Issue contents
Download PDF of article
Download CIF
3D view
Navigation
Highlighting
Dictionary of Crystallography reference
IUPAC Gold Book reference
more ...
Download citation
FormatBIBTeX
EndNote
RefMan
Refer
Medline
CIF
SGML
Plain Text
share
Previous article
Next article
Previous article
Issue contents
Download PDF of article
Download CIF
3D view
Navigation
Highlighting
Dictionary of Crystallography reference
IUPAC Gold Book reference
more ...
Download citation
FormatBIBTeX
EndNote
RefMan
Refer
Medline
CIF
SGML
Plain Text
share
Next article

organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 65| Part 4| April 2009| Page o778
doi:10.1107/S1600536809008186

4-(3-Meth­oxy­phen­­oxy)butyric acid

Julia Heilmann-Brohl,a Gérard Jaouena and Michael Bolteb*

aÉcole Nationale Supérieure de Chimie de Paris, Laboratoire Charles Friedel, UMR CNRS 7223, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France, and bInstitut für Anorganische Chemie, J. W. Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
*Correspondence e-mail: bolte@chemie.uni-frankfurt.de

(Received 5 March 2009; accepted 5 March 2009; online 19 March 2009)

In the title compound, C11H14O4, an inter­mediate for the synthesis of a new kind of estrogen receptor modulator, all non-H atoms lie on a common plane (r.m.s. deviation = 0.0472 Å). All C—C bonds in the side chain are in a trans conformation, and the hydroxyl group is also trans to the methyl­ene chain. In the crystal structure, mol­ecules form centrosymmetric dimers showing a head-to-head arrangement which is stabilized by O—H⋯O hydrogen bonds. A weak C—H⋯O contact is also present.

Related literature

For the synthesis of 4-(3-meth­oxy-phen­oxy)-butyric acid, see Tandon et al. (1990[Tandon, V. K., Khanna, J. M., Arand, N. & Chandra, A. (1990). Tetrahedron, 46, 2871-2882.]). For estrogen receptor modulators, see Lloyd et al. (2004[Lloyd, D. G., Hughes, R. B., Zisterer, D. M., Williams, D. C., Fattorusso, C., Catalanotti, B., Campiani, G. & Meegan, M. J. (2004). J. Med. Chem. 47, 5612-5615.]). For a similar carboxylic acid, see: Smith et al. (1989[Smith, G., Shariff, S. M., O'Reilly, E. J. & Kennard, C. H. L. (1989). Polyhedron, 8, 39-43.]).

[Scheme 1]

Experimental

Crystal data

  • C11H14O4

  • Mr = 210.22

  • Monoclinic, P 21 /n

  • a = 9.6509 (6) Å

  • b = 5.3998 (4) Å

  • c = 20.2033 (13) Å

  • β = 90.822 (5)°

  • V = 1052.74 (12) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 173 K

  • 0.32 × 0.27 × 0.25 mm
Data collection

  • Stoe IPDS-II two-circle diffractometer

  • Absorption correction: none

  • 15489 measured reflections

  • 2945 independent reflections

  • 2458 reflections with I > 2σ(I)

  • Rint = 0.057
Refinement

  • R[F2 > 2σ(F2)] = 0.043

  • wR(F2) = 0.120

  • S = 1.07

  • 2945 reflections

  • 142 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.31 e Å−3

  • Δρmin = −0.20 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
O41—H41⋯O42i 0.927 (18) 1.804 (19) 2.7292 (11) 175.5 (16)
C17—H17B⋯O42ii 0.98 2.48 3.2477 (14) 135
Symmetry codes: (i) -x, -y+3, -z+1; (ii) x+1, y-1, z.

Data collection: X-AREA (Stoe & Cie, 2001[Stoe & Cie (2001). X-AREA. Stoe & Cie, Darmstadt, Germany.]); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]) and Mercury (Macrae et al., 2006[Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453-457.]); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809008186/ng2557sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809008186/ng2557Isup2.hkl

checkCIF report


Comment top

4-(3-Methoxyphenoxy)butyric acid is an intermediate for the synthesis of a new kind of estrogen receptor modulators (Lloyd et al., 2004). All non-H atoms of the title compound (Fig. 1) lie in a common plane (r.m.s. deviation 0.0472 Å). All C—C bonds in the side chain are in a trans conformation, and the hydroxyl group is also trans to the methylene chain. In the crystal, the molecules form centrosymmetric dimers showing a head-to-head arrangement which is stabilized by O—H···O hydrogen bonds (Fig. 2). In addition to this classical hydrogen bond, there is weak C—H···O contact (Table 1).

