2,4,5 Tri­meth­oxy 1 nitro­benzene: a structure in the rare space group P42

Acta Cryst.(2004). E60, o1031±o1033 DOI: 10.1107/S1600536804011651 Christophe M. L. Vande Veldeet al. C₉H₁₁NO₅

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organic papers

Acta Crystallographica Section E Structure Reports Online

ISSN 1600-5368

2,4,5-Trimethoxy-1-nitrobenzene: a

structure in the rare space group

P

4

Christophe M. L. Vande Velde, Herman J. Geise and Frank Blockhuys*

Structural Chemistry Group, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium

Correspondence e-mail: [email protected]

Key indicators

Single-crystal X-ray study

T= 293 K

Mean(C±C) = 0.003 AÊ

Rfactor = 0.040

wRfactor = 0.118

Data-to-parameter ratio = 11.2

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

#2004 International Union of Crystallography Printed in Great Britain ± all rights reserved

The achiral title compound, C9H11NO5, crystallizes as a chiral

structure in space groupP42. Short contacts between the nitro

group and two methoxy groups on neighbouring molecules can be seen, as can methoxy±methoxy contacts between the other methoxy groups not involved in this interaction.

Comment

2,4,5-Trimethoxy-1-nitrobenzene, (I) (Fig. 1), was synthesized as an intermediate in the route to highly substituted PPV oligomers. It is achiral in solution, but crystallizes as a chiral structure (Flack, 2003) in the tetragonal space groupP42with

four symmetry-equivalent molecules in the unit cell. There is one molecule in the asymmetric unit.

The solid-state structure of (I) is quite remarkable since only 30 compounds in the Cambridge Structural Database (CSD, Version 1.6 with April 2004 update; Allen, 2002) crys-tallize in space group P42 and, of those, only two are

non-organometallic compounds without chiral centres, namely refcodes HYDTML (Liminga & Sùrensen, 1967) and OKAHUD (Eatonet al., 2003).

The distances and angles in this molecule conform to the expected values within experimental error. Note that the lengthening of the C4ÐC5 bond and the associated shortening of C3ÐC4 and C5ÐC6 are due to the lone-pair repulsion of the methoxy O atoms. Indeed, all the methoxy groups lie within 5_{of the mean plane of the molecule (see Table 1). The}

Received 4 May 2004 Accepted 12 May 2004 Online 22 May 2004

Figure 1

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angle between the least-squares planes of the nitro group and the benzene ring is 12.9 (2)_{. These out-of-plane torsions of}

the substituents introduce the chirality in the molecule. The reason for the existence of this torsion and the particular packing can be found in the interactions that exist in the crystal structure. The majority of the contacts shorter than the sum of the van der Waals radii are between nitro and methoxy groups. A nitro group, and in particular atom O5, contacts the 2- and 4-methoxy groups of neighbouring molecules (see Table 2, and Fig. 2 for a view of the structure and these interactions). Atom O6 also contacts a number of methoxy groups, but the distances for these contacts are longer than the van der Waals cut-off criterion. In the CSD, we found only 97 structures which display these kinds of phenyl± methoxy nitro±phenyl contacts with a distance shorter than the sum of the van der Waals radii, and an NÐO H angle between 180 and 90_.

Even though these appear to be relatively rare features, in the present case it is clear that they are very important in the construction of the crystal structure, as hardly any other interactions are available to determine the stacking. The exception to this is the methoxy±methoxy contact between the 5-methoxy group designated by C9 O4(y, 1ÿx, zÿ1

2) =

3.204 (3) AÊ and OÐC9 O4(y, 1ÿx, zÿ1

2) = 161.95 (18),

which results in a double helix of interacting 5-methoxy groups around the fourfold screw axis; this can be seen clearly in Fig. 2. Another possible factor stabilizing the stacks of rings in the crystal structure is the parallel-displaced± interac-tion evident between the benzene rings, with a centroid-to-centroid distance equal to the length of thecaxis [3.900 (2) AÊ] and a perpendicular centroid-to-plane distance of 3.65 (6) AÊ. Thus we have stacks of benzene rings around the screw tetrad, which are stabilizedviaa double helix of methoxy interactions on one side andviaweak hydrogen bonds between methoxy and nitro groups on the other. These last two types of inter-actions appear to force the structure into the unusual space group in which it crystallizes.

