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

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ISSN: 2056-9890

2,6-Di­methyl-4-m-tolyl­cyclo­hex-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

(Received 29 July 2008; accepted 27 August 2008; online 6 September 2008)

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 R22(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[Xie, S., Hou, Y., Meyers, C. Y. & Robinson, P. D. (2002). Acta Cryst. E58, o1460-o1462.], 2007a[Xie, S., Kenny, C. & Robinson, P. D. (2007a). Acta Cryst. E63, o3897.], 2008[Xie, S., O'Hearn, C. R. & Robinson, P. D. (2008). Acta Cryst. E64, o554.]), the racemates also consist of carboxylic acid RS dimers. For related literature, see: Xie et al. (2007b[Xie, S., Kenny, C. & Robinson, P. D. (2007b). Acta Cryst. E63, o1660-o1662.], 2004[Xie, S., Meyers, C. Y. & Robinson, P. D. (2004). Acta Cryst. E60, o1362-o1364.]); Bernstein et al. (1995[Bernstein, J., Davis, R., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]).

[Scheme 1]

Experimental

Crystal data
  • C16H20O2

  • Mr = 244.32

  • Orthorhombic, P b c a

  • 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[Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.]) Tmin = 0.985, Tmax = 0.996

  • 18515 measured reflections

  • 3120 independent reflections

  • 2265 reflections with I > 2σ(I)

  • Rint = 0.043

Refinement
  • R[F2 > 2σ(F2)] = 0.049

  • wR(F2) = 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

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H1O⋯O2i 1.05 (3) 1.62 (3) 2.6628 (18) 174 (3)
Symmetry code: (i) -x+1, -y, -z+1.

Data collection: APEX2 (Bruker, 2007[Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2007[Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SIR2004 (Burla et al., 2005[Burla, M. C., Caliandro, R., Camalli, M., Carrozzini, B., Cascarano, G. L., De Caro, L., Giacovazzo, C., Polidori, G. & Spagna, R. (2005). J. Appl. Cryst. 38, 381-388.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

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.

Related literature top

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

Experimental top

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 top

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.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: 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: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure and atom numbering scheme.
[Figure 2] Fig. 2. Hydrogen bonded dimer. Dashed lines represent hydrogen bonds. [Symmetry code: #1 -x + 1, -y, -z + 1.]
2,6-Dimethyl-4-m-tolylcyclohex-3-enecarboxylic acid top
Crystal data top
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 top
Bruker Kappa APEXII
diffractometer
3120 independent reflections
Radiation source: fine-focus sealed tube2265 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.043
Detector resolution: 8.3 pixels mm-1θmax = 27.5°, θmin = 1.4°
ω and ϕ scansh = 1412
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
k = 1010
Tmin = 0.985, Tmax = 0.996l = 3836
18515 measured reflections
Refinement top
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 = 1.03 w = 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
Crystal data top
C16H20O2V = 2724.5 (4) Å3
Mr = 244.32Z = 8
Orthorhombic, PbcaMo Kα radiation
a = 11.2581 (10) ŵ = 0.08 mm1
b = 8.1055 (7) ÅT = 150 K
c = 29.857 (3) Å0.20 × 0.18 × 0.05 mm
Data collection top
Bruker Kappa APEXII
diffractometer
3120 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
2265 reflections with I > 2σ(I)
Tmin = 0.985, Tmax = 0.996Rint = 0.043
18515 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0490 restraints
wR(F2) = 0.136H atoms treated by a mixture of independent and constrained refinement
S = 1.03Δρmax = 0.50 e Å3
3120 reflectionsΔρmin = 0.20 e Å3
170 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
O10.47404 (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) top
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, º) top
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—C13172.47 (14)C1—C6—C7—C1235.8 (2)
C6—C1—C2—C348.44 (19)C5—C6—C7—C838.1 (2)
C13—C2—C3—C1452.09 (19)C1—C6—C7—C8145.50 (15)
C1—C2—C3—C14174.45 (14)C12—C7—C8—C90.7 (2)
C13—C2—C3—C4174.51 (14)C6—C7—C8—C9179.46 (15)
C1—C2—C3—C463.12 (17)C7—C8—C9—C100.4 (2)
C14—C3—C4—C5168.20 (13)C7—C8—C9—C16179.91 (16)
C2—C3—C4—C544.41 (18)C8—C9—C10—C110.7 (3)
C14—C3—C4—C1569.91 (17)C16—C9—C10—C11178.81 (18)
C2—C3—C4—C15166.30 (13)C9—C10—C11—C121.5 (3)
C15—C4—C5—C6133.15 (17)C10—C11—C12—C71.2 (3)
C3—C4—C5—C611.4 (2)C8—C7—C12—C110.1 (2)
C4—C5—C6—C7173.87 (15)C6—C7—C12—C11178.63 (15)
C4—C5—C6—C12.4 (3)C2—C3—C14—O259.64 (19)
C2—C1—C6—C517.0 (2)C4—C3—C14—O264.14 (18)
C2—C1—C6—C7166.55 (14)C2—C3—C14—O1121.08 (15)
C5—C6—C7—C12140.62 (17)C4—C3—C14—O1115.15 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1O···O2i1.05 (3)1.62 (3)2.6628 (18)174 (3)
Symmetry code: (i) x+1, y, z+1.

Experimental details

Crystal data
Chemical formulaC16H20O2
Mr244.32
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)150
a, b, c (Å)11.2581 (10), 8.1055 (7), 29.857 (3)
V3)2724.5 (4)
Z8
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.20 × 0.18 × 0.05
Data collection
DiffractometerBruker Kappa APEXII
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.985, 0.996
No. of measured, independent and
observed [I > 2σ(I)] reflections
18515, 3120, 2265
Rint0.043
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.136, 1.03
No. of reflections3120
No. of parameters170
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.50, 0.20

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SIR2004 (Burla et al., 2005), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1O···O2i1.05 (3)1.62 (3)2.6628 (18)174 (3)
Symmetry code: (i) x+1, y, z+1.
 

Acknowledgements

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.

References

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First citationBurla, M. C., Caliandro, R., Camalli, M., Carrozzini, B., Cascarano, G. L., De Caro, L., Giacovazzo, C., Polidori, G. & Spagna, R. (2005). J. Appl. Cryst. 38, 381–388.  Web of Science CrossRef CAS IUCr Journals
First citationSheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationXie, S., Hou, Y., Meyers, C. Y. & Robinson, P. D. (2002). Acta Cryst. E58, o1460–o1462.  Web of Science CSD CrossRef IUCr Journals
First citationXie, S., Kenny, C. & Robinson, P. D. (2007a). Acta Cryst. E63, o3897.  Web of Science CSD CrossRef IUCr Journals
First citationXie, S., Kenny, C. & Robinson, P. D. (2007b). Acta Cryst. E63, o1660–o1662.  Web of Science CSD CrossRef IUCr Journals
First citationXie, S., Meyers, C. Y. & Robinson, P. D. (2004). Acta Cryst. E60, o1362–o1364.  Web of Science CSD CrossRef IUCr Journals
First citationXie, S., O'Hearn, C. R. & Robinson, P. D. (2008). Acta Cryst. E64, o554.  Web of Science CSD CrossRef IUCr Journals

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