research communications
H-anthra[1,2-b][1,4]dioxepine-8,13-dione
and Hirshfeld surface analysis of 3,4-dihydro-2aLaboratory of Sustainable Development, Sultan Moulay Slimane University, Faculty of Sciences and Technologies, BP 523, 23000 Beni-Mellal, Morocco, bLaboratory of Organic and Analytical Chemistry, University Sultan Moulay Slimane, Faculty of Science and Technology, PO Box 523, Beni-Mellal, Morocco, and cMolecular Tectonics Laboratory, Université de Strasbourg, CNRS, CMC UMR 7140, F-67000 Strasbourg, France
*Correspondence e-mail: szazouli@gmail.com
The title compound, C17H12O4, was synthesized from the dye alizarin. The dihedral angle between the mean plane of the anthraquinone ring system (r.m.s. deviation = 0.039 Å) and the dioxepine ring is 16.29 (8)°. In the crystal, the molecules are linked by C—H⋯O hydrogen bonds, forming sheets lying parallel to the ab plane. The sheets are connected through π–π and C=O⋯π interactions to generate a three-dimensional supramolecular network. Hirshfeld surface analysis was used to investigate intermolecular interactions in the solid-state: the most important contributions are from H⋯H (43.0%), H⋯O/O⋯H (27%), H⋯C/C⋯H (13.8%) and C⋯C (12.4%) contacts.
CCDC reference: 1991271
1. Chemical context
Anthraquinone derivatives, which are extracted from the seeds of the Rubiaceae family of shrubs, include alizarin (1,2-dihydroxyanthraquinone; C14H8O4) and other polycyclic aromatic hydrocarbons. The colour of anthraquinone-based compounds can be modified by the type and position of the substituents attached to the anthraquinone nucleus (Nakagawa et al. 2017; Cheuk et al., 2015; Tonin et al., 2017). Besides their application as pigments or dyes in textile, photographic, cosmetic and other industries (Wang et al., 2011), anthraquinone derivatives have been used for centuries for medical applications, for example, as laxatives (Oshio et al., 1985), antioxidants (Yen et al., 2000), antimicrobial (Xiang et al., 2008; Yadav et al., 2010) and anitiviral (Alves et al., 2004) agents. Their redox properties and cytotoxicity have been investigated recently (Okumura et al., 2019). Anthraquinone derivatives exhibit various applications in supramolecular and electro-analytical chemistry (Czupryniak et al., 2012).
As part of our studies in this area, the synthesis and structure of the title compound, (I), are described along with a detailed analysis of its supramolecular associations through an analysis of the Hirshfeld surfaces.
2. Structural commentary
Compound (I) crystallizes in P21/n with one molecule in the it consists of three fused six-membered rings and one seven-membered ring as shown in Fig. 1. The fused-ring system is close to planar with an r.m.s. deviation for all non-hydrogen atoms of 0.039 Å (the dihedral angle between the aromatic rings of the anthraquinone unit and the central ring range from 1.5 to 1.9°). The dioxepine ring is inclined to the mean plane of the anthraquinone ring system by 16.29 (8)°.
A puckering analysis of the seven-membered ring yielded the parameters q2 = 0.896 (2) Å, φ2 = 113.50 (12)°, q3 = 0.358 (2) Å, and φ3 = 217.8 (3)°. These metrics indicate that the ring adopts a screw boat conformation. The C—O and C=O bond lengths lie within the ranges 1.355 (2)–1.457 (2) Å and 1.216 (2)–1.226 (2) Å, respectively, confirming their single and double-bond character.
