorer17.5 (Turner et al., 2017 ), using Hirshfeld surface (HS) analysis (Spackman & Jayatilaka, 2009 ) and two-dimensional fingerprint plots (McKinnon et al., 2007 ). The d_norm plot (Fig. 3) shows red spots corresponding to the C5—H5A⋯S2 hydrogen bond and short S2⋯O2 contact. A list of the relative percentage contributions of the close contacts to the HS of (I) are given in Table 2 and the overall two-dimensional fingerprint plot is shown in Fig. 4a. A contribution of 30.7% was found for the H⋯O/O⋯H interactions, representing the largest contribution; these contacts are represented by the spikes in the top left (d_e > d_i, H⋯O, 14.3%) and bottom right (d_e < d_i, O⋯H, 16.5%) of Fig. 4b. Interactions of the type H⋯H appear in the middle of the scattered points in the fingerprint plots with a pair of spikes at d_e + d_i = 2.5 Å and comprise 25.9% of the entire surface (Fig. 4c); the van der Waals radius for this interaction is 2.4 Å, which means it is a weak interaction. The S⋯H/H⋯S contacts (Fig. 4d), which account for 23.8% of the Hirshfeld surface, are displayed on the fingerprint plot as a pair of long spikes at d_e + d_i = 2.7Å. This distance differs by 0.3 Å from the sum of the van der Waals radii, which means it is the strongest interaction present. The S⋯C/C⋯S (4.0%, Fig. 4f) and S⋯O/O ⋯S (3.3%, Fig. 4g) contacts are seen as pairs of spikes at d_e + d_i = 3.2 and 3.05 Å, respectively. These distances are shorter than the sums of the van der Waals radii of 3.5 and 3.32 Å, respectively. The C⋯O/O⋯C interactions make a contribution of 0.7% to the Hirshfeld surface (Fig. 4h), their interatomic distances (d_e + d_i = 3.3 Å) being larger than the sum of the van der Waals radius (3.22 Å), so this interaction is very weak in this structure. The fingerprint plot corresponding to C⋯H/H⋯C contacts (Fig. 4e) shows a fin-like distribution of points with the edges at d_e + d_i = 2.8 Å.

Table 2
Relative percentage contributions of the close contacts to the Hirshfeld surface of the title compound

Contact type	Percentage contribution
O⋯H/H⋯O	30.7
H⋯H	25.9
S⋯H/H⋯S	23.8
C⋯H/H⋯C	11.6
S⋯C/S⋯C	4.0
S⋯O/O⋯S	3.3
C⋯O/O⋯C	0.7

Figure 3
Hirshfeld surface for (I)

scaled from −0.16 (red) a.u. to 1.09 (blue) a.u.

Figure 4
Two-dimensional finger print plots for (I)

: (a) overall, and delineated into contributions from different contacts: (b) H⋯O/O⋯H, (c) H⋯H, (d) H⋯S/S⋯H, (e) C⋯H/H⋯C, (f) C⋯S/S⋯C, (g) O⋯S/S⋯O and (h) C⋯O/O⋯C.

5. Database survey

A search of the Cambridge Structural Database (CSD, Version 5.43, last update March 2022 ; Groom et al., 2016 ) for the 1,3-dithietane fragment yielded three relevant hits. These are dispiro[1,3-dithietane-2,2′:4,2′′-diadamantane] (CSD refcode AFECAP; Linden et al., 2002 ), trans-2,4-bis(isopropyl)-2,4-bis[(2-methyl-1-thioxo)propylsulfanyl]-1,3-dithietane (HUZHOZ; Mahjoub et al., 2003 ) and 2-(nitromethylene)-1,3-dithietane (WOCQEK; Shanmuga Sundara Raj et al., 2000 ): in these compounds the dithietane ring is planar. In (I), the angles C1—S1—C8 and S1—C8—S2 are 82.7 (3) and 93.6 (3)°, respectively, similar to the values observed for the aforementioned compounds, viz. 85.76 and 94.24°, 85.40 and 94.60°, 82.8 and 94.00° for AFECAP, HUZHOZ and WOCQEK, respectively. A search for the cyclohexane-1,3-dione fragment revealed over 30 hits. The most relevant structures are 2-(phenylaminomethylidene)cyclohexane-1,3-dione (ISUQAO; Kettmann et al., 2004 ), (E)-5,5-dimethyl-2- [3-(4- nitrophenyl)allylidene]cyclohexane-1,3-dione (VUGVUQ; Jae Kyun Lee et al., 2015 ), 2-[chloro(4-methoxyphenyl)methyl]-2-(4-methoxyphenyl)-5,5-dimethylcyclohexane-1,3-dione (TACZIJ; Saloua Chelli et al., 2016) and 2-{(1S*,2S*)-2-[(E)-(2,4-dihydroxybenzylidene)amino]cyclohexyl}isoindoline-1,3-dione (EVABIN; Liu et al., 2011). The cyclohexane ring adopts a chair conformation in all five of these compounds, as in the title compound.