Two comparable structures, 4-(4-chlorophenoxy)butanoic acid and 4-(2,4-dichlorophenoxy)butanoic acid, (Smith et al., 1989) adopt a very similar conformation as the title compound. However, the carboxyl group in these structures is slightly twisted out of the molecular plane. The HO—C(O)—CH2—CH2 torsion angle is 161.6° and 170.1° in 4-(4-chlorophenoxy)butanoic acid and 4-(2,4-dichlorophenoxy)butanoic acid, respectively, whereas this torsion angle amounts to 174.73 (9)° in the title compound.

Related literature top

For the synthesis of 4-(3-methoxy-phenoxy)-butyric acid, see Tandon et al. (1990). For estrogen receptor modulators, see Lloyd et al. (2004). For a similar carboxylic acid, see: Smith et al. (1989).

Experimental top

Synthesis of 4-(3-methoxy-phenoxy)-butyric acid ethyl ester (scheme 2):

Cs3CO3 (9.666 mmol, 3.149 g) was added to a solution of 3-methoxyphenol (8.055 mmol, 1.000 g) in acetone (20 ml) and the mixture was stirred for 5 min at r.t.. Ethyl-4-bromobutyrate (8.055 mmol, 1.571 g) was added and the reaction mixture was heated under reflux for 28 h. After cooling to r.t. the slurry was poured onto H2O/ice/HCl and the aqeous phase was extracted with CH2Cl2 (4 x 25 ml). The combined organic layers were washed with H2O (3 x 25 ml), dried over MgSO4 and the solvent was removed under reduced pressure to yield the crude product as a slightly yellow oil. The crude product was subjected to a column chromatography (eluent 100% CH2Cl2), to obtain the pure product as a slightly yellow oil (1.486 g, 77%). 1H-NMR (CDCl3, 300 MHz): δ = 7.165 (tr, J = 8.1 Hz, 1H, C6H4), 6.519 – 6.447 (m, 3H, C6H4), 4.146 (q, J = 7.2 Hz, 2H, H12), 3.987 (tr, J = 6.2 Hz, 2H, H8), 3.780 (s, 3H, O—CH3), 2.509 (tr, J = 7.2 Hz, 2H H10), 2.145 - 2.055 (m, 2H H9), 1.259 (tr, J = 7.2 Hz, 3H, H13).

Synthesis of 4-(3-methoxy-phenoxy)-butyric acid (scheme 3):

4-(3-methoxy-phenoxy)-butyric acid ethyl ester (2.938 mmol, 0.700 g) is dissolved in acetone (10 ml) and H2O (5 ml) and 1 M NaOH (20 ml) is added. The reaction mixture is stirred at r.t. for 1 h and is then poured into H2O/HCl (50 ml). The aqeous phase is extracted with CH2Cl2 (4 x 25 ml), and the combined organic layers are washed with H2O (2 x 30 ml), dried over MgSO4 and the solvent is evaporated. The crude product is obtained as light yellow oil from which colourless crystals – suitable for X-Ray analysis - start to grow within 30 min. Purification of the crude product is conducted by column chromatography. The by-products are removed by elution with CH2Cl2. The desired product is then eluted with MeOH. After evaporation of MeOH, the pure product is obtained as an off-white crystalline solid (0.352 g, 58%). 1H-NMR (CDCl3, 300 MHz): δ = 7.171 (tr, J = 8.3 Hz, 1H, C6H4), 6.526 - 6.447 (m, 3H, C6H4), 4.010 (tr, J = 6.0 Hz, 2H, H8), 3.787 (s, 3H, O—CH3), 2.592 (tr, J = 7.4 Hz, 2H, H10), 2.174 - 2.073 (m, 2H, H9), n.o. (COOH).

