organic compounds
rac-4-(2-Methoxyphenyl)-2,6-dimethylcyclohex-3-enecarboxylic acid
aDepartment of Natural, Information, and Mathematical Sciences, Indiana University Kokomo, Kokomo, IN 46904–9003, USA, and bIndiana University Molecular Structure Center, Indiana University, Bloomington, IN 47405–7102, USA
*Correspondence e-mail: soxie@iuk.edu
The title compound, C16H20O3, was synthesized to study the hydrogen-bonding interactions of the two enantiomers in the solid state. Intermolecular O—H⋯O hydrogen bonds produce centrosymmetric R22(8) rings which dimerize the two chiral enantiomers together through their carboxyl groups.
Related literature
In similar compounds previously reported (Xie et al., 2002, 2007a, 2008a,b), the racemates also consist of carboxylic acid RS dimers. For the structure of the precursor, see: Xie et al. (2007b). The of the title compound is solely generated by the presence of the double bond in the cyclohexene ring, see: Xie et al. (2004). For hydrogen-bond motifs, see: Bernstein et al. (1995).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S1600536810019732/om2342sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810019732/om2342Isup2.hkl
The title carboxylic acid was synthesized following asimilar method reported by Xie et al., 2002. Purified compound was recrystallized from hexane- dichloromethane as colorless plates (m.p. 417-418 K).
All non-hydrogen atoms were refined with anisotropic displacement parameters. The hydrogen atoms not involved in hydrogen bonding were placed in ideal positions and refined as riding atoms with relative isotropic displacement parameters. H1 was freely refined.
The title carboxylic acid was prepared to study the interaction of the two enantiomers in the solid state. We have previously reported the structure of its precursor, which is achiral and forms hydrogen-bonded dimers (Xie et al., 2007b). The
of the title compound is solely generated by the presence of the double bond in the cyclohexene ring (Xie et al., 2004). The resultant racemate is made up of carboxylic acid RS dimers (Xie et al., 2002, 2007a, 2008a,b). The structure and atom numbering are shown in Fig. 1, which illustrates the half-chair conformation of the cyclohexene ring. The torsion angles involving atoms C4, C5, C6, C1, and C2 are near 0°. The carboxyl group is almost perpendicular to the cyclohexene ring with an angle of 82.2° between the O1—C14—O2—C3 plane and the C1—C6 ring. The double bond between C5—C6 is not fully conjugated with the aromatic ring as shown by the C1—C6—C5 plane to benzene ring angle of 52.6°. Unlike other previously reported para substituted analogs and like other previously reported meta substituted analogs (Xie et al., 2008b), the molecule also has a chiral axis due to the ortho methoxy substituent on the aromatic ring.Fig. 2 shows the hydrogen bonding scheme. Atom O2 acts as a donor in an intermolecular hydrogen bond to atom O1, producing an R22(8) ring (Bernstein et al., 1995), thus creating a hydrogen- bonded dimer. There is no evidence to suggest that weak directional interactions interconnect the dimers. Hydrogen bond geometry is given in Table 1.