3. Supramolecular features
In the extended structure of (I), C15—H15B⋯O1 hydrogen bonds form inversion dimers with an R22(14) ring motif. Adjacent dimers are linked by C15—H15A⋯O3 contacts, thereby generating corrugated chains of molecules (Fig. 2a). A C17—H17B⋯O2 hydrogen bond links the chains together (Table 1; Fig. 2b and 2c), forming sheets propagating in the ab plane. These sheets are supported by extensive π–π contacts between adjacent rings, with centroid-to-centroid distances Cg1⋯Cg2 = 3.599 (2) and Cg2⋯Cg3 = 3.683 (2) Å [Cg1, Cg2 and Cg3 are the centroids of the rings C1–C4/C13–C14, C4–C6/C11–C13 and C6–C11, respectively] and weak C12=O1⋯π [oxygen–centroid distance = 3.734 (2) Å] interactions (Fig. 3), linking the slabs to form a three-dimensional supramolecular network.
4. Database survey
A search in the Cambridge Structural Database (CSD, Version 5.40, updated to February 2020; Groom et al., 2016) revealed 55 alizarin-ring motifs incorporated in more complex molecules or bearing functional groups. These include several compounds with a different substituent in place of the dioxepine in the title compound, viz. 1-hydroxy-2-methoxy-6-methyl (BOTXUE; Ismail et al., 2009), 1,2-dimethoxy (refcode: KIBHUZ; Kar et al., 2007) and 3-hydroxy-1,2-dimethoxy (BOVVEO; Xu et al., 2009). In these compounds, the anthraquinone ring system are almost planar, the dihedral angle between the benzene rings for BOTXUE, KIBHUZ and BOVVEO being 3.49, 2.83 and 1.12°, respectively. The methoxy groups in position 1 (C14) in KIBHUZ and BOVVEO are almost perpendicular to the anthraquinone ring plane. The other compound belongs to the same class of alizarins with different substituents.
5. Hirshfeld surface analysis
The nature of the intermolecular interactions in (I) have been examined with CrystalExplorer17.5 (Turner et al., 2017), using Hirshfeld surface analysis (Spackman & Jayatilaka, 2009) mapped over dnorm, with a fixed colour scale of −0.1779 to 1.3612 a.u (see Fig. S1a in the supporting information) and two-dimensional fingerprint plots (McKinnon et al., 2007). The intense red spots on the surface are due to the C—H⋯O hydrogen bonds (Fig. 4). Fig. S2 (supporting information) shows the molecular electrostatic potential surface generated using TONTO with a STO-3G basis set in the range −0.050 to 0.050 a.u. within the Hartree–Fock level of theory. Molecular sites evidenced in red correspond to positive and in blue to negative (Spackman et al., 2008).
As illustrated in Fig. 5, the overall fingerprint plot for (I) and those delineated into H⋯H, H⋯O/O⋯H, C⋯H/H⋯C and C⋯C show characteristic pseudo-symmetric wings in the de and di diagonal axes. The most important interaction is H⋯H, contributing 43% to the overall crystal packing, which is reflected in Fig. 5b as widely scattered points of high density due to the large hydrogen content of the molecule, with small split tips at de ≃ di ≃ 1.2 Å. The contribution from the O⋯H/H⋯O contacts (27%) [note that the O⋯H interactions make a larger contribution (14.6%) than the H⋯O interactions (12.4%)], corresponding to C—H⋯O interactions, is represented by a pair of sharp spikes characteristic of a strong hydrogen-bond interaction, de + di ≃ 2.35 Å (Fig. 5c). The significant contribution from C⋯H/H⋯C contacts (13.8%) to the Hirshfeld surface of (I) reflect the short C⋯H/H⋯C contacts, and the distribution of points has characteristic wings, Fig. 5d, with de + di ≃2.55 Å. The distribution of points in the de = di ≃ 1.75 Å range in the fingerprint plot delineated into C⋯C contacts indicates the existence of weak π–π stacking interactions between the central anthracene ring and the C6–C11 and C1–C4/C13–C14 rings (Fig. 4b and 5e). Aromatic π–π interactions are indicated by adjacent red and blue triangles in the shape-index map (Fig. S1b)and also by the flat region around these rings in the Hirshfeld surfaces mapped over curvedness in Fig. S1c.