Refinement top

H atoms bonded to C were refined with fixed individual displacement parameters [U(H) = 1.2 Ueq(C) or U(H) = 1.5 Ueq(Cmethyl)] using a riding model with Caromatic—H = 0.95 Å, Cmethyl—H = 0.98 Å, and Cmethylene—H = 0.99 Å. The methyl group was allowed to rotate but not to tip. the hydroxy H atom was freely refined.

Computing details top

Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA (Stoe & Cie, 2001); data reduction: X-AREA (Stoe & Cie, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008) and Mercury (Bruno et al., 2002); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. Perspective view of the title compound with the atom numbering scheme; displacement ellipsoids are at the 50% probability level; H atoms are drawn as small spheres of arbitrary radii.
[Figure 2] Fig. 2. Packing diagram of the title compound with view onto the ac plane. Hydrogen bonds shown as dashed lines.
[Figure 3] Fig. 3. The numbering of the ethyl ester of the title compound.
[Figure 4] Fig. 4. The numbering of the title compound.
4-(3-Methoxyphenoxy)butyric acid top
Crystal data top
C11H14O4F(000) = 448
Mr = 210.22Dx = 1.326 Mg m−3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 15224 reflections
a = 9.6509 (6) Åθ = 3.7–29.5°
b = 5.3998 (4) ŵ = 0.10 mm−1
c = 20.2033 (13) ÅT = 173 K
β = 90.822 (5)°Block, colourless
V = 1052.74 (12) Å30.32 × 0.27 × 0.25 mm
Z = 4
Data collection top
Stoe IPDS-II two-circle
diffractometer		2458 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.057
Graphite monochromatorθmax = 29.6°, θmin = 3.7°
ω scansh = −13→13
15489 measured reflectionsk = −7→7
2945 independent reflectionsl = −28→25
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.043H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.120 w = 1/[σ2(Fo2) + (0.0677P)2 + 0.1161P]
where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max = 0.001
2945 reflectionsΔρmax = 0.31 e Å−3
142 parametersΔρmin = −0.20 e Å−3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.048 (5)
Crystal data top
C11H14O4V = 1052.74 (12) Å3
Mr = 210.22Z = 4
Monoclinic, P21/nMo Kα radiation
a = 9.6509 (6) ŵ = 0.10 mm−1
b = 5.3998 (4) ÅT = 173 K
c = 20.2033 (13) Å0.32 × 0.27 × 0.25 mm
β = 90.822 (5)°
Data collection top
Stoe IPDS-II two-circle
diffractometer		2458 reflections with I > 2σ(I)
15489 measured reflectionsRint = 0.057
2945 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0430 restraints
wR(F2) = 0.120H atoms treated by a mixture of independent and constrained refinement
S = 1.07Δρmax = 0.31 e Å−3
2945 reflectionsΔρmin = −0.20 e Å−3
142 parameters
Special details top

