2,3,6,7-Tetra­meth­oxy-9,10-anthra­quinone

Ohta, A.; Hattori, K.; Kawase, T.; Kobayashi, T.; Naito, H.; Kitamura, C.

doi:10.1107/S1600536812033119

organic compounds

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ISSN: 2056-9890

Volume 68| Part 8| August 2012| Page o2587

https://doi.org/10.1107/S1600536812033119

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2,3,6,7-Tetramethoxy-9,10-anthraquinone

Akira Ohta,^a Kazuki Hattori,^a Takeshi Kawase,^b Takashi Kobayashi,^c Hiroyoshi Naito ^c and Chitoshi Kitamura ^b ^*

^aDepartment of Chemistry, Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan, ^bDepartment of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan, and ^cDepartment of Physics and Electronics, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuencho, Naka-ku, Sakai, Osaka 599-8531, Japan
^*Correspondence e-mail: kitamura@eng.u-hyogo.ac.jp

(Received 13 July 2012; accepted 21 July 2012; online 28 July 2012)

Molecules of the title compound, C₁₈H₁₆O₆, are almost planar [maximum deviation = 0.096 (4) Å] and reside on crystallographic centres of inversion. They adopt a conformation in which the C_methyl—O bonds are directed along the molecular short axis [C—C—O—C torsion angles of −175.3 (3) and 178.2 (3)°]. In the crystal, molecules adopt a slipped-parallel arrangement with π–π stacking interactions along the a axis with an interplanar distance of 3.392 (4) Å. Weak C—H⋯O interactions link the molecules into sheets parallel to (10 $[\overline{2}]$ ).

Related literature

For a study of the effects of alkoxy substituents on the structures and solid-state photophysics, see: Ohta et al. (2012 ). For the synthesis, see: Boldt (1967 ). For a related structure, see: Kitamura et al. (2009 ).

Experimental

Crystal data

C₁₈H₁₆O₆
M_r = 328.31
Triclinic, $[P \overline 1]$
a = 4.6607 (4) Å
b = 8.4769 (9) Å
c = 9.8110 (9) Å
α = 94.859 (3)°
β = 91.410 (2)°
γ = 97.278 (2)°
V = 382.87 (6) Å³
Z = 1
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 223 K
0.50 × 0.06 × 0.05 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
3738 measured reflections
1725 independent reflections
977 reflections with I > 2σ(I)
R_int = 0.027

Refinement

R[F² > 2σ(F²)] = 0.054
wR(F²) = 0.234
S = 1.16
1725 reflections
111 parameters
H-atom parameters constrained
Δρ_max = 0.39 e Å⁻³
Δρ_min = −0.44 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C8—H8A⋯O1ⁱ	0.97	2.58	3.391 (5)	142
C9—H9B⋯O2ⁱⁱ	0.97	2.54	3.494 (4)	168
Symmetry codes: (i) -x, -y, -z; (ii) -x+2, -y+1, -z+1.

Data collection: RAPID-AUTO (Rigaku, 1999 ); cell refinement: PROCESS-AUTO (Rigaku, 1998 ); data reduction: PROCESS-AUTO; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536812033119/gg2091sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812033119/gg2091Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S1600536812033119/gg2091Isup3.cml

checkCIF report

Comment top

9,10-Anthraquinone is an important molecule in the field of industrial dyes. We have recently been interested in the tuning of the solid-state optical properties by the introduction of substituents. As part of our program aimed at the elucidation of the effects of alkoxy substituents on the optical properties in the solid state (Ohta, et al., 2012), we are in need of the information on the crystal structures of a variety of 2,3,6,7-tetraalkoxy-9,10-anthraquinones in order to clarify the correlation between crystal structures and the solid-state photophysics. Although the title compound is already known (Boldt, 1967), the X-ray structure was not reported to date. We report herein the crystal structure of the title compound (I).