The contribution of 3.2% from C⋯O/O⋯C contacts is due to the presence of short interatomic C=O⋯π contacts, and is apparent as the pair of parabolic tips at de + di ≃ 3.2 Å in Fig. 5f.
6. Synthesis and crystallization
Under argon, alizarin (0.50 g, 2.0 mmol) was treated with 1,3-dibromo-propane (0.42 g, 2.0 mmol) in dimethylformamide (30 ml) in the presence of anhydrous potassium carbonate (1.0 g, 7.2 mmol) with stirring and heated to 393 K for 24 h. The reaction mixture was evaporated to dryness under vacuum and the resulting crude product was acidified with 12 N hydrochloric acid, extracted with chloroform (3 × 30 ml) and then chromatographed on a silica gel column with dichloromethane/petroleum ether (1/1) as which yielded 200 mg (35%) of 1,2-propylenedioxyanthraquinone as a yellow compound (Fig. 6). Colourless needles were obtained by slow evaporation of a dichloromethane/petroleum ether (1:1) solution.
1H NMR (CDCl3, 500 MHz): δ (ppm): 8.21 (m, 2H), 7.95 (d, J = 8.5 Hz, 1H), 7.72 (m, 2H), 7.26 (d, J = 8.5 Hz, 1H), 4.48 (t, J = 6 Hz, 2H), 4.43 (t, J = 6 Hz, 2H), 2.34 (qt, J = 6 Hz, 2H); 13C NMR (CDCl3, 126 MHz): δ (ppm): 182.9, 182.5, 157.3, 151.3, 135.2, 133.9, 133.4, 132.6, 129.6, 127.1, 126.5, 126.0, 125.9, 123.3, 70.5, 70.2, 30.0. Analysis calculated for C17H12O4: C, 72.85%; H, 4.32%; found: C, 72.82%; H, 4.29%.
7. Refinement
Crystal data, data collection and structure . H atoms were placed in calculated positions and refined in the riding model: C—H = 0.95–0.99 Å with Uiso(H) = 1.2Ueq(C). The reflection (011), affected by the beam-stop, was removed during refinement.
details are summarized in Table 2Supporting information
CCDC reference: 1991271
https://doi.org/10.1107/S2056989020003965/hb7899sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989020003965/hb7899Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2056989020003965/hb7899Isup3.cml
Supplementary figures: Hirshfeld surface analysis. DOI: https://doi.org/10.1107/S2056989020003965/hb7899sup4.docx
Data collection: APEX2 (Bruker, 2012); cell
SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); program(s) used to solve structure: SHELXT2014/5 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg et al., 2012); software used to prepare material for publication: PLATON (Spek, 2020) and publCIF (Westrip, 2010).C17H12O4 | F(000) = 584 |
Mr = 280.27 | Dx = 1.439 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 4.2951 (2) Å | Cell parameters from 3436 reflections |