6. Synthesis and crystallization

Potassium carbonate (0.3 mol, 42 g) in DMF (50 ml) was well stirred at room temperature. To this mixture, cyclohexane-1,3-dione (0.1 mol) was added and the resultant solution stirred at room temperature for 20 min. Carbon disulfide (0.15 mol, 9.0 ml) was then added in one lot. The reaction mixture was stirred and kept for 10 min at room temperature. Diiodomethane (0.12 mol) was added dropwise over 20 min and the reaction mixture stirred for 7 h at room temperature. Ice–water (500 ml) was added to the reaction mass, the solid was filtered and washed with water, dried and recrystallized from ethanol solution to give (I) in the form of colourless plates. Yield 81%; m.p. 487 K; UV (H₂O) λ_max, 335 nm (ɛ 18760); IR (KBr, cm⁻¹): 1640 (C=O), ¹H NMR (CDCl₃) δ (ppm): 4.35 (s, 2H, CH₂—S), 2.52 (t, J = 6.5 Hz, 4H, CH₂—CH₂—CH₂), 1.97 (q, J = 6.5 Hz, 2H, CH₂—CH₂—CH₂); ¹³C NMR (CDCl₃) δ (ppm): 197.28 (CO),189.73 (C=C—S), 119.93 (C=C—S), 37.31 (CH₂—CH₂—CH₂), 33.39 (CH₂—S), 18.62 (CH₂—CH₂—CH₂).

7. Refinement

Crystal data, data collection and structure refinement details for the title compound are summarized in Table 3. H atoms were positioned geometrically with C—H = 0.97 Å and refined as riding with U_iso(H) = 1.2U_eq(C).

Table 3
Experimental details

Crystal data
Chemical formula	C₈H₈O₂S₂
M_r	200.28
Crystal system, space group	Orthorhombic, Pca2₁
Temperature (K)	296
a, b, c (Å)	10.7521 (14), 5.5245 (9), 14.480 (2)
V (Å³)	860.1 (2)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	0.57
Crystal size (mm)	0.13 × 0.06 × 0.01

Data collection
Diffractometer	Bruker APEXII
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.960, 0.994
No. of measured, independent and observed [I > 2σ(I)] reflections	3646, 1881, 1230
R_int	0.044
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.051, 0.094, 1.00
No. of reflections	1881
No. of parameters	109
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.34, −0.30
Absolute structure	Flack x determined using 396 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )
Absolute structure parameter	0.04 (8)
Computer programs: APEX2 and (Bruker, 2014 ), SHELXT (Sheldrick, 2015b ), SHELXL2014/7 (Sheldrick, 2015a ) and ORTEP-3 for Windows and WinGX publication routines (Farrugia, 2012 ).

Supporting information

CCDC reference: 2211891

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989022009872/hb8028sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989022009872/hb8028Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2056989022009872/hb8028Isup3.cml

checkCIF report

Computing details top

Data collection: SAINT (Bruker, 2014); cell refinement: APEX2 (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXT (Sheldrick, 2015b); program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2015a); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: WinGX publication routines (Farrugia, 2012).