In similar compounds previously reported (Xie et al., 2002, 2007a, 2008a,b), the racemates also consist of carboxylic acid RS dimers. For the structure of the precursor, see: Xie et al. (2007b). The
of the title compound is solely generated by the presence of the double bond in the cyclohexene ring, see: Xie et al. (2004). For hydrogen-bond motifs, see: Bernstein et al. (1995).Data collection: APEX2 (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXL97 (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).C16H20O3 | F(000) = 560 |
Mr = 260.32 | Dx = 1.188 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 4026 reflections |
a = 14.2283 (9) Å | θ = 2.8–26.3° |
b = 7.1202 (5) Å | µ = 0.08 mm−1 |
c = 14.9517 (10) Å | T = 150 K |
β = 106.069 (2)° | Plate, colorless |
V = 1455.55 (17) Å3 | 0.25 × 0.23 × 0.07 mm |
Z = 4 |
Bruker APEXII Kappa Duo diffractometer | 2964 independent reflections |
Radiation source: fine-focus sealed tube | 2296 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.022 |
Detector resolution: 83.33 pixels mm-1 | θmax = 26.4°, θmin = 1.5° |
ω and φ scans | h = −16→17 |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | k = −7→8 |
Tmin = 0.980, Tmax = 0.994 | l = −13→18 |
11165 measured reflections |
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)] = 0.048 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.138 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0653P)2 + 0.6215P] where P = (Fo2 + 2Fc2)/3 |
2964 reflections | (Δ/σ)max = 0.001 |
179 parameters | Δρmax = 0.56 e Å−3 |
0 restraints | Δρmin = −0.34 e Å−3 |
C16H20O3 | V = 1455.55 (17) Å3 |
Mr = 260.32 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 14.2283 (9) Å | µ = 0.08 mm−1 |
b = 7.1202 (5) Å | T = 150 K |
c = 14.9517 (10) Å | 0.25 × 0.23 × 0.07 mm |
β = 106.069 (2)° |
Bruker APEXII Kappa Duo diffractometer | 2964 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 2296 reflections with I > 2σ(I) |
Tmin = 0.980, Tmax = 0.994 | Rint = 0.022 |
11165 measured reflections |
R[F2 > 2σ(F2)] = 0.048 | 0 restraints |
wR(F2) = 0.138 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | Δρmax = 0.56 e Å−3 |
2964 reflections | Δρmin = −0.34 e Å−3 |
179 parameters |
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. |
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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.88885 (9) | 0.4779 (2) | 0.00968 (10) | 0.0602 (5) | |
O2 | 1.02302 (9) | 0.3518 (2) | 0.10376 (10) | 0.0531 (4) | |
H2O | 1.051 (2) | 0.411 (4) | 0.0670 (18) | 0.082 (8)* | |
O3 | 0.55725 (8) | −0.14999 (17) | 0.09567 (7) | 0.0342 (3) | |
C1 | 0.76051 (16) | −0.0149 (3) | 0.11315 (14) | 0.0478 (5) | |
H1A | 0.7060 | −0.0803 | 0.0683 | 0.057* | |
H1B | 0.8079 | −0.1122 | 0.1446 | 0.057* | |
C2 | 0.81042 (14) | 0.1106 (3) | 0.05858 (12) | 0.0418 (5) | |
H2 | 0.7585 | 0.1771 | 0.0100 | 0.050* | |
C3 | 0.87036 (12) | 0.2591 (3) | 0.12493 (12) | 0.0366 (4) | |
H3 | 0.9175 | 0.1927 | 0.1775 | 0.044* | |
C4 | 0.80346 (14) | 0.3809 (3) | 0.16515 (13) | 0.0409 (4) | |
H4 | 0.7610 | 0.4559 | 0.1129 | 0.049* | |
