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Acta Cryst.(2002). E58, o1145±o1146 DOI: 10.1107/S1600536802016975 J. W. Springeret al. C18H18O4

o1145

organic papers

Acta Crystallographica Section E Structure Reports Online

ISSN 1600-5368

1,4,5,8-Tetramethoxyanthracene

J. W. Springer, T. A. Moore, A. L. Moore, Devens Gust* and Thomas L. Groy

Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA

Correspondence e-mail: gust@asu.edu

Key indicators

Single-crystal X-ray study

T= 298 K

Mean(C±C) = 0.002 AÊ

Rfactor = 0.052

wRfactor = 0.140

Data-to-parameter ratio = 17.0

For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.

#2002 International Union of Crystallography Printed in Great Britain ± all rights reserved

The structure of the title compound, C18H18O4, consists of separate centrosymmetric planar molecules arranged in columns parallel to the monoclinic unique axis. The normal to the mean molecular plane lies at 55.4to the unique axis, giving adjacent columns with alternating stacking directions. The mean deviation of all non-H atoms from the least-squares molecular plane is 0.064 AÊ. Bond lengths in the aromatic rings range from 1.347 (2) to 1.440 (2) AÊ and the two unique MeÐ O bond distances are 1.418 (2) and 1.419 (2) AÊ.

Comment

There has been considerable ongoing research involving the electrochemistry of compounds incorporating multiple quinones. Some of these compounds are anthracene deriva-tives (Joze®aket al., 1989), while others are based on tripty-cene architecture (Doerneret al., 1998; Joze®ak et al., 1989; Quast & Fuchsbauer, 1986; Russell & Suleman, 1981). 1,4,5,8-Tetramethoxyanthracene (1,4,5,8-TMA), (I), has been used as an intermediate in the syntheses of some of these compounds. During research involving the synthesis of molecules that can undergo photoinduced electron transfer, 1,4,5,8-TMA was used as a synthetic intermediate.

The structure of (I) consists of individual molecules having no unusually short intermolecular contacts. The packing is in columns parallel to the b axis. Each molecule is planar, as shown in Fig. 1, with an average deviation from the least-squares plane through all non-H atoms of 0.064 AÊ, and a maximum of 0.164 AÊ by the methyl atom C30. The molecule is slightly distorted, since aromatic ring angles deviate from 120, ranging from 118.44 (13) at C2ÐC7ÐC6 to 122.27 (14) at C1ÐC7ÐC6. Perhaps the most interesting feature of this structure is the tilt of the methoxy groups. The two indepen-dent methoxy groups bend toward each other down the length of the molecule, with facing OÐCÐC angles of 113.85 (13) and 114.16 (13). Since the nearest intermolecular distances are typical of graphitic lamellar structures, these distortions are most likely due to intramolecular steric interactions between the methyl H atoms and their nearest-neighbor aromatic H atom. This type of distortion is in agreement with gas-phase molecular mechanics (MM2) calculations.

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Experimental

The title compound was prepared from bromo-2,5-dimethoxy-benzene, using a synthesis developed by Fleming & Mah (1975) and re®ned by Fitzgerald et al. (1992). Their method is a one-step synthesis, using 2,2,6,6-tetramethylpiperidine in re¯uxing tetra-hydrofuran, and provides moderate yields.

Crystal data

C18H18O4

Mr= 298.32 Monoclinic,P21=n

a= 11.1715 (9) AÊ

b= 5.9994 (5) AÊ

c= 11.7159 (10) AÊ = 109.961 (2)

V= 738.05 (11) AÊ3

Z= 2

Dx= 1.342 Mg mÿ3 MoKradiation Cell parameters from 2419

re¯ections = 3.1±27.4

= 0.09 mmÿ1

T= 298 (2) K Plate, clear pale yellow 0.410.270.11 mm

Data collection

Bruker SMART APEX diffractometer !scans

Absorption correction: none 6951 measured re¯ections 1696 independent re¯ections

1159 re¯ections withI> 2(I)

Rint= 0.043

max= 27.5

h=ÿ14!14

k=ÿ7!7

l=ÿ15!15

Re®nement

Re®nement onF2

R[F2> 2(F2)] = 0.053

wR(F2) = 0.140

S= 1.01 1696 re¯ections 100 parameters

H-atom parameters constrained

w= 1/[2(F

o2) + (0.0745P)2] whereP= (Fo2+ 2Fc2)/3 (/)max< 0.001

max= 0.20 e AÊÿ3

min=ÿ0.33 e AÊÿ3

H atoms were located in difference Fourier maps, then positioned geometrically and allowed to ride on their respective parent atoms.

Data collection:SMART(Bruker, 2002); cell re®nement:SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Bruker, 1997); program(s) used to re®ne structure:SHELXTL; molecular graphics:SHELXTL; software used to prepare material for publication:SHELXTL.

