Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807041098/om2154sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807041098/om2154Isup2.hkl |
CCDC reference: 662417
Key indicators
- Single-crystal X-ray study
- T = 100 K
- Mean (C-C) = 0.003 Å
- R factor = 0.058
- wR factor = 0.150
- Data-to-parameter ratio = 15.9
checkCIF/PLATON results
No syntax errors found
Alert level B ABSTM02_ALERT_3_B The ratio of expected to reported Tmax/Tmin(RR') is < 0.75 Tmin and Tmax reported: 0.600 0.989 Tmin(prime) and Tmax expected: 0.969 0.989 RR(prime) = 0.619 Please check that your absorption correction is appropriate. PLAT061_ALERT_3_B Tmax/Tmin Range Test RR' too Large ............. 0.62 PLAT220_ALERT_2_B Large Non-Solvent C Ueq(max)/Ueq(min) ... 3.97 Ratio PLAT222_ALERT_3_B Large Non-Solvent H Ueq(max)/Ueq(min) ... 4.87 Ratio PLAT230_ALERT_2_B Hirshfeld Test Diff for C15 - C16 .. 11.16 su
Alert level C PLAT230_ALERT_2_C Hirshfeld Test Diff for C9 - C10 .. 5.15 su PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor .... 2.95 PLAT481_ALERT_4_C Long D...A H-Bond Reported C3 .. CG1 .. 4.07 Ang.
Alert level G PLAT793_ALERT_1_G Check the Absolute Configuration of C2 = ... S PLAT793_ALERT_1_G Check the Absolute Configuration of C5 = ... R PLAT793_ALERT_1_G Check the Absolute Configuration of C6 = ... R
0 ALERT level A = In general: serious problem 5 ALERT level B = Potentially serious problem 3 ALERT level C = Check and explain 3 ALERT level G = General alerts; check 3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 4 ALERT type 2 Indicator that the structure model may be wrong or deficient 3 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
The carboxylic acid (I) was synthesized following the same method reported by Xie et al. (2002a). Purified (I) was recrystallized from hexane-ethyl acetate as colorless crystals (m.p. 490.5–492.0 K).
The rotational orientations of the methyl H atoms were refined by the circular Fourier method available in SHELXL97 (Sheldrick, 1997); the hydroxyl H atom position was determined in a similar manner. All H atoms were treated as riding with C—H distances ranging from 0.84 to 1.0 Å and Uiso(H) values equal to 1.5 (hydroxyl and methyl H atoms) or 1.2 times (all other H atoms) Ueq of the parent atom.
The title carboxylic acid, (I), was prepared to study the interaction of the two enantiomers in the solid state. The resultant racemate is made up of carboxylic acid RS dimers, a phenomenon similar to an analog compound we reported previously (Xie et al., 2002a). The structure and atom numbering of (I) are shown in Fig. 1, which illustrates the twisted chair conformation of the cyclohexene ring. The torsion angles involving atoms C8, C2, C1, C6, and C11 are all near 180°. The C3═C4 double bond is not fully conjugated with the benzene ring due to the steric hindrance of the C5-ethyl group, a condition which causes the benzene ring plane to rotate by 44.8 (2)° with respect to the C3—C4—C5 plane. Geometric parameters of interest are given in Table 1.
Fig. 2 shows the hydrogen-bonding scheme, molecular packing and C—H···π(arene) interactions. Atom O2 acts as a donor in an intermolecular hydrogen bond to atom O1. Inversion of this interaction across (1/2, 1/2, 1) produces an R22(8) ring (Bernstein et al., 1995), thus creating a hydrogen-bonded dimer. The dimers are interconnected via weak C—H···π(arene) interactions in both the b and c directions, forming thick two-dimensional layers parallel to (100). Geometry of these two interactions is given in Table 2.
In the 4-p-methoxyphenyl analog (Xie et al., 2002a), the racemate also consists of carboxylic acid RS dimers. For additional related literature, see: Bernstein et al. (1995); Hussain et al. (2006); Xie et al. (2002b, 2007).
Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005) and SADABS (Bruker, 2005); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: LS in TEXSAN (Molecular Structure Corporation, 1997) and SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997) and PLATON (Spek, 2003).
