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Acta Crystallogr Sect E Struct Rep Online. 2008 October 1; 64(Pt 10): o1869.
Published online 2008 September 6. doi:  10.1107/S1600536808027542
PMCID: PMC2959375

2,6-Dimethyl-4-m-tolyl­cyclo­hex-3-enecarboxylic acid

Abstract

The title compound, C16H20O2, was synthesized to study the hydrogen-bonding inter­action of the two enanti­omers in the solid state. The racemate is made up of carboxylic acid RS dimers. Inter­molecular O—H(...)O hydrogen bonds produce centrosymmetric R 2 2(8) rings which dimerize the two chiral enanti­omers through their carboxyl groups. The chirality of this compound is generated by the presence of the double bond in the cyclo­hexene ring and a chiral axis due to the meta-methyl substituent on the aromatic ring.

Related literature

In similar compounds previously reported (Xie et al., 2002 [triangle], 2007a [triangle], 2008 [triangle]), the racemates also consist of carboxylic acid RS dimers. For related literature, see: Xie et al. (2007b [triangle], 2004 [triangle]); Bernstein et al. (1995 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-o1869-scheme1.jpg

Experimental

Crystal data

  • C16H20O2
  • M r = 244.32
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-64-o1869-efi1.jpg
  • a = 11.2581 (10) Å
  • b = 8.1055 (7) Å
  • c = 29.857 (3) Å
  • V = 2724.5 (4) Å3
  • Z = 8
  • Mo Kα radiation
  • μ = 0.08 mm−1
  • T = 150 (2) K
  • 0.20 × 0.18 × 0.05 mm

Data collection

  • Bruker Kappa APEXII diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.985, T max = 0.996
  • 18515 measured reflections
  • 3120 independent reflections
  • 2265 reflections with I > 2σ(I)
  • R int = 0.043

Refinement

  • R[F 2 > 2σ(F 2)] = 0.049
  • wR(F 2) = 0.136
  • S = 1.03
  • 3120 reflections
  • 170 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.50 e Å−3
  • Δρmin = −0.20 e Å−3

Data collection: APEX2 (Bruker, 2007 [triangle]); cell refinement: SAINT (Bruker, 2007 [triangle]); data reduction: SAINT; program(s) used to solve structure: SIR2004 (Burla et al., 2005 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808027542/om2254sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808027542/om2254Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

SX and HS are grateful to the departmental fund and the Grant-in-aid for Faculty Research from Indiana University Kokomo, as well as a Senior Research Grant from Indiana Academy of Science.

supplementary crystallographic information

Comment

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 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, 2008). 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 all near 180°, as are those involving atoms C13, C2, C3, C4, and C15. The carboxyl group is almost perpendicular to the cyclohexene ring with an angle of 86.5° between the O1—C14—O2 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 42.4°. Unlike other previously reported para substituted analogs, the molecule also has a chiral axis due to the meta methyl substituent on the aromatic ring.

Fig. 2 shows the hydrogen bonding scheme. Atom O1 acts as a donor in an intermolecular hydrogen bond to atom O2, 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.

Experimental

The title carboxylic acid was synthesized following the similar method reported by Xie et al., 2002. The purified compound was recrystallized from hexane-dichloromethane as colorless plates (m.p. 412–415 K).

Refinement

The hydrogen atoms not involved in hydrogen bonding were placed in idealized positions and refined as riding atoms with relative isotropic displacement parameters; they were positioned geometrically and refined using a riding model with C—H = 0.95 Å and Uiso(H) = 1.2 times Ueq(C). H1O was refined freely with individual displacement parameters.

Figures

Fig. 1.
The molecular structure and atom numbering scheme.
Fig. 2.
Hydrogen bonded dimer. Dashed lines represent hydrogen bonds. [Symmetry code: #1 -x + 1, -y, -z + 1.]

Crystal data

C16H20O2F(000) = 1056
Mr = 244.32Dx = 1.191 Mg m3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2abCell parameters from 3951 reflections
a = 11.2581 (10) Åθ = 3.2–25.9°
b = 8.1055 (7) ŵ = 0.08 mm1
c = 29.857 (3) ÅT = 150 K
V = 2724.5 (4) Å3Plate, colorless
Z = 80.20 × 0.18 × 0.05 mm

Data collection

Bruker Kappa APEXII diffractometer3120 independent reflections
Radiation source: fine-focus sealed tube2265 reflections with I > 2σ(I)
graphiteRint = 0.043
Detector resolution: 8.3 pixels mm-1θmax = 27.5°, θmin = 1.4°
ω and [var phi] scansh = −14→12
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)k = −10→10
Tmin = 0.985, Tmax = 0.996l = −38→36
18515 measured reflections

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.049Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.136H atoms treated by a mixture of independent and constrained refinement
S = 1.03w = 1/[σ2(Fo2) + (0.066P)2 + 0.9686P] where P = (Fo2 + 2Fc2)/3
3120 reflections(Δ/σ)max < 0.001
170 parametersΔρmax = 0.50 e Å3
0 restraintsΔρmin = −0.20 e Å3