This work was supported by the US Department of Energy (DE-FG03-93ER14404). The authors express their gratitude to the National Science Foundation for their contribution toward the purchase of the single-crystal instrumentation used in this study through Award #CHE-9808440.

References

Bruker (1997). SHELXTL. Version 5.1. Bruker AXS Inc., Madison, Wisconsin, USA.

Bruker (2002).SMART(Version 5.625) andSAINT(Version 6.28A). Bruker AXS Inc., Madison, Wisconsin, USA.

Doerner, T., Gleiter, R. & Neugebauer, F. A. (1998).Eur. J. Org. Chem.pp. 1615±1623.

Fleming, I. & Mah, T. (1975).J. Chem. Soc. Perkin Trans.1, pp. 964±965. Fitzgerald, J. J., Drysdale, N. E. & Olofson, R. A. (1992).Synth. Commun.22,

1807±1812.

Joze®ak, T. H., AlmloÈf, J. E., Feyereisen, M. W. & Miller, L. L. (1989).J. Am. Chem. Soc.111, 4105±4106.

Quast, H. & Fuchsbauer, H. (1986).Chem. Ber.119, 1016±1038.

Russell, G. A. & Suleman, N. K. (1981).J. Am. Chem. Soc.103, 1561±1563.

Figure 1

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supporting information

sup-1

Acta Cryst. (2002). E58, o1145–o1146

supporting information

Acta Cryst. (2002). E58, o1145–o1146 [doi:10.1107/S1600536802016975]

1,4,5,8-Tetramethoxyanthracene

J. W. Springer, T. A. Moore, A. L. Moore, Devens Gust and Thomas L. Groy

S1. Comment

There has been considerable ongoing research involving the electrochemistry of compounds incorporating multiple

quinones. Some of these compounds are anthracene derivatives (Jozefiak et al., 1989), while others are based on

triptycene architecture (Doerner et al., 1998; Jozefiak et al., 1989; Quast & Fuchsbauer, 1986; Russel & Suleman, 1981).

1,4,5,8-Tetramethoxyanthracene (1,4,5,8-TMA), (I), has been used as an intermediate in the syntheses of some of these

compounds. During research involving the synthesis of molecules that can undergo photoinduced electron transfer,

1,4,5,8-TMA was used as a synthetic intermediate.

The structure of (I) consists of individual molecules having no unusually short intermolecular contacts. The packing is

in columns parallel to the b axis. Each molecule is planar, as shown in Fig. 1, with an average deviation from the

least-squares plane through all non-H atoms of 0.064 Å, and a maximum of 0.164 Å by the methyl atom C3′. The molecule is

slightly distorted, since aromatic-ring angles deviate from 120°, ranging from 118.44 (13)° at C2—C7—C6 to

122.27 (14)° at C1—C7—C6. Perhaps the most interesting feature of this structure is the tilt of the bond angles at the

methoxy groups. Both methoxy groups bend toward each other down the length of the molecule, with facing MeO-φ

angles of 113.85 (13) and 114.16 (13)°. These distortions presumably originate from packing effects in the solid state.

S2. Experimental

The title compound was prepared from bromo-2,5-dimethoxybenzene using a synthesis developed by Fleming & Mah

(1975) and refined by Olofson and co-workers (Fitzgerald et al., 1992). Their method is a one-step synthesis using

2,2,6,6-tetramethylpiperidine in refluxing tetrahydrofuran and provides moderate yields.

S3. Refinement

H atoms were located in the difference Fourier maps, then positioned geometrically and allowed to ride on their

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[image:4.610.128.480.71.432.2]

Figure 1

Displacement ellipsoid plot shown at the 50% probability level, viewed perpendicular to the mean plane [symmetry code:

(i) 2 − x, −y, 1 − z].

1,4,5,8-tetramethoxyanthracene

Crystal data

C18H18O4 Mr = 298.32 Monoclinic, P21/n a = 11.1715 (9) Å

b = 5.9994 (5) Å

c = 11.7159 (10) Å

β = 109.961 (2)°

V = 738.05 (11) Å3 Z = 2

F(000) = 316

Dx = 1.342 Mg m−3

Mo radiation, λ = 0.71073 Å Cell parameters from 2419 reflections

θ = 3.1–27.4°

µ = 0.09 mm−1 T = 298 K

Plate, clear pale yellow 0.41 × 0.27 × 0.11 mm

Data collection

Bruker SMART APEX diffractometer

ω scans

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supporting information

sup-3

Acta Cryst. (2002). E58, o1145–o1146

Rint = 0.043

θmax = 27.5°, θmin = 2.2° h = −14→14

k = −7→7

l = −15→15

Refinement

Refinement on F2 Least-squares matrix: full

R[F2 > 2σ(F2)] = 0.053 wR(F2) = 0.140 S = 1.01 1696 reflections 100 parameters 0 restraints