Experimental

Compound (I) was synthesized by slowly adding fuming nitric acid (6 g, 0.036 mol) to 1,2,4-trimethoxybenzene (2.3 g, 0.036 mol) in CH2Cl2 solution (50 ml) at 273 K and, after warming to room

temperature, distilling off the solvent under vacuum and recrys-tallizing the brown compound from ethanol; the yield was 77% (5.9 g, 0.028 mol) of yellow±green crystals of (I). Crystals suitable for X-ray diffraction were grown by slow evaporation of a saturated solution in 1:1 hexane±CH2Cl2.1H NMR (in p.p.m., 400 MHz, CDCl3): 7.58 (s,

1H, H6), 7.26 (s, 1H, H3), 3.98 (s, 3H, 4-OCH3), 3.98 (s, 3H, 5-OCH3),

3.90 (s, 3H, 2-OCH3),13C NMR (in p.p.m., 400 MHz, CDCl3) 154.85

(C4), 150.36 (C2), 142.56 (C5), 131.15 (C1), 109.20 (C6), 97.96 (C3), 57.32, 56.61, 56.48 (OCH3).

Crystal data

C9H11NO5

Mr= 213.19

Tetragonal,P42

a= 15.749 (9) AÊ c= 3.900 (2) AÊ V= 967.3 (9) AÊ3

Z= 4

Dx= 1.464 Mg mÿ3

MoKradiation Cell parameters from 25

re¯ections = 5.8±16.5 = 0.12 mmÿ1

T= 293 (2) K Prism, yellow±green 0.30.30.2 mm

Data collection

Enraf±Nonius MACH3 diffractometer !/2scans

Absorption correction: none 5058 measured re¯ections 1895 independent re¯ections 1070 re¯ections withI> 2(I) Rint= 0.029

max= 32.0

h=ÿ23!19 k=ÿ23!19 l=ÿ5!0 3 standard re¯ections

frequency: 60 min intensity decay: 1%

Re®nement

Re®nement onF2

R[F2_{> 2(F}2_{)] = 0.040}

wR(F2_{) = 0.118}

S= 1.00 1895 re¯ections 169 parameters

Only coordinates of H atoms re®ned

w= 1/[2_(F

o2) + (0.0635P)2

+ 0.0428P]

whereP= (Fo2+ 2Fc2)/3

(/)max= 0.041

max= 0.16 e AÊÿ3

min=ÿ0.17 e AÊÿ3

Table 1

Selected torsion angles (_).

C7ÐO1ÐC2ÐC1 ÿ176.6 (3)

C9ÐO4ÐC5ÐC4 176.2 (3) C8ÐO3ÐC4ÐC5 175.3 (3)

Table 2

Intermolecular nitro±methoxy contacts (AÊ,_{) in (I).}

Atom 1 Atom 2 (B) Distance Symmetry code NÐO B

O5 C7 3.209 (4) ÿy,x,zÿ1

2 114.2 (3)

O5 H7C 2.45 (3) ÿy,x,zÿ1

2 125.8 (11)

O5 H7A 2.64 (4) ÿy,x,z+1

2 157.6 (7)

O5 H8C 2.52 (3) ÿy,x,z+1

2 102.6 (8)

H atoms were located in a difference map and their coordinates were re®ned [CÐH = 0.94 (3)±1.05 (4) AÊ]. TheUiso(H) values were

®xed at 1.2Ueq(Caromatic) and 1.5Ueq(Cmethyl). In the absence of

signi®cant anomalous scattering, Friedel pairs were merged.

Figure 2

A view of the cell of (I), showing the methoxy double helix around the 42

Data collection: CAD-4 EXPRESS (Enraf±Nonius, 1994); cell re®nement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to re®ne structure:SHELXL97 (Sheldrick, 1997); molecular graphics:ORTEP-3for Windows(Farrugia, 1997); software used to prepare material for publication:WinGX(Farrugia, 1999).

CVV thanks the Fund for Scienti®c Research (FWO Vlaanderen) for a grant as a research assistant. The authors also thank Professor R. Dommisse and J. Aerts for recording the NMR spectra.

References

Allen, F. H. (2002).Acta Cryst.B58, 380±388.

Eaton, P. E., Zhang, M.-X., Komiya, N., Yang, C.-G., Steele, I. & Gilardi, R. (2003).Synlett, p. 1275.

Enraf±Nonius (1994).CAD-4EXPRESS. Enraf±Nonius, Delft, The Nether-lands.