b = 16.7714 (9) Å | θ = 2.4–29.7° |
c = 18.0537 (11) Å | µ = 0.10 mm−1 |
β = 95.941 (2)° | T = 173 K |
V = 1293.51 (12) Å3 | Prism, colorless |
Z = 4 | 0.12 × 0.10 × 0.10 mm |
Bruker APEXII CCD diffractometer | 2309 reflections with I > 2σ(I) |
φ and ω scans | Rint = 0.044 |
Absorption correction: multi-scan (SADABS; Bruker, 2012) | θmax = 29.7°, θmin = 2.4° |
Tmin = 0.988, Tmax = 0.990 | h = −5→4 |
19692 measured reflections | k = −23→23 |
3436 independent reflections | l = −24→25 |
Refinement on F2 | Primary atom site location: dual |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.055 | H-atom parameters constrained |
wR(F2) = 0.149 | w = 1/[σ2(Fo2) + (0.0548P)2 + 0.8849P] where P = (Fo2 + 2Fc2)/3 |
S = 1.02 | (Δ/σ)max < 0.001 |
3436 reflections | Δρmax = 0.41 e Å−3 |
190 parameters | Δρmin = −0.32 e Å−3 |
0 restraints |
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 | ||
O1 | −0.2635 (5) | 0.49906 (10) | 0.64736 (8) | 0.0546 (5) | |
O2 | 0.1717 (4) | 0.34277 (9) | 0.89646 (7) | 0.0449 (4) | |
O3 | 0.0471 (3) | 0.40325 (8) | 0.56747 (6) | 0.0293 (3) | |
O4 | 0.4204 (4) | 0.25897 (8) | 0.56830 (7) | 0.0356 (3) | |
C1 | 0.3367 (5) | 0.29496 (11) | 0.63141 (10) | 0.0274 (4) | |
C2 | 0.4523 (5) | 0.26018 (11) | 0.69817 (11) | 0.0321 (4) | |
H2 | 0.590316 | 0.215932 | 0.697909 | 0.038* | |
C3 | 0.3704 (5) | 0.28874 (11) | 0.76486 (10) | 0.0302 (4) | |
H3 | 0.451085 | 0.264092 | 0.810209 | 0.036* | |
C4 | 0.1701 (4) | 0.35347 (10) | 0.76600 (9) | 0.0244 (4) | |
C5 | 0.0822 (5) | 0.37964 (11) | 0.83960 (10) | 0.0285 (4) | |
C6 | −0.1143 (5) | 0.45162 (10) | 0.84226 (9) | 0.0269 (4) | |
C7 | −0.1904 (5) | 0.47948 (12) | 0.91105 (10) | 0.0351 (5) | |
H7 | −0.121046 | 0.451264 | 0.955331 | 0.042* | |
C8 | −0.3662 (6) | 0.54788 (13) | 0.91472 (11) | 0.0407 (5) | |
H8 | −0.413992 | 0.567394 | 0.961621 | 0.049* | |
C9 | −0.4731 (5) | 0.58819 (12) | 0.85004 (11) | 0.0377 (5) | |
H9 | −0.595642 | 0.635045 | 0.852781 | 0.045* | |
C10 | −0.4023 (5) | 0.56056 (11) | 0.78134 (11) | 0.0308 (4) | |
H10 | −0.478159 | 0.588130 | 0.737151 | 0.037* | |
C11 | −0.2198 (4) | 0.49227 (10) | 0.77718 (9) | 0.0248 (4) | |
C12 | −0.1467 (5) | 0.46397 (10) | 0.70231 (9) | 0.0271 (4) | |
C13 | 0.0595 (4) | 0.39292 (10) | 0.69919 (9) | 0.0227 (4) | |
C14 | 0.1495 (4) | 0.36425 (10) | 0.63107 (9) | 0.0238 (4) | |
C15 | 0.2543 (5) | 0.40456 (12) | 0.50847 (10) | 0.0331 (4) | |