C5 | 0.73751 (16) | 0.2583 (3) | 0.20376 (14) | 0.0479 (5) | |
H5 | 0.7053 | 0.3137 | 0.2450 | 0.057* | |
C6 | 0.72161 (11) | 0.0741 (2) | 0.18303 (11) | 0.0300 (4) | |
C7 | 0.66838 (11) | −0.0451 (2) | 0.23497 (10) | 0.0279 (4) | |
C8 | 0.69907 (12) | −0.0459 (2) | 0.33172 (11) | 0.0322 (4) | |
H8 | 0.7515 | 0.0337 | 0.3629 | 0.039* | |
C9 | 0.65520 (14) | −0.1596 (2) | 0.38384 (11) | 0.0377 (4) | |
H9 | 0.6772 | −0.1570 | 0.4499 | 0.045* | |
C10 | 0.57966 (14) | −0.2762 (3) | 0.33929 (12) | 0.0392 (4) | |
H10 | 0.5501 | −0.3557 | 0.3748 | 0.047* | |
C11 | 0.54636 (13) | −0.2784 (2) | 0.24267 (12) | 0.0343 (4) | |
H11 | 0.4942 | −0.3592 | 0.2122 | 0.041* | |
C12 | 0.58967 (11) | −0.1624 (2) | 0.19099 (11) | 0.0279 (4) | |
C13 | 0.87078 (18) | −0.0056 (4) | 0.00957 (17) | 0.0680 (7) | |
H13A | 0.8984 | 0.0766 | −0.0292 | 0.102* | |
H13B | 0.8290 | −0.1004 | −0.0297 | 0.102* | |
H13C | 0.9239 | −0.0680 | 0.0560 | 0.102* | |
C14 | 0.92794 (13) | 0.3744 (3) | 0.07423 (12) | 0.0409 (5) | |
C15 | 0.86046 (19) | 0.5186 (3) | 0.23835 (16) | 0.0615 (6) | |
H15A | 0.8146 | 0.5943 | 0.2615 | 0.092* | |
H15B | 0.8997 | 0.6013 | 0.2105 | 0.092* | |
H15C | 0.9037 | 0.4488 | 0.2901 | 0.092* | |
C16 | 0.47037 (14) | −0.2506 (3) | 0.05064 (12) | 0.0441 (5) | |
H16A | 0.4516 | −0.2223 | −0.0161 | 0.066* | |
H16B | 0.4175 | −0.2129 | 0.0772 | 0.066* | |
H16C | 0.4822 | −0.3857 | 0.0599 | 0.066* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0321 (7) | 0.0899 (12) | 0.0542 (8) | −0.0105 (7) | 0.0048 (6) | 0.0408 (8) |
O2 | 0.0299 (7) | 0.0756 (11) | 0.0510 (8) | −0.0106 (7) | 0.0066 (6) | 0.0317 (7) |
O3 | 0.0347 (6) | 0.0422 (7) | 0.0275 (6) | −0.0110 (5) | 0.0115 (5) | −0.0011 (5) |
C1 | 0.0570 (12) | 0.0433 (11) | 0.0542 (11) | −0.0197 (9) | 0.0341 (10) | −0.0117 (9) |
C2 | 0.0365 (9) | 0.0554 (12) | 0.0387 (9) | −0.0140 (9) | 0.0190 (8) | −0.0047 (8) |
C3 | 0.0303 (9) | 0.0444 (10) | 0.0336 (8) | −0.0108 (8) | 0.0066 (7) | 0.0099 (7) |
C4 | 0.0461 (11) | 0.0374 (10) | 0.0397 (9) | −0.0125 (8) | 0.0124 (8) | 0.0025 (8) |
C5 | 0.0604 (13) | 0.0390 (11) | 0.0554 (11) | −0.0104 (9) | 0.0346 (10) | −0.0058 (9) |
C6 | 0.0270 (8) | 0.0360 (9) | 0.0285 (8) | −0.0060 (7) | 0.0100 (6) | −0.0011 (7) |
C7 | 0.0277 (8) | 0.0292 (8) | 0.0294 (8) | 0.0019 (7) | 0.0121 (6) | 0.0008 (6) |
C8 | 0.0318 (9) | 0.0335 (9) | 0.0315 (8) | 0.0020 (7) | 0.0091 (7) | −0.0001 (7) |
C9 | 0.0475 (10) | 0.0398 (10) | 0.0274 (8) | 0.0071 (8) | 0.0129 (7) | 0.0056 (7) |
C10 | 0.0515 (11) | 0.0355 (9) | 0.0374 (9) | −0.0013 (8) | 0.0236 (8) | 0.0088 (8) |
C11 | 0.0382 (9) | 0.0314 (9) | 0.0374 (9) | −0.0046 (7) | 0.0173 (7) | 0.0010 (7) |
C12 | 0.0301 (8) | 0.0279 (8) | 0.0291 (8) | 0.0011 (7) | 0.0138 (6) | 0.0007 (6) |
C13 | 0.0605 (14) | 0.0884 (18) | 0.0704 (15) | −0.0219 (13) | 0.0437 (12) | −0.0283 (13) |
C14 | 0.0299 (9) | 0.0529 (11) | 0.0365 (9) | −0.0122 (8) | 0.0036 (7) | 0.0126 (8) |
C15 | 0.0778 (16) | 0.0467 (12) | 0.0576 (13) | −0.0251 (12) | 0.0148 (12) | −0.0074 (10) |
C16 | 0.0473 (11) | 0.0508 (11) | 0.0334 (9) | −0.0185 (9) | 0.0098 (8) | −0.0066 (8) |
O1—C14 | 1.219 (2) | C6—C7 | 1.491 (2) |
O2—C14 | 1.312 (2) | C7—C8 | 1.391 (2) |