2-(1,3-Dithietan-2-ylidene)cyclohexane-1,3-dione top

Crystal data top

C₈H₈O₂S₂	F(000) = 416
M_r = 200.28	D_x = 1.547 Mg m⁻³
Orthorhombic, Pca2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2ac	Cell parameters from 772 reflections
a = 10.7521 (14) Å	θ = 3.7–23.4°
b = 5.5245 (9) Å	µ = 0.57 mm⁻¹
c = 14.480 (2) Å	T = 296 K
V = 860.1 (2) Å³	Plate, colorless
Z = 4	0.13 × 0.06 × 0.01 mm

Data collection top

Bruker APEXII diffractometer	1881 independent reflections
Radiation source: fine-focus sealed tube	1230 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.044
CCD rotation images, thick slices scans	θ_max = 27.5°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −9→13
T_min = 0.960, T_max = 0.994	k = −4→7
3646 measured reflections	l = −18→18

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.051	H-atom parameters constrained
wR(F²) = 0.094	w = 1/[σ²(F_o²) + (0.0343P)²] where P = (F_o² + 2F_c²)/3
S = 1.00	(Δ/σ)_max < 0.001
1881 reflections	Δρ_max = 0.34 e Å⁻³
109 parameters	Δρ_min = −0.29 e Å⁻³
1 restraint	Absolute structure: Flack x determined using 396 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
0 constraints	Absolute structure parameter: 0.04 (8)
Primary atom site location: structure-invariant direct methods

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

	x	y	z	U_iso*/U_eq
S1	0.27332 (13)	0.3620 (3)	0.53923 (11)	0.0371 (5)
S2	0.16018 (17)	0.5982 (3)	0.67352 (10)	0.0430 (5)
O1	0.0128 (4)	0.9617 (7)	0.6058 (4)	0.0457 (16)
O2	0.2139 (4)	0.5407 (8)	0.3699 (3)	0.0520 (19)
C1	0.1711 (5)	0.5968 (10)	0.5553 (4)	0.0273 (19)
C2	0.1164 (5)	0.7427 (12)	0.4911 (4)	0.0260 (17)
C3	0.0319 (5)	0.9299 (10)	0.5239 (5)	0.034 (2)
C4	−0.0307 (6)	1.0849 (12)	0.4519 (5)	0.045 (2)
C5	−0.0404 (7)	0.9587 (14)	0.3579 (6)	0.060 (3)
C6	0.0814 (7)	0.8675 (13)	0.3269 (4)	0.058 (3)
C7	0.1416 (6)	0.7004 (12)	0.3941 (4)	0.034 (2)
C8	0.2644 (7)	0.3440 (12)	0.6645 (5)	0.050 (3)
H4A	−0.11352	1.12679	0.47307	0.0542*
H4B	0.01593	1.23405	0.44470	0.0542*
H5A	−0.07254	1.07203	0.31262	0.0722*
H5B	−0.09848	0.82483	0.36241	0.0722*
H6A	0.07063	0.78338	0.26865	0.0697*
H6B	0.13618	1.00398	0.31609	0.0697*
H8A	0.34374	0.37194	0.69448	0.0598*
H8B	0.22773	0.19389	0.68617	0.0598*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S1	0.0410 (8)	0.0394 (9)	0.0308 (8)	0.0115 (8)	0.0003 (9)	0.0007 (9)
S2	0.0561 (11)	0.0509 (10)	0.0219 (7)	0.0117 (9)	0.0005 (8)	−0.0001 (10)
O1	0.052 (3)	0.045 (3)	0.040 (2)	0.011 (2)	0.006 (3)	−0.010 (3)
O2	0.070 (4)	0.058 (3)	0.028 (3)	0.020 (3)	0.008 (3)	−0.001 (2)
C1	0.026 (3)	0.028 (4)	0.028 (3)	−0.006 (2)	0.002 (3)	0.000 (3)
C2	0.027 (3)	0.026 (3)	0.025 (3)	0.002 (3)	−0.001 (3)	0.000 (3)
C3	0.026 (3)	0.032 (4)	0.044 (4)	−0.003 (3)	0.001 (3)	0.004 (3)
C4	0.039 (4)	0.038 (4)	0.059 (4)	0.003 (3)	−0.007 (4)	0.009 (4)
C5	0.064 (6)	0.069 (6)	0.048 (4)	0.013 (4)	−0.014 (4)	0.016 (5)
C6	0.061 (5)	0.072 (5)	0.041 (4)	0.020 (4)	0.010 (4)	0.024 (4)
C7	0.035 (4)	0.039 (4)	0.028 (3)	−0.002 (3)	0.003 (3)	0.005 (3)
C8	0.064 (5)	0.052 (5)	0.034 (4)	0.014 (3)	−0.006 (4)	0.006 (4)