The molecular structure of the title compound (I) is shown in Fig. 1. The molecule possesses a center of inversion, and half of the formula unit is crystallographically independent. The molecule is almost planar with the maximum deviation of 0.096 (4) Å for C8. The displacements of atoms O1, O2, O3, C8 and C9 relative to the plane of the anthraquinone framework are 0.023 (2), -0.002 (2), 0.013 (2), 0.096 (4), and 0.060 (3), respectively. The molecule prefers the conformation in which the C_methyl—O bonds are directed along the molecular short axis. The torsion angles of C3—C2—O2—C8 and C2—C3—O3—C9 are -175.3 (3) and 178.2 (3)°, respectively. This conformation is similar to the corresponding moiety in 2,3-dimethoxy-5,12-tetracenequinone (Kitamura, et al., 2009). The molecules adopt a slipped-parallel arrangement as shown in Fig. 2. Then molecules are π-stacked along the a axis with an interplanar distance 3.392 (4) Å.

To examine the influence of crystal packing on the solid-state fluorescences, the fluorescence spectrum and the absolute quantum yield of (I) were measured with a Hamamatsu Photonics PMA11 calibrated optical multichannel analyzer with a solid-state blue laser (λ_ex = 377 nm) and a Labsphere IS IS-040-SF integrating sphere, respectively. The crystals showed negligible fluorescence (Φ = 0.002). The fluorescence quenching would be due to the π-stacked structure.

Related literature top

For a study of the effects of alkoxy substituents on the structures and solid-state photophysics, see: Ohta et al. (2012). For the synthesis, see: Boldt (1967). For a related structure, see: Kitamura et al. (2009).

Experimental top

The title compound was prepared according to the literature procedure (Boldt, 1967). Single crystals suitable for X-ray analysis were obtained by recrystallization from DMF.

Structure description top

For a study of the effects of alkoxy substituents on the structures and solid-state photophysics, see: Ohta et al. (2012). For the synthesis, see: Boldt (1967). For a related structure, see: Kitamura et al. (2009).

Computing details top

Data collection: RAPID-AUTO (Rigaku, 1999); cell refinement: PROCESS-AUTO (Rigaku, 1998); data reduction: PROCESS-AUTO (Rigaku, 1998); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top

	Fig. 1. The molecular structure of the title compound (I), showing the atomic numbering numbering and 30% probability displacement ellipsoids. Symmetry code: (i) -x, -y + 1, -z.
	Fig. 2. The packing diagram of (I). Hydrogen atoms are omitted for clarity.

2,3,6,7-Tetramethoxy-9,10-anthraquinone top

Crystal data top

C₁₈H₁₆O₆	Z = 1
M_r = 328.31	F(000) = 172
Triclinic, P1	D_x = 1.424 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.6607 (4) Å	Cell parameters from 1977 reflections
b = 8.4769 (9) Å	θ = 3.1–27.5°
c = 9.8110 (9) Å	µ = 0.11 mm⁻¹
α = 94.859 (3)°	T = 223 K
β = 91.410 (2)°	Needle, yellow
γ = 97.278 (2)°	0.50 × 0.06 × 0.05 mm
V = 382.87 (6) Å³

Data collection top

Rigaku R-AXIS RAPID diffractometer	977 reflections with I > 2σ(I)
Radiation source: fine-focus sealed x-ray tube	R_int = 0.027
Graphite monochromator	θ_max = 27.5°, θ_min = 3.1°
Detector resolution: 10 pixels mm^-1	h = −6→5
ω scans	k = −10→10
3738 measured reflections	l = −12→12
1725 independent reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.054	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.234	H-atom parameters constrained
S = 1.16	w = 1/[σ²(F_o²) + (0.1038P)² + 0.301P] where P = (F_o² + 2F_c²)/3
1725 reflections	(Δ/σ)_max < 0.001
111 parameters	Δρ_max = 0.39 e Å⁻³
0 restraints	Δρ_min = −0.44 e Å⁻³

Crystal data top

C₁₈H₁₆O₆	γ = 97.278 (2)°
M_r = 328.31	V = 382.87 (6) Å³
Triclinic, P1	Z = 1
a = 4.6607 (4) Å	Mo Kα radiation
b = 8.4769 (9) Å	µ = 0.11 mm⁻¹
c = 9.8110 (9) Å	T = 223 K
α = 94.859 (3)°	0.50 × 0.06 × 0.05 mm
β = 91.410 (2)°

Data collection top

Rigaku R-AXIS RAPID diffractometer	977 reflections with I > 2σ(I)
3738 measured reflections	R_int = 0.027
1725 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.054	0 restraints
wR(F²) = 0.234	H-atom parameters constrained
S = 1.16	Δρ_max = 0.39 e Å⁻³
1725 reflections	Δρ_min = −0.44 e Å⁻³
111 parameters

Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > 2σ(F²) is used only for calculating R-factors(gt) 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

	x	y	z	U_iso*/U_eq
C1	0.3162 (6)	0.2759 (3)	0.1180 (3)	0.0304 (7)
H1	0.2882	0.1685	0.082	0.036*
C2	0.5104 (6)	0.3236 (3)	0.2269 (3)	0.0282 (7)
C3	0.5524 (6)	0.4852 (3)	0.2811 (3)	0.0279 (6)
C4	0.3981 (6)	0.5939 (3)	0.2252 (3)	0.0293 (7)
H4	0.425	0.7012	0.2616	0.035*
C5	0.2021 (6)	0.5460 (3)	0.1150 (3)	0.0264 (6)
C6	0.1606 (6)	0.3872 (3)	0.0611 (3)	0.0274 (6)
C7	−0.0418 (6)	0.3343 (3)	−0.0564 (3)	0.0286 (6)
O1	−0.0753 (5)	0.1938 (3)	−0.1056 (2)	0.0421 (6)
C8	0.6538 (9)	0.0647 (4)	0.2327 (4)	0.0529 (10)
H8A	0.4579	0.0121	0.2389	0.079*
H8B	0.7865	0.0095	0.2828	0.079*
H8C	0.7052	0.0628	0.1374	0.079*
O2	0.6714 (5)	0.2264 (2)	0.2899 (2)	0.0369 (6)
C9	0.8062 (7)	0.6813 (4)	0.4442 (3)	0.0382 (8)
H9A	0.8839	0.7476	0.3745	0.057*
H9B	0.946	0.6892	0.5202	0.057*
H9C	0.6283	0.7173	0.4764	0.057*
O3	0.7479 (5)	0.5185 (2)	0.3876 (2)	0.0345 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0295 (15)	0.0273 (15)	0.0345 (15)	0.0050 (11)	−0.0052 (12)	0.0030 (12)
C2	0.0270 (14)	0.0262 (14)	0.0325 (14)	0.0079 (11)	−0.0031 (12)	0.0033 (11)
C3	0.0277 (14)	0.0278 (15)	0.0280 (14)	0.0026 (11)	−0.0024 (11)	0.0040 (11)
C4	0.0292 (14)	0.0235 (14)	0.0348 (15)	0.0034 (11)	−0.0048 (12)	0.0022 (11)
C5	0.0254 (14)	0.0226 (14)	0.0320 (14)	0.0048 (11)	0.0015 (12)	0.0039 (11)
C6	0.0274 (14)	0.0254 (15)	0.0299 (14)	0.0045 (11)	0.0015 (12)	0.0037 (11)
C7	0.0262 (14)	0.0255 (14)	0.0342 (15)	0.0040 (11)	−0.0034 (12)	0.0030 (11)
O1	0.0474 (14)	0.0269 (12)	0.0514 (14)	0.0090 (9)	−0.0156 (11)	−0.0022 (9)
C8	0.062 (2)	0.0276 (17)	0.070 (2)	0.0148 (15)	−0.025 (2)	−0.0001 (16)
O2	0.0405 (12)	0.0287 (12)	0.0423 (12)	0.0116 (9)	−0.0126 (10)	0.0013 (9)
C9	0.0418 (18)	0.0317 (17)	0.0392 (16)	0.0025 (13)	−0.0133 (14)	−0.0007 (13)
O3	0.0377 (12)	0.0289 (11)	0.0356 (11)	0.0049 (8)	−0.0145 (9)	−0.0002 (8)

Geometric parameters (Å, º) top

C1—C2	1.382 (4)	C6—C7	1.474 (4)
C1—C6	1.404 (4)	C7—O1	1.236 (3)
C1—H1	0.94	C7—C5ⁱ	1.479 (4)
C2—O2	1.359 (3)	C8—O2	1.428 (4)
C2—C3	1.414 (4)	C8—H8A	0.97
C3—O3	1.356 (3)	C8—H8B	0.97
C3—C4	1.379 (4)	C8—H8C	0.97
C4—C5	1.397 (4)	C9—O3	1.434 (3)
C4—H4	0.94	C9—H9A	0.97
C5—C6	1.392 (4)	C9—H9B	0.97
C5—C7ⁱ	1.479 (4)	C9—H9C	0.97