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)

xyzUiso*/Ueq
O10.47404 (12)0.21830 (16)0.50798 (4)0.0403 (3)
H1O0.477 (3)0.103 (4)0.5238 (11)0.113 (11)*
O20.51225 (11)0.06571 (15)0.44750 (4)0.0362 (3)
C10.56818 (15)0.5618 (2)0.38758 (6)0.0333 (4)
H1A0.57230.65040.41040.040*
H1B0.63390.57990.36610.040*
C20.58687 (14)0.3953 (2)0.41086 (6)0.0308 (4)
H20.59780.30870.38730.037*
C30.47402 (14)0.3553 (2)0.43738 (5)0.0274 (4)
H30.45780.44940.45820.033*
C40.36497 (13)0.3349 (2)0.40608 (5)0.0272 (3)
H40.37110.22620.39040.033*
C50.36254 (14)0.4705 (2)0.37130 (6)0.0309 (4)
H50.29230.48220.35400.037*
C60.45258 (14)0.57605 (19)0.36300 (5)0.0262 (3)
C70.43895 (13)0.7170 (2)0.33124 (5)0.0282 (4)
C80.37328 (15)0.7010 (2)0.29151 (5)0.0316 (4)
H80.33740.59790.28460.038*
C90.35932 (15)0.8328 (2)0.26180 (6)0.0354 (4)
C100.41173 (16)0.9834 (2)0.27251 (7)0.0413 (5)
H100.40381.07400.25250.050*
C110.47524 (17)1.0027 (2)0.31192 (7)0.0421 (5)
H110.50881.10700.31910.051*
C120.49008 (15)0.8706 (2)0.34103 (6)0.0351 (4)
H120.53510.88430.36770.042*
C130.69806 (14)0.4001 (2)0.43992 (6)0.0360 (4)
H13A0.76620.43360.42160.054*
H13B0.71270.29030.45250.054*
H13C0.68680.47950.46430.054*
C140.48878 (13)0.2002 (2)0.46525 (6)0.0284 (4)
C150.25044 (15)0.3372 (2)0.43369 (6)0.0333 (4)
H15A0.18200.32370.41370.050*
H15B0.24400.44270.44960.050*
H15C0.25200.24680.45550.050*
C160.2881 (2)0.8129 (3)0.21924 (6)0.0483 (5)
H16A0.28770.69650.21030.072*
H16B0.32400.87930.19540.072*
H16C0.20640.85000.22440.072*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0541 (8)0.0364 (7)0.0303 (7)0.0076 (6)0.0021 (6)0.0048 (6)
O20.0399 (6)0.0362 (7)0.0327 (7)0.0045 (5)0.0002 (5)0.0041 (5)
C10.0313 (8)0.0340 (9)0.0346 (9)−0.0030 (7)0.0007 (7)0.0049 (7)
C20.0261 (8)0.0334 (9)0.0330 (9)−0.0012 (6)−0.0007 (7)0.0037 (7)
C30.0260 (7)0.0288 (8)0.0273 (8)0.0012 (6)0.0000 (6)0.0012 (7)
C40.0251 (7)0.0273 (8)0.0292 (8)−0.0019 (6)−0.0039 (6)0.0038 (7)
C50.0287 (8)0.0330 (9)0.0310 (9)0.0013 (6)−0.0041 (7)0.0052 (7)
C60.0298 (7)0.0267 (8)0.0222 (8)0.0020 (6)0.0022 (6)−0.0003 (6)
C70.0275 (7)0.0306 (8)0.0264 (8)0.0031 (6)0.0068 (6)0.0046 (7)
C80.0346 (8)0.0319 (9)0.0282 (8)0.0042 (7)0.0046 (7)0.0032 (7)
C90.0339 (8)0.0419 (10)0.0305 (9)0.0081 (7)0.0059 (7)0.0096 (8)
C100.0366 (9)0.0398 (10)0.0474 (11)0.0026 (8)0.0077 (8)0.0184 (9)
C110.0384 (9)0.0328 (9)0.0551 (12)−0.0057 (8)0.0049 (9)0.0107 (9)
C120.0329 (8)0.0356 (9)0.0368 (9)−0.0041 (7)0.0029 (7)0.0054 (8)
C130.0257 (8)0.0414 (10)0.0410 (10)−0.0020 (7)−0.0027 (7)0.0061 (8)
C140.0199 (7)0.0289 (8)0.0365 (9)0.0000 (6)−0.0029 (6)0.0017 (7)
C150.0293 (8)0.0363 (9)0.0344 (9)0.0007 (7)−0.0020 (7)0.0023 (7)
C160.0602 (12)0.0509 (12)0.0338 (10)0.0090 (10)−0.0029 (9)0.0125 (9)

Geometric parameters (Å, °)