C18H24O2 | F(000) = 592 |
Mr = 272.37 | Dx = 1.199 Mg m−3 |
Monoclinic, P21/c | Melting point = 490.5–492 K |
Hall symbol: -P 2ybc | Mo Kα radiation, λ = 0.71073 Å |
a = 16.2786 (14) Å | Cell parameters from 2703 reflections |
b = 11.472 (1) Å | θ = 2.5–28.2° |
c = 8.1035 (7) Å | µ = 0.08 mm−1 |
β = 94.318 (5)° | T = 100 K |
V = 1509.0 (2) Å3 | Irregular fragment, colorless |
Z = 4 | 0.41 × 0.17 × 0.15 mm |
Bruker Kappa APEX II CCD diffractometer | 2952 independent reflections |
Radiation source: X-ray tube | 2211 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.054 |
φ and ω scans | θmax = 26.0°, θmin = 2.2° |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | h = −20→20 |
Tmin = 0.600, Tmax = 0.989 | k = −14→13 |
19084 measured reflections | l = −9→6 |
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)] = 0.058 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.150 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0587P)2 + 1.3904P] where P = (Fo2 + 2Fc2)/3 |
2952 reflections | (Δ/σ)max < 0.001 |
186 parameters | Δρmax = 0.55 e Å−3 |
0 restraints | Δρmin = −0.46 e Å−3 |
C18H24O2 | V = 1509.0 (2) Å3 |
Mr = 272.37 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 16.2786 (14) Å | µ = 0.08 mm−1 |
b = 11.472 (1) Å | T = 100 K |
c = 8.1035 (7) Å | 0.41 × 0.17 × 0.15 mm |
β = 94.318 (5)° |
Bruker Kappa APEX II CCD diffractometer | 2952 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | 2211 reflections with I > 2σ(I) |
Tmin = 0.600, Tmax = 0.989 | Rint = 0.054 |
19084 measured reflections |
R[F2 > 2σ(F2)] = 0.058 | 0 restraints |
wR(F2) = 0.150 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.55 e Å−3 |
2952 reflections | Δρmin = −0.46 e Å−3 |
186 parameters |
x | y | z | Uiso*/Ueq | ||
O1 | 0.40575 (9) | 0.49053 (13) | 0.91934 (17) | 0.0244 (4) | |
O2 | 0.51667 (8) | 0.52472 (14) | 0.78147 (17) | 0.0260 (4) | |
H2 | 0.5406 | 0.5183 | 0.8765 | 0.039* | |
C1 | 0.38654 (12) | 0.52324 (17) | 0.6275 (2) | 0.0194 (4) | |
H1 | 0.4249 | 0.5350 | 0.5382 | 0.023* | |
C2 | 0.33118 (12) | 0.63081 (17) | 0.6339 (2) | 0.0199 (4) | |
H2A | 0.2996 | 0.6253 | 0.7347 | 0.024* | |
C3 | 0.27101 (13) | 0.63237 (18) | 0.4839 (3) | 0.0242 (5) | |
H3 | 0.2436 | 0.7038 | 0.4571 | 0.029* | |
C4 | 0.25300 (12) | 0.54117 (18) | 0.3853 (2) | 0.0218 (5) | |
C5 | 0.28849 (14) | 0.42135 (19) | 0.4199 (3) | 0.0296 (5) | |
H5 | 0.3288 | 0.4069 | 0.3350 | 0.035* | |
C6 | 0.33676 (13) | 0.41179 (17) | 0.5894 (3) | 0.0233 (5) | |
H6 | 0.2964 | 0.4024 | 0.6757 | 0.028* | |
C7 | 0.43691 (12) | 0.51111 (16) | 0.7900 (2) | 0.0188 (4) | |
C8 | 0.38172 (13) | 0.74326 (18) | 0.6440 (3) | 0.0265 (5) | |
H8A | 0.4134 | 0.7496 | 0.5462 | 0.040* | |
H8B | 0.4195 | 0.7420 | 0.7440 | 0.040* | |
H8C | 0.3446 | 0.8103 | 0.6481 | 0.040* | |
C9 | 0.22227 (16) | 0.3268 (2) | 0.3955 (3) | 0.0395 (6) | |
H9A | 0.2021 | 0.3252 | 0.2771 | 0.047* | |
H9B | 0.2480 | 0.2503 | 0.4225 | 0.047* | |
C10 | 0.14949 (17) | 0.3420 (3) | 0.4977 (4) | 0.0529 (8) | |
H10A | 0.1685 | 0.3434 | 0.6153 | 0.079* | |
H10B | 0.1111 | 0.2769 | 0.4764 | 0.079* | |
H10C | 0.1215 | 0.4155 | 0.4677 | 0.079* | |
C11 | 0.39292 (15) | 0.30511 (19) | 0.5954 (3) | 0.0309 (5) | |
H11A | 0.3599 | 0.2350 | 0.5705 | 0.046* | |
H11B | 0.4211 | 0.2981 | 0.7061 | 0.046* | |
H11C | 0.4338 | 0.3137 | 0.5134 | 