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) top
xyzUiso*/Ueq
O10.32321 (7)0.55314 (15)0.64594 (4)0.03035 (19)
C10.36009 (11)0.72446 (18)0.59488 (5)0.0263 (2)
H1A0.38400.63440.55390.032*
H1B0.44110.82480.60910.032*
C20.23475 (10)0.89015 (19)0.58265 (5)0.0265 (2)
H2A0.21510.98600.62320.032*
H2B0.15270.78660.57210.032*
C30.26116 (11)1.0679 (2)0.52546 (5)0.0286 (2)
H3A0.34911.15720.53430.034*
H3B0.27270.97040.48440.034*
C40.14701 (11)1.25525 (19)0.51430 (5)0.0269 (2)
O410.17803 (9)1.41971 (15)0.46803 (4)0.0342 (2)
H410.1036 (18)1.526 (3)0.4617 (8)0.056 (5)*
O420.03810 (8)1.25686 (16)0.54438 (5)0.0382 (2)
C110.42179 (10)0.38789 (18)0.66811 (5)0.0245 (2)
C120.55358 (10)0.36401 (18)0.64103 (5)0.0253 (2)
H120.58140.46820.60580.030*
C130.64437 (10)0.18317 (18)0.66685 (5)0.0243 (2)
C140.60524 (11)0.02991 (19)0.71884 (5)0.0263 (2)
H140.6668−0.09270.73580.032*
C150.47284 (10)0.06066 (19)0.74563 (5)0.0278 (2)
H150.4454−0.04200.78130.033*
C160.38130 (11)0.23721 (19)0.72120 (5)0.0270 (2)
H160.29230.25620.74010.032*
O130.77149 (8)0.17389 (15)0.63728 (4)0.0316 (2)
C170.86678 (11)−0.0111 (2)0.66159 (5)0.0334 (3)
H17A0.88630.01790.70870.050*
H17B0.9532−0.00140.63690.050*
H17C0.8257−0.17580.65580.050*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0250 (4)0.0310 (4)0.0350 (4)0.0067 (3)0.0021 (3)0.0095 (3)
C10.0255 (5)0.0255 (5)0.0277 (5)0.0032 (4)−0.0012 (4)0.0029 (4)
C20.0262 (5)0.0251 (5)0.0281 (5)0.0052 (4)−0.0032 (4)0.0004 (4)
C30.0290 (5)0.0275 (5)0.0294 (5)0.0056 (4)−0.0011 (4)0.0014 (4)
C40.0291 (5)0.0247 (5)0.0268 (5)0.0022 (4)−0.0036 (4)0.0007 (4)
O410.0362 (4)0.0313 (4)0.0351 (4)0.0080 (3)0.0025 (3)0.0096 (3)
O420.0318 (4)0.0371 (5)0.0458 (5)0.0105 (3)0.0055 (4)0.0148 (4)
C110.0238 (4)0.0231 (4)0.0266 (5)0.0024 (3)−0.0027 (4)0.0014 (4)
C120.0263 (5)0.0255 (5)0.0240 (4)0.0018 (3)−0.0002 (3)0.0035 (3)
C130.0237 (4)0.0257 (4)0.0235 (4)0.0021 (3)−0.0008 (3)−0.0002 (4)
C140.0273 (5)0.0250 (5)0.0265 (5)0.0018 (4)−0.0033 (4)0.0035 (4)
C150.0280 (5)0.0282 (5)0.0273 (5)−0.0025 (4)−0.0011 (4)0.0050 (4)
C160.0245 (5)0.0286 (5)0.0280 (5)−0.0010 (4)0.0002 (4)0.0020 (4)
O130.0266 (4)0.0380 (4)0.0303 (4)0.0100 (3)0.0048 (3)0.0095 (3)
C170.0301 (5)0.0382 (6)0.0319 (5)0.0128 (4)0.0026 (4)0.0059 (4)
Geometric parameters (Å, º) top
O1—C111.3747 (11)C11—C161.4061 (14)
O1—C11.4343 (12)C12—C131.4072 (13)
C1—C21.5219 (13)C12—H120.9500
C1—H1A0.9900C13—O131.3732 (12)
C1—H1B0.9900C13—C141.3935 (14)
C2—C31.5263 (14)C14—C151.4047 (14)
C2—H2A0.9900C14—H140.9500
C2—H2B0.9900C15—C161.3858 (14)
C3—C41.5103 (14)C15—H150.9500
C3—H3A0.9900C16—H160.9500
C3—H3B0.9900O13—C171.4394 (12)
C4—O421.2217 (13)C17—H17A0.9800
C4—O411.3268 (13)C17—H17B0.9800
O41—H410.927 (18)C17—H17C0.9800
C11—C121.3977 (13)
C11—O1—C1118.38 (8)O1—C11—C16115.18 (9)
O1—C1—C2106.92 (8)C12—C11—C16120.64 (9)
O1—C1—H1A110.3C11—C12—C13118.96 (9)
C2—C1—H1A110.3C11—C12—H12120.5
O1—C1—H1B110.3C13—C12—H12120.5
C2—C1—H1B110.3O13—C13—C14124.03 (9)
H1A—C1—H1B108.6O13—C13—C12114.80 (8)
C1—C2—C3110.58 (8)C14—C13—C12121.16 (9)
C1—C2—H2A109.5C13—C14—C15118.56 (9)
C3—C2—H2A109.5C13—C14—H14120.7
C1—C2—H2B109.5C15—C14—H14120.7
C3—C2—H2B109.5C16—C15—C14121.53 (9)
H2A—C2—H2B108.1C16—C15—H15119.2
C4—C3—C2113.88 (9)C14—C15—H15119.2
C4—C3—H3A108.8C15—C16—C11119.14 (9)
C2—C3—H3A108.8C15—C16—H16120.4
C4—C3—H3B108.8C11—C16—H16120.4
C2—C3—H3B108.8C13—O13—C17116.57 (8)
H3A—C3—H3B107.7O13—C17—H17A109.5
O42—C4—O41123.38 (9)O13—C17—H17B109.5
O42—C4—C3124.16 (9)H17A—C17—H17B109.5
O41—C4—C3112.46 (9)O13—C17—H17C109.5
C4—O41—H41109.2 (11)H17A—C17—H17C109.5
O1—C11—C12124.18 (9)H17B—C17—H17C109.5
C11—O1—C1—C2−177.45 (8)C11—C12—C13—C14−0.36 (15)
O1—C1—C2—C3−176.12 (8)O13—C13—C14—C15178.91 (9)
C1—C2—C3—C4−174.52 (9)C12—C13—C14—C15−0.52 (15)
C2—C3—C4—O42−5.13 (16)C13—C14—C15—C160.51 (16)
C2—C3—C4—O41174.73 (9)C14—C15—C16—C110.38 (16)
C1—O1—C11—C12−4.53 (15)O1—C11—C16—C15178.32 (9)
C1—O1—C11—C16175.88 (9)C12—C11—C16—C15−1.28 (15)
O1—C11—C12—C13−178.30 (9)C14—C13—O13—C171.43 (15)
C16—C11—C12—C131.27 (15)C12—C13—O13—C17−179.11 (9)
C11—C12—C13—O13−179.83 (9)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O41—H41···O42i0.927 (18)1.804 (19)2.7292 (11)175.5 (16)
C17—H17B···O42ii0.982.483.2477 (14)135
Symmetry codes: (i) −x, −y+3, −z+1; (ii) x+1, y−1, z.