C2—C1—C6	120.2 (3)	O1—C7—C6	121.0 (2)
C2—C1—H1	119.9	O1—C7—C5ⁱ	120.7 (2)
C6—C1—H1	119.9	C6—C7—C5ⁱ	118.3 (2)
O2—C2—C1	125.2 (3)	O2—C8—H8A	109.5
O2—C2—C3	114.9 (2)	O2—C8—H8B	109.5
C1—C2—C3	119.9 (2)	H8A—C8—H8B	109.5
O3—C3—C4	125.5 (3)	O2—C8—H8C	109.5
O3—C3—C2	114.8 (2)	H8A—C8—H8C	109.5
C4—C3—C2	119.7 (2)	H8B—C8—H8C	109.5
C3—C4—C5	120.5 (3)	C2—O2—C8	117.2 (2)
C3—C4—H4	119.7	O3—C9—H9A	109.5
C5—C4—H4	119.7	O3—C9—H9B	109.5
C6—C5—C4	119.9 (3)	H9A—C9—H9B	109.5
C6—C5—C7ⁱ	120.8 (2)	O3—C9—H9C	109.5
C4—C5—C7ⁱ	119.3 (2)	H9A—C9—H9C	109.5
C5—C6—C1	119.7 (3)	H9B—C9—H9C	109.5
C5—C6—C7	120.9 (2)	C3—O3—C9	117.4 (2)
C1—C6—C7	119.3 (3)

C6—C1—C2—O2	179.8 (3)	C4—C5—C6—C7	−179.1 (3)
C6—C1—C2—C3	0.0 (4)	C7ⁱ—C5—C6—C7	0.6 (5)
O2—C2—C3—O3	0.2 (4)	C2—C1—C6—C5	−0.1 (4)
C1—C2—C3—O3	−180.0 (3)	C2—C1—C6—C7	179.0 (3)
O2—C2—C3—C4	−179.5 (3)	C5—C6—C7—O1	178.8 (3)
C1—C2—C3—C4	0.3 (4)	C1—C6—C7—O1	−0.3 (4)
O3—C3—C4—C5	179.9 (3)	C5—C6—C7—C5ⁱ	−0.6 (5)
C2—C3—C4—C5	−0.4 (4)	C1—C6—C7—C5ⁱ	−179.7 (3)
C3—C4—C5—C6	0.3 (4)	C1—C2—O2—C8	4.9 (5)
C3—C4—C5—C7ⁱ	−179.4 (3)	C3—C2—O2—C8	−175.3 (3)
C4—C5—C6—C1	0.0 (4)	C4—C3—O3—C9	−2.1 (4)
C7ⁱ—C5—C6—C1	179.7 (3)	C2—C3—O3—C9	178.2 (3)

Symmetry code: (i) −x, −y+1, −z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8A···O1ⁱⁱ	0.97	2.58	3.391 (5)	142
C9—H9B···O2ⁱⁱⁱ	0.97	2.54	3.494 (4)	168

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

Experimental details

Crystal data
Chemical formula	C₁₈H₁₆O₆
M_r	328.31
Crystal system, space group	Triclinic, P1
Temperature (K)	223
a, b, c (Å)	4.6607 (4), 8.4769 (9), 9.8110 (9)
α, β, γ (°)	94.859 (3), 91.410 (2), 97.278 (2)
V (Å³)	382.87 (6)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	0.11
Crystal size (mm)	0.50 × 0.06 × 0.05

Data collection
Diffractometer	Rigaku R-AXIS RAPID
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	3738, 1725, 977
R_int	0.027
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.054, 0.234, 1.16
No. of reflections	1725
No. of parameters	111
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.39, −0.44

Computer programs: RAPID-AUTO (Rigaku, 1999), PROCESS-AUTO (Rigaku, 1998), SIR2004 (Burla et al., 2005), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8A···O1ⁱ	0.97	2.58	3.391 (5)	142
C9—H9B···O2ⁱⁱ	0.97	2.54	3.494 (4)	168

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

Acknowledgements

This work was partly supported by a Grant-in-Aid for Scientific Research (C) (No. 23550161) from JSPS and a Grant-in-Aid for Scientific Research on Innovative Areas (No. 23108720, "pi-Space") from MEXT.

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