Primary atom site location: structure-invariant direct methods

Secondary atom site location: difference Fourier map

Hydrogen site location: inferred from neighbouring sites

H-atom parameters constrained

w = 1/[σ2(F

o2) + (0.0745P)2] where P = (Fo2 + 2Fc2)/3 (Δ/σ)max < 0.001

Δρmax = 0.20 e Å−3 Δρmin = −0.33 e Å−3

Special details

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

x y z Uiso*/Ueq

C1 0.93841 (14) −0.0031 (2) 0.58475 (13) 0.0388 (4)

H1A 0.8971 −0.0051 0.6415 0.047*

C2 0.90694 (13) 0.1619 (2) 0.49551 (13) 0.0371 (4)

C3 0.81446 (15) 0.3322 (2) 0.48978 (14) 0.0424 (4)

O3 0.75942 (12) 0.31463 (18) 0.57774 (11) 0.0567 (4)

C3′ 0.6846 (2) 0.4977 (4) 0.5903 (2) 0.0732 (6)

H3′A 0.6511 0.4672 0.6540 0.110*

H3′B 0.6155 0.5204 0.5154 0.110*

H3′C 0.7364 0.6294 0.6100 0.110*

C4 0.78783 (15) 0.4906 (3) 0.40273 (15) 0.0485 (4)

H4A 0.7272 0.5990 0.3994 0.058*

C5 0.85135 (16) 0.4937 (3) 0.31609 (15) 0.0477 (4)

H5A 0.8320 0.6045 0.2571 0.057*

C6 0.93910 (15) 0.3381 (2) 0.31856 (13) 0.0415 (4)

O6 1.00633 (11) 0.32670 (18) 0.24022 (10) 0.0551 (4)

C6′ 0.9926 (2) 0.5070 (3) 0.15832 (18) 0.0722 (6)

H6′A 1.0438 0.4802 0.1086 0.108*

H6′B 1.0197 0.6425 0.2033 0.108*

H6′C 0.9048 0.5203 0.1077 0.108*

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Atomic displacement parameters (Å2)

U11 U22 U33 U12 U13 U23

C1 0.0413 (8) 0.0408 (8) 0.0347 (8) −0.0050 (7) 0.0135 (6) −0.0012 (6)

C2 0.0368 (8) 0.0358 (8) 0.0354 (8) −0.0044 (6) 0.0079 (6) −0.0018 (6)

C3 0.0399 (8) 0.0430 (9) 0.0418 (9) −0.0025 (7) 0.0106 (7) −0.0049 (7)

O3 0.0601 (8) 0.0581 (8) 0.0593 (8) 0.0124 (6) 0.0302 (6) 0.0023 (6)

C3′ 0.0627 (13) 0.0778 (14) 0.0891 (15) 0.0194 (10) 0.0387 (11) −0.0018 (11)

C4 0.0454 (9) 0.0423 (9) 0.0515 (10) 0.0081 (7) 0.0083 (8) 0.0007 (8)

C5 0.0524 (10) 0.0401 (9) 0.0430 (9) 0.0014 (7) 0.0067 (7) 0.0087 (7)

C6 0.0442 (9) 0.0418 (9) 0.0344 (8) −0.0064 (7) 0.0079 (7) 0.0029 (7)

O6 0.0641 (8) 0.0575 (8) 0.0474 (7) 0.0045 (6) 0.0236 (6) 0.0171 (5)

C6′ 0.0966 (16) 0.0706 (12) 0.0534 (11) 0.0009 (11) 0.0307 (11) 0.0245 (10)

C7 0.0376 (8) 0.0360 (8) 0.0324 (7) −0.0062 (6) 0.0060 (6) −0.0012 (6)

Geometric parameters (Å, º)

C1—C7i 1.388 (2) C4—C5 1.423 (2)

C1—C2 1.395 (2) C5—C6 1.347 (2)

C2—C7 1.423 (2) C6—O6 1.3717 (19)

C2—C3 1.438 (2) C6—C7 1.440 (2)

C3—C4 1.351 (2) O6—C6′ 1.4191 (19)

C3—O3 1.3725 (19) C7—C1i 1.388 (2)

O3—C3′ 1.418 (2)

C7i—C1—C2 121.85 (13) C6—C5—C4 120.80 (14)

C1—C2—C7 118.87 (13) C5—C6—O6 125.51 (14)

C1—C2—C3 122.17 (14) C5—C6—C7 120.65 (14)

C7—C2—C3 118.95 (13) O6—C6—C7 113.84 (13)

C4—C3—O3 125.55 (14) C6—O6—C6′ 117.18 (14)

C4—C3—C2 120.31 (15) C1i—C7—C2 119.27 (13)

O3—C3—C2 114.15 (13) C1i—C7—C6 122.27 (14)

C3—O3—C3′ 116.71 (14) C2—C7—C6 118.44 (13)

C3—C4—C5 120.85 (14)

Figure

Figure 1Displacement ellipsoid plot shown at the 50% probability level, viewed perpendicular to the mean plane [symmetry code:

References

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