Experimental details

Crystal data
Chemical formulaC11H14O4
Mr210.22
Crystal system, space groupMonoclinic, P21/n
Temperature (K)173
a, b, c (Å)9.6509 (6), 5.3998 (4), 20.2033 (13)
β (°) 90.822 (5)
V (Å3)1052.74 (12)
Z4
Radiation typeMo Kα
µ (mm−1)0.10
Crystal size (mm)0.32 × 0.27 × 0.25
Data collection
DiffractometerStoe IPDS-II two-circle
diffractometer
Absorption correction–
No. of measured, independent and
observed [I > 2σ(I)] reflections		15489, 2945, 2458
Rint0.057
(sin θ/λ)max (Å−1)0.694
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.043, 0.120, 1.07
No. of reflections2945
No. of parameters142
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.31, −0.20

Computer programs: X-AREA (Stoe & Cie, 2001), SHELXS97 (Sheldrick, 2008), XP in SHELXTL-Plus (Sheldrick, 2008) and Mercury (Bruno et al., 2002), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O41—H41···O42i0.927 (18)1.804 (19)2.7292 (11)175.5 (16)
C17—H17B···O42ii0.982.483.2477 (14)135
Symmetry codes: (i) −x, −y+3, −z+1; (ii) x+1, y−1, z.
 

Acknowledgements

JHB acknowledges a fellowship from the Postdoc Programme of the German Academic Exchange Service (DAAD).

References

First citationLloyd, D. G., Hughes, R. B., Zisterer, D. M., Williams, D. C., Fattorusso, C., Catalanotti, B., Campiani, G. & Meegan, M. J. (2004). J. Med. Chem. 47, 5612–5615.  Web of Science CrossRef PubMed CAS Google Scholar
 First citationMacrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationSmith, G., Shariff, S. M., O'Reilly, E. J. & Kennard, C. H. L. (1989). Polyhedron, 8, 39–43.  CSD CrossRef CAS Web of Science Google Scholar
 First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationStoe & Cie (2001). X-AREA. Stoe & Cie, Darmstadt, Germany.  Google Scholar
 First citationTandon, V. K., Khanna, J. M., Arand, N. & Chandra, A. (1990). Tetrahedron, 46, 2871–2882.  CrossRef CAS Web of Science Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 65| Part 4| April 2009| Page o778
doi:10.1107/S1600536809008186
Follow Acta Cryst. E
Sign up for e-alerts
E-alerts
Follow Acta Cryst. on Twitter
Twitter
Follow us on facebook
Facebook
Sign up for RSS feeds
RSS