Geometric parameters (Å, º) top

S1—C1	1.716 (6)	C5—C6	1.473 (11)
S1—C8	1.819 (7)	C6—C7	1.489 (9)
S2—C1	1.716 (6)	C4—H4A	0.9700
S2—C8	1.801 (7)	C4—H4B	0.9700
O1—C3	1.216 (9)	C5—H5A	0.9700
O2—C7	1.227 (8)	C5—H5B	0.9700
C1—C2	1.364 (8)	C6—H6A	0.9700
C2—C3	1.456 (8)	C6—H6B	0.9700
C2—C7	1.449 (8)	C8—H8A	0.9700
C3—C4	1.508 (9)	C8—H8B	0.9700
C4—C5	1.533 (11)

C1—S1—C8	82.7 (3)	C3—C4—H4B	109.00
C1—S2—C8	83.2 (3)	C5—C4—H4A	109.00
S1—C1—S2	100.5 (3)	C5—C4—H4B	109.00
S1—C1—C2	129.1 (5)	H4A—C4—H4B	108.00
S2—C1—C2	130.4 (5)	C4—C5—H5A	109.00
C1—C2—C3	117.8 (5)	C4—C5—H5B	109.00
C1—C2—C7	119.0 (6)	C6—C5—H5A	109.00
C3—C2—C7	123.2 (6)	C6—C5—H5B	109.00
O1—C3—C2	121.7 (6)	H5A—C5—H5B	108.00
O1—C3—C4	121.1 (5)	C5—C6—H6A	109.00
C2—C3—C4	117.2 (6)	C5—C6—H6B	109.00
C3—C4—C5	112.7 (6)	C7—C6—H6A	109.00
C4—C5—C6	111.5 (6)	C7—C6—H6B	109.00
C5—C6—C7	113.5 (6)	H6A—C6—H6B	108.00
O2—C7—C2	120.7 (6)	S1—C8—H8A	113.00
O2—C7—C6	122.3 (5)	S1—C8—H8B	113.00
C2—C7—C6	116.9 (6)	S2—C8—H8A	113.00
S1—C8—S2	93.6 (3)	S2—C8—H8B	113.00
C3—C4—H4A	109.00	H8A—C8—H8B	110.00

C8—S1—C1—S2	1.5 (3)	C1—C2—C3—C4	−178.3 (5)
C8—S1—C1—C2	−179.6 (6)	C1—C2—C7—C6	−178.9 (6)
C1—S1—C8—S2	−1.4 (3)	C3—C2—C7—O2	179.8 (6)
C8—S2—C1—S1	−1.5 (3)	C1—C2—C7—O2	−2.2 (9)
C8—S2—C1—C2	179.6 (6)	C1—C2—C3—O1	2.2 (8)
C1—S2—C8—S1	1.4 (3)	C3—C2—C7—C6	3.1 (9)
S2—C1—C2—C3	−1.6 (9)	C2—C3—C4—C5	24.6 (8)
S1—C1—C2—C3	179.8 (4)	O1—C3—C4—C5	−155.8 (6)
S1—C1—C2—C7	1.6 (9)	C3—C4—C5—C6	−52.6 (8)
S2—C1—C2—C7	−179.7 (5)	C4—C5—C6—C7	56.3 (8)
C7—C2—C3—O1	−179.8 (6)	C5—C6—C7—C2	−31.5 (9)
C7—C2—C3—C4	−0.2 (8)	C5—C6—C7—O2	151.8 (6)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5A···S2ⁱ	0.97	2.87	3.844 (8)	178

Symmetry code: (i) −x, −y+2, z−1/2.

Relative percentage contributions of the close contacts to the Hirshfeld surface of the title compound top

Contact type	Percentage contribution
O···H/H···O	30.7
H···H	25.9
S···H/H···S	23.8
C···H/H···C	11.6
S···C/S···C	4.0
S···O/O···S	3.3
C···O/O···C	0.7

Acknowledgements

We thank the Diffractometry Center of the University of Rennes 1 for collecting the X-ray diffraction data.

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