O1—C141.295 (2)C7—C81.404 (2)
O1—H1O1.05 (3)C8—C91.398 (2)
O2—C141.241 (2)C8—H80.9500
C1—C61.499 (2)C9—C101.393 (3)
C1—C21.533 (2)C9—C161.511 (3)
C1—H1A0.9900C10—C111.386 (3)
C1—H1B0.9900C10—H100.9500
C2—C131.524 (2)C11—C121.390 (3)
C2—C31.532 (2)C11—H110.9500
C2—H21.0000C12—H120.9500
C3—C141.517 (2)C13—H13A0.9800
C3—C41.552 (2)C13—H13B0.9800
C3—H31.0000C13—H13C0.9800
C4—C51.512 (2)C15—H15A0.9800
C4—C151.530 (2)C15—H15B0.9800
C4—H41.0000C15—H15C0.9800
C5—C61.349 (2)C16—H16A0.9800
C5—H50.9500C16—H16B0.9800
C6—C71.493 (2)C16—H16C0.9800
C7—C121.402 (2)
C14—O1—H1O109.7 (18)C9—C8—H8119.2
C6—C1—C2114.13 (13)C7—C8—H8119.2
C6—C1—H1A108.7C10—C9—C8118.46 (16)
C2—C1—H1A108.7C10—C9—C16120.77 (16)
C6—C1—H1B108.7C8—C9—C16120.77 (17)
C2—C1—H1B108.7C11—C10—C9120.85 (16)
H1A—C1—H1B107.6C11—C10—H10119.6
C13—C2—C3113.10 (14)C9—C10—H10119.6
C13—C2—C1110.39 (14)C10—C11—C12120.39 (18)
C3—C2—C1107.85 (13)C10—C11—H11119.8
C13—C2—H2108.5C12—C11—H11119.8
C3—C2—H2108.5C11—C12—C7120.30 (17)
C1—C2—H2108.5C11—C12—H12119.9
C14—C3—C2111.58 (13)C7—C12—H12119.9
C14—C3—C4109.18 (13)C2—C13—H13A109.5
C2—C3—C4111.55 (13)C2—C13—H13B109.5
C14—C3—H3108.1H13A—C13—H13B109.5
C2—C3—H3108.1C2—C13—H13C109.5
C4—C3—H3108.1H13A—C13—H13C109.5
C5—C4—C15110.23 (13)H13B—C13—H13C109.5
C5—C4—C3110.51 (13)O2—C14—O1123.21 (15)
C15—C4—C3109.93 (13)O2—C14—C3121.15 (15)
C5—C4—H4108.7O1—C14—C3115.63 (15)
C15—C4—H4108.7C4—C15—H15A109.5
C3—C4—H4108.7C4—C15—H15B109.5
C6—C5—C4124.97 (14)H15A—C15—H15B109.5
C6—C5—H5117.5C4—C15—H15C109.5
C4—C5—H5117.5H15A—C15—H15C109.5
C5—C6—C7121.65 (14)H15B—C15—H15C109.5
C5—C6—C1120.91 (14)C9—C16—H16A109.5
C7—C6—C1117.33 (13)C9—C16—H16B109.5
C12—C7—C8118.32 (15)H16A—C16—H16B109.5
C12—C7—C6120.32 (15)C9—C16—H16C109.5
C8—C7—C6121.34 (15)H16A—C16—H16C109.5
C9—C8—C7121.65 (16)H16B—C16—H16C109.5
C6—C1—C2—C13−172.47 (14)C1—C6—C7—C12−35.8 (2)
C6—C1—C2—C3−48.44 (19)C5—C6—C7—C8−38.1 (2)
C13—C2—C3—C14−52.09 (19)C1—C6—C7—C8145.50 (15)
C1—C2—C3—C14−174.45 (14)C12—C7—C8—C90.7 (2)
C13—C2—C3—C4−174.51 (14)C6—C7—C8—C9179.46 (15)
C1—C2—C3—C463.12 (17)C7—C8—C9—C10−0.4 (2)
C14—C3—C4—C5−168.20 (13)C7—C8—C9—C16−179.91 (16)
C2—C3—C4—C5−44.41 (18)C8—C9—C10—C11−0.7 (3)
C14—C3—C4—C1569.91 (17)C16—C9—C10—C11178.81 (18)
C2—C3—C4—C15−166.30 (13)C9—C10—C11—C121.5 (3)
C15—C4—C5—C6133.15 (17)C10—C11—C12—C7−1.2 (3)
C3—C4—C5—C611.4 (2)C8—C7—C12—C110.1 (2)
C4—C5—C6—C7−173.87 (15)C6—C7—C12—C11−178.63 (15)
C4—C5—C6—C12.4 (3)C2—C3—C14—O2−59.64 (19)
C2—C1—C6—C517.0 (2)C4—C3—C14—O264.14 (18)
C2—C1—C6—C7−166.55 (14)C2—C3—C14—O1121.08 (15)
C5—C6—C7—C12140.62 (17)C4—C3—C14—O1−115.15 (15)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O1—H1O···O2i1.05 (3)1.62 (3)2.6628 (18)174 (3)

Symmetry codes: (i) −x+1, −y, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: OM2254).

References

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