Farrugia, L. J. (1997).J. Appl. Cryst.30, 565. Farrugia, L. J. (1999).J. Appl. Cryst.32, 837±838. Flack, H. D. (2003).Helv. Chim. Acta,86, 905±921. Harms, K. (1996).XCAD4. University of Marburg, Germany.

Liminga, R. & Sùrensen, A. M. (1967).Acta Chem. Scand.21, 2669±2678. Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. Release 97.2.

University of GoÈttingen, Germany.

Acta Cryst.(2004). E60, o1031±o1033 Christophe M. L. Vande Veldeet al. C₉H₁₁NO₅

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Acta Cryst. (2004). E60, o1031–o1033

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Acta Cryst. (2004). E60, o1031–o1033 [https://doi.org/10.1107/S1600536804011651]

2,4,5-Trimethoxy-1-nitrobenzene: a structure in the rare space group

P

4

Christophe M. L. Vande Velde, Herman J. Geise and Frank Blockhuys

2,4,5-trimethoxy-1-nitrobenzene

Crystal data

C9H11NO5 Mr = 213.19 Tetragonal, P42

Hall symbol: P 4c

a = 15.749 (9) Å

c = 3.900 (2) Å

V = 967.3 (9) Å3 Z = 4

F(000) = 448

Dx = 1.464 Mg m−3

Mo Kα radiation, λ = 0.71073 Å Cell parameters from 25 reflections

θ = 5.8–16.5°

µ = 0.12 mm−1 T = 293 K

Prism, yellow-green 0.3 × 0.3 × 0.2 mm

Data collection

Enraf–Nonius MACH3 diffractometer

Radiation source: fine-focus sealed tube Graphite monochromator

ω/2θ scans

5058 measured reflections 1895 independent reflections 1070 reflections with I > 2σ(I)

Rint = 0.029

θmax = 32.0°, θmin = 1.3° h = −23→19

k = −23→19

l = −5→0

3 standard reflections every 60 min intensity decay: 1%

Refinement

Refinement on F2

Least-squares matrix: full

R[F2 _{> 2σ(F}2_{)] = 0.040} wR(F2_{) = 0.118} S = 1.00 1895 reflections 169 parameters 1 restraint

Primary atom site location: structure-invariant direct methods

Secondary atom site location: difference Fourier map

Hydrogen site location: inferred from neighbouring sites

Only H-atom coordinates refined

w = 1/[σ2_(F

o2) + (0.0635P)2 + 0.0428P]

where P = (Fo2 + 2Fc2)/3

(Δ/σ)max = 0.041

Δρmax = 0.16 e Å−3

Δρmin = −0.17 e Å−3

Special details

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Acta Cryst. (2004). E60, o1031–o1033

Refinement. Refinement of F2 _{against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F}2_,

conventional R-factors R are based on F, with F set to zero for negative F2_{. The threshold expression of F}2 _{> σ(F}2_{) 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

O4 0.37385 (9) 0.36342 (9) 0.0676 (6) 0.0536 (5) O3 0.40971 (9) 0.20815 (9) 0.2237 (7) 0.0526 (5) O1 0.11847 (10) 0.15313 (9) 0.5403 (6) 0.0567 (6) C1 0.16345 (12) 0.28879 (12) 0.3483 (6) 0.0393 (5) N1 0.07951 (11) 0.32485 (12) 0.3891 (8) 0.0520 (6) C2 0.18201 (12) 0.20482 (13) 0.4324 (7) 0.0418 (5) C5 0.30810 (12) 0.31550 (12) 0.1837 (7) 0.0399 (5) C7 0.13922 (18) 0.06909 (15) 0.6428 (10) 0.0557 (7) H7A 0.169 (2) 0.0376 (19) 0.456 (13) 0.084* H7B 0.0879 (19) 0.0444 (19) 0.713 (13) 0.084* H7C 0.177 (2) 0.069 (2) 0.838 (12) 0.084* C3 0.26559 (13) 0.17736 (13) 0.3936 (8) 0.0430 (6) H3 0.2795 (14) 0.1212 (14) 0.452 (9) 0.052* C4 0.32791 (12) 0.23069 (13) 0.2712 (7) 0.0413 (6) O5 0.02629 (12) 0.28761 (11) 0.5549 (10) 0.0944 (10) O6 0.06519 (11) 0.39379 (13) 0.2601 (10) 0.0896 (10) C9 0.35461 (16) 0.44731 (14) −0.0422 (9) 0.0523 (7) H9A 0.3096 (18) 0.4498 (19) −0.229 (12) 0.078* H9B 0.4082 (18) 0.4686 (18) −0.119 (11) 0.078* H9C 0.3319 (19) 0.482 (2) 0.151 (11) 0.078* C8 0.43519 (17) 0.12489 (17) 0.3327 (11) 0.0587 (8) H8A 0.423 (2) 0.117 (2) 0.582 (12) 0.088* H8B 0.4971 (19) 0.1227 (19) 0.268 (11) 0.088* H8C 0.403 (2) 0.080 (2) 0.186 (12) 0.088* C6 0.22654 (13) 0.34291 (13) 0.2232 (8) 0.0413 (5) H6 0.2113 (14) 0.3998 (14) 0.165 (9) 0.050*