H15A | 0.474823 | 0.405280 | 0.530766 | 0.040* | |
H15B | 0.216063 | 0.453607 | 0.478396 | 0.040* | |
C16 | 0.1997 (6) | 0.33217 (13) | 0.45871 (11) | 0.0389 (5) | |
H16A | 0.001584 | 0.338786 | 0.426047 | 0.047* | |
H16B | 0.372274 | 0.327239 | 0.426649 | 0.047* | |
C17 | 0.1829 (6) | 0.25735 (13) | 0.50493 (11) | 0.0384 (5) | |
H17A | −0.026930 | 0.253140 | 0.522692 | 0.046* | |
H17B | 0.214839 | 0.210027 | 0.473818 | 0.046* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0835 (14) | 0.0550 (10) | 0.0254 (7) | 0.0370 (9) | 0.0062 (8) | 0.0053 (6) |
O2 | 0.0590 (12) | 0.0499 (9) | 0.0257 (7) | 0.0106 (8) | 0.0036 (7) | 0.0110 (6) |
O3 | 0.0301 (8) | 0.0378 (7) | 0.0201 (6) | 0.0062 (6) | 0.0029 (5) | 0.0009 (5) |
O4 | 0.0345 (9) | 0.0386 (8) | 0.0346 (7) | 0.0062 (6) | 0.0078 (6) | −0.0075 (6) |
C1 | 0.0248 (10) | 0.0272 (9) | 0.0307 (9) | −0.0022 (7) | 0.0053 (7) | −0.0040 (7) |
C2 | 0.0296 (11) | 0.0267 (9) | 0.0394 (10) | 0.0036 (7) | 0.0010 (8) | 0.0015 (7) |
C3 | 0.0297 (11) | 0.0283 (9) | 0.0313 (9) | 0.0005 (7) | −0.0030 (8) | 0.0054 (7) |
C4 | 0.0245 (10) | 0.0230 (8) | 0.0252 (8) | −0.0033 (7) | 0.0002 (7) | 0.0022 (6) |
C5 | 0.0314 (11) | 0.0298 (9) | 0.0237 (8) | −0.0042 (7) | 0.0002 (7) | 0.0022 (7) |
C6 | 0.0309 (11) | 0.0278 (8) | 0.0220 (8) | −0.0070 (7) | 0.0025 (7) | −0.0014 (6) |
C7 | 0.0445 (14) | 0.0376 (10) | 0.0238 (9) | −0.0053 (9) | 0.0064 (8) | −0.0010 (7) |
C8 | 0.0538 (16) | 0.0407 (11) | 0.0295 (10) | −0.0035 (10) | 0.0143 (9) | −0.0078 (8) |
C9 | 0.0429 (14) | 0.0317 (10) | 0.0402 (11) | 0.0007 (9) | 0.0126 (9) | −0.0054 (8) |
C10 | 0.0342 (12) | 0.0264 (9) | 0.0322 (9) | −0.0008 (7) | 0.0054 (8) | −0.0002 (7) |
C11 | 0.0274 (10) | 0.0233 (8) | 0.0239 (8) | −0.0051 (7) | 0.0027 (7) | −0.0011 (6) |
C12 | 0.0304 (11) | 0.0274 (9) | 0.0234 (8) | 0.0015 (7) | 0.0015 (7) | 0.0006 (6) |
C13 | 0.0233 (10) | 0.0213 (8) | 0.0231 (8) | −0.0039 (6) | 0.0010 (6) | 0.0006 (6) |
C14 | 0.0218 (10) | 0.0255 (8) | 0.0236 (8) | −0.0033 (7) | 0.0005 (7) | −0.0003 (6) |
C15 | 0.0353 (12) | 0.0407 (11) | 0.0246 (9) | 0.0002 (8) | 0.0085 (8) | 0.0014 (7) |
C16 | 0.0396 (14) | 0.0525 (12) | 0.0256 (9) | 0.0027 (10) | 0.0080 (8) | −0.0079 (8) |
C17 | 0.0376 (13) | 0.0428 (11) | 0.0357 (10) | −0.0027 (9) | 0.0078 (9) | −0.0145 (8) |
O1—C12 | 1.216 (2) | C7—H7 | 0.9500 |
O2—C5 | 1.226 (2) | C8—C9 | 1.386 (3) |
O3—C14 | 1.355 (2) | C8—H8 | 0.9500 |