O2—H2O | 0.88 (3) | C7—C12 | 1.406 (2) |
O3—C12 | 1.3740 (19) | C8—C9 | 1.386 (2) |
O3—C16 | 1.426 (2) | C8—H8 | 0.9500 |
C1—C6 | 1.456 (2) | C9—C10 | 1.376 (3) |
C1—C2 | 1.513 (2) | C9—H9 | 0.9500 |
C1—H1A | 0.9900 | C10—C11 | 1.390 (2) |
C1—H1B | 0.9900 | C10—H10 | 0.9500 |
C2—C13 | 1.519 (3) | C11—C12 | 1.387 (2) |
C2—C3 | 1.537 (2) | C11—H11 | 0.9500 |
C2—H2 | 1.0000 | C13—H13A | 0.9800 |
C3—C14 | 1.504 (2) | C13—H13B | 0.9800 |
C3—C4 | 1.528 (3) | C13—H13C | 0.9800 |
C3—H3 | 1.0000 | C15—H15A | 0.9800 |
C4—C5 | 1.508 (2) | C15—H15B | 0.9800 |
C4—C15 | 1.525 (3) | C15—H15C | 0.9800 |
C4—H4 | 1.0000 | C16—H16A | 0.9800 |
C5—C6 | 1.352 (3) | C16—H16B | 0.9800 |
C5—H5 | 0.9500 | C16—H16C | 0.9800 |
C14—O2—H2O | 110.0 (18) | C9—C8—H8 | 119.1 |
C12—O3—C16 | 117.10 (12) | C7—C8—H8 | 119.1 |
C6—C1—C2 | 117.26 (16) | C10—C9—C8 | 119.56 (15) |
C6—C1—H1A | 108.0 | C10—C9—H9 | 120.2 |
C2—C1—H1A | 108.0 | C8—C9—H9 | 120.2 |
C6—C1—H1B | 108.0 | C9—C10—C11 | 120.40 (16) |
C2—C1—H1B | 108.0 | C9—C10—H10 | 119.8 |
H1A—C1—H1B | 107.2 | C11—C10—H10 | 119.8 |
C1—C2—C13 | 110.54 (18) | C12—C11—C10 | 119.74 (16) |
C1—C2—C3 | 108.53 (14) | C12—C11—H11 | 120.1 |
C13—C2—C3 | 113.54 (16) | C10—C11—H11 | 120.1 |
C1—C2—H2 | 108.0 | O3—C12—C11 | 122.89 (15) |
C13—C2—H2 | 108.0 | O3—C12—C7 | 116.24 (13) |
C3—C2—H2 | 108.0 | C11—C12—C7 | 120.84 (15) |
C14—C3—C4 | 111.98 (15) | C2—C13—H13A | 109.5 |
C14—C3—C2 | 109.42 (14) | C2—C13—H13B | 109.5 |
C4—C3—C2 | 110.45 (14) | H13A—C13—H13B | 109.5 |
C14—C3—H3 | 108.3 | C2—C13—H13C | 109.5 |
C4—C3—H3 | 108.3 | H13A—C13—H13C | 109.5 |
C2—C3—H3 | 108.3 | H13B—C13—H13C | 109.5 |
C5—C4—C15 | 111.17 (16) | O1—C14—O2 | 122.86 (16) |
C5—C4—C3 | 110.10 (15) | O1—C14—C3 | 122.40 (16) |
C15—C4—C3 | 112.43 (17) | O2—C14—C3 | 114.73 (15) |
C5—C4—H4 | 107.6 | C4—C15—H15A | 109.5 |
C15—C4—H4 | 107.6 | C4—C15—H15B | 109.5 |
C3—C4—H4 | 107.6 | H15A—C15—H15B | 109.5 |
C6—C5—C4 | 123.77 (17) | C4—C15—H15C | 109.5 |
C6—C5—H5 | 118.1 | H15A—C15—H15C | 109.5 |
C4—C5—H5 | 118.1 | H15B—C15—H15C | 109.5 |
C5—C6—C1 | 120.94 (16) | O3—C16—H16A | 109.5 |
C5—C6—C7 | 120.64 (15) | O3—C16—H16B | 109.5 |
C1—C6—C7 | 118.33 (15) | H16A—C16—H16B | 109.5 |
C8—C7—C12 | 117.67 (14) | O3—C16—H16C | 109.5 |
C8—C7—C6 | 119.05 (14) | H16A—C16—H16C | 109.5 |
C12—C7—C6 | 123.25 (14) | H16B—C16—H16C | 109.5 |
C9—C8—C7 | 121.77 (16) | ||
C6—C1—C2—C13 | 164.10 (19) | C1—C6—C7—C12 | −53.0 (2) |
C6—C1—C2—C3 | 39.0 (2) | C12—C7—C8—C9 | 0.9 (2) |
C1—C2—C3—C14 | 174.85 (16) | C6—C7—C8—C9 | −177.28 (15) |
C13—C2—C3—C14 | 51.5 (2) | C7—C8—C9—C10 | 0.4 (3) |
C1—C2—C3—C4 | −61.4 (2) | C8—C9—C10—C11 | −0.9 (3) |
C13—C2—C3—C4 | 175.22 (18) | C9—C10—C11—C12 | 0.0 (3) |
C14—C3—C4—C5 | 172.34 (15) | C16—O3—C12—C11 | 5.2 (2) |
C2—C3—C4—C5 | 50.1 (2) | C16—O3—C12—C7 | −172.68 (15) |
C14—C3—C4—C15 | −63.1 (2) | C10—C11—C12—O3 | −176.46 (16) |
C2—C3—C4—C15 | 174.67 (15) | C10—C11—C12—C7 | 1.4 (2) |
C15—C4—C5—C6 | −141.8 (2) | C8—C7—C12—O3 | 176.16 (14) |
C3—C4—C5—C6 | −16.6 (3) | C6—C7—C12—O3 | −5.7 (2) |
C4—C5—C6—C1 | −6.3 (3) | C8—C7—C12—C11 | −1.8 (2) |
C4—C5—C6—C7 | 170.29 (17) | C6—C7—C12—C11 | 176.29 (15) |