Atomic displacement parameters (Å2₎

U11 _U22 _U33 _U12 _U13 _U23

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O5 0.0590 (10) 0.0588 (10) 0.165 (3) −0.0013 (8) 0.0528 (16) 0.0037 (15) O6 0.0546 (10) 0.0748 (12) 0.139 (3) 0.0196 (9) 0.0140 (15) 0.0343 (17) C9 0.0538 (13) 0.0416 (11) 0.0615 (19) −0.0060 (10) 0.0040 (14) 0.0071 (13) C8 0.0479 (12) 0.0489 (13) 0.079 (2) 0.0081 (10) −0.0057 (15) 0.0049 (15) C6 0.0421 (10) 0.0353 (9) 0.0464 (15) −0.0016 (8) −0.0030 (11) 0.0015 (11)

Geometric parameters (Å, º)

O4—C5 1.359 (3) C5—C4 1.413 (3)

O4—C9 1.421 (3) C7—H7A 1.00 (4)

O3—C4 1.349 (2) C7—H7B 0.94 (3)

O3—C8 1.436 (3) C7—H7C 0.96 (4)

O1—C2 1.357 (3) C3—C4 1.377 (3)

O1—C7 1.421 (3) C3—H3 0.94 (2)

C1—C2 1.393 (3) C9—H9A 1.02 (4)

C1—C6 1.397 (3) C9—H9B 0.96 (3)

C1—N1 1.447 (3) C9—H9C 1.00 (4)

N1—O5 1.210 (3) C8—H8A 1.00 (5)

N1—O6 1.218 (3) C8—H8B 1.01 (3)

C2—C3 1.394 (3) C8—H8C 1.05 (4)

C5—C6 1.364 (3) C6—H6 0.95 (2)

C5—O4—C9 117.01 (16) C4—C3—C2 121.4 (2) C4—O3—C8 117.81 (19) C4—C3—H3 119.5 (14) C2—O1—C7 118.46 (18) C2—C3—H3 119.1 (14) C2—C1—C6 120.80 (18) O3—C4—C3 124.58 (19) C2—C1—N1 122.55 (18) O3—C4—C5 115.24 (18) C6—C1—N1 116.64 (18) C3—C4—C5 120.18 (18) O5—N1—O6 121.6 (2) O4—C9—H9A 113.6 (17) O5—N1—C1 120.1 (2) O4—C9—H9B 103.5 (18) O6—N1—C1 118.3 (2) H9A—C9—H9B 112 (3) O1—C2—C3 122.96 (19) O4—C9—H9C 111 (2) O1—C2—C1 119.18 (17) H9A—C9—H9C 106 (2) C3—C2—C1 117.85 (18) H9B—C9—H9C 111 (3) O4—C5—C6 125.41 (18) O3—C8—H8A 110 (2) O4—C5—C4 115.92 (17) O3—C8—H8B 103.1 (18) C6—C5—C4 118.67 (19) H8A—C8—H8B 116 (3) O1—C7—H7A 111 (2) O3—C8—H8C 108.6 (19) O1—C7—H7B 105.7 (19) H8A—C8—H8C 111 (3) H7A—C7—H7B 114 (3) H8B—C8—H8C 108 (3) O1—C7—H7C 111.7 (19) C5—C6—C1 121.07 (19) H7A—C7—H7C 107 (3) C5—C6—H6 120.4 (14) H7B—C7—H7C 107 (4) C1—C6—H6 118.5 (15)

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