O3—C15 | 1.457 (2) | C9—C10 | 1.387 (3) |
O4—C1 | 1.370 (2) | C9—H9 | 0.9500 |
O4—C17 | 1.452 (3) | C10—C11 | 1.394 (3) |
C1—C2 | 1.384 (3) | C10—H10 | 0.9500 |
C1—C14 | 1.413 (3) | C11—C12 | 1.496 (2) |
C2—C3 | 1.375 (3) | C12—C13 | 1.489 (2) |
C2—H2 | 0.9500 | C13—C14 | 1.411 (2) |
C3—C4 | 1.387 (3) | C15—C16 | 1.514 (3) |
C3—H3 | 0.9500 | C15—H15A | 0.9900 |
C4—C13 | 1.414 (2) | C15—H15B | 0.9900 |
C4—C5 | 1.485 (2) | C16—C17 | 1.513 (3) |
C5—C6 | 1.477 (3) | C16—H16A | 0.9900 |
C6—C11 | 1.393 (2) | C16—H16B | 0.9900 |
C6—C7 | 1.397 (2) | C17—H17A | 0.9900 |
C7—C8 | 1.379 (3) | C17—H17B | 0.9900 |
C14—O3—C15 | 117.23 (15) | C11—C10—H10 | 120.0 |
C1—O4—C17 | 116.12 (16) | C6—C11—C10 | 119.49 (16) |
O4—C1—C2 | 115.92 (17) | C6—C11—C12 | 121.76 (16) |
O4—C1—C14 | 123.85 (16) | C10—C11—C12 | 118.75 (15) |
C2—C1—C14 | 120.22 (16) | O1—C12—C13 | 123.57 (16) |
C3—C2—C1 | 120.95 (18) | O1—C12—C11 | 118.43 (17) |
C3—C2—H2 | 119.5 | C13—C12—C11 | 117.99 (14) |
C1—C2—H2 | 119.5 | C14—C13—C4 | 119.06 (16) |
C2—C3—C4 | 120.08 (17) | C14—C13—C12 | 121.55 (15) |
C2—C3—H3 | 120.0 | C4—C13—C12 | 119.39 (15) |
C4—C3—H3 | 120.0 | O3—C14—C13 | 118.68 (15) |
C3—C4—C13 | 120.52 (16) | O3—C14—C1 | 122.38 (15) |
C3—C4—C5 | 117.40 (15) | C13—C14—C1 | 118.92 (15) |
C13—C4—C5 | 122.07 (16) | O3—C15—C16 | 110.66 (16) |
O2—C5—C6 | 121.06 (17) | O3—C15—H15A | 109.5 |
O2—C5—C4 | 120.92 (18) | C16—C15—H15A | 109.5 |
C6—C5—C4 | 118.02 (15) | O3—C15—H15B | 109.5 |
C11—C6—C7 | 120.04 (18) | C16—C15—H15B | 109.5 |
C11—C6—C5 | 120.65 (16) | H15A—C15—H15B | 108.1 |
C7—C6—C5 | 119.31 (16) | C17—C16—C15 | 110.55 (16) |
C8—C7—C6 | 120.04 (18) | C17—C16—H16A | 109.5 |
C8—C7—H7 | 120.0 | C15—C16—H16A | 109.5 |
C6—C7—H7 | 120.0 | C17—C16—H16B | 109.5 |
C7—C8—C9 | 120.06 (18) | C15—C16—H16B | 109.5 |
C7—C8—H8 | 120.0 | H16A—C16—H16B | 108.1 |
C9—C8—H8 | 120.0 | O4—C17—C16 | 110.46 (18) |
C8—C9—C10 | 120.42 (19) | O4—C17—H17A | 109.6 |
C8—C9—H9 | 119.8 | C16—C17—H17A | 109.6 |
C10—C9—H9 | 119.8 | O4—C17—H17B | 109.6 |
C9—C10—C11 | 119.94 (18) | C16—C17—H17B | 109.6 |
C9—C10—H10 | 120.0 | H17A—C17—H17B | 108.1 |
D—H···A | D—H | H···A | D···A | D—H···A |
C15—H15B···O1i | 0.99 | 2.43 | 3.248 (2) | 139 |
C15—H15A···O3ii | 0.99 | 2.48 | 3.461 (3) | 171 |
C17—H17A···O4iii | 0.99 | 2.59 | 3.580 (3) | 174 |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) x+1, y, z; (iii) x−1, y, z. |
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