C2—C1—C6—C5 | −5.8 (3) | C4—C3—C14—O1 | −56.8 (3) |
C2—C1—C6—C7 | 177.46 (16) | C2—C3—C14—O1 | 66.0 (3) |
C5—C6—C7—C8 | −51.6 (2) | C4—C3—C14—O2 | 124.50 (18) |
C1—C6—C7—C8 | 125.06 (18) | C2—C3—C14—O2 | −112.68 (19) |
C5—C6—C7—C12 | 130.28 (19) |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2O···O1i | 0.88 (3) | 1.79 (3) | 2.6640 (18) | 177 (3) |
Symmetry code: (i) −x+2, −y+1, −z. |
Experimental details
Crystal data | |
Chemical formula | C16H20O3 |
Mr | 260.32 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 150 |
a, b, c (Å) | 14.2283 (9), 7.1202 (5), 14.9517 (10) |
β (°) | 106.069 (2) |
V (Å3) | 1455.55 (17) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.25 × 0.23 × 0.07 |
Data collection | |
Diffractometer | Bruker APEXII Kappa Duo |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.980, 0.994 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 11165, 2964, 2296 |
Rint | 0.022 |
(sin θ/λ)max (Å−1) | 0.625 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.048, 0.138, 1.04 |
No. of reflections | 2964 |
No. of parameters | 179 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.56, −0.34 |
Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SIR2004 (Burla et al., 2005), SHELXL97 (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2O···O1i | 0.88 (3) | 1.79 (3) | 2.6640 (18) | 177 (3) |
Symmetry code: (i) −x+2, −y+1, −z. |
Acknowledgements
SX, BF, and SD are grateful for the Grant-in-aid for Faculty Research from Indiana University Kokomo, as well as the Senior Research Grant from Indiana Academy of Science.
References
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The title carboxylic acid was prepared to study the interaction of the two enantiomers in the solid state. We have previously reported the structure of its precursor, which is achiral and forms hydrogen-bonded dimers (Xie et al., 2007b). The chirality of the title compound is solely generated by the presence of the double bond in the cyclohexene ring (Xie et al., 2004). The resultant racemate is made up of carboxylic acid RS dimers (Xie et al., 2002, 2007a, 2008a,b). The structure and atom numbering are shown in Fig. 1, which illustrates the half-chair conformation of the cyclohexene ring. The torsion angles involving atoms C4, C5, C6, C1, and C2 are near 0°. The carboxyl group is almost perpendicular to the cyclohexene ring with an angle of 82.2° between the O1—C14—O2—C3 plane and the C1—C6 ring. The double bond between C5—C6 is not fully conjugated with the aromatic ring as shown by the C1—C6—C5 plane to benzene ring angle of 52.6°. Unlike other previously reported para substituted analogs and like other previously reported meta substituted analogs (Xie et al., 2008b), the molecule also has a chiral axis due to the ortho methoxy substituent on the aromatic ring.
Fig. 2 shows the hydrogen bonding scheme. Atom O2 acts as a donor in an intermolecular hydrogen bond to atom O1, producing an R22(8) ring (Bernstein et al., 1995), thus creating a hydrogen- bonded dimer. There is no evidence to suggest that weak directional interactions interconnect the dimers. Hydrogen bond geometry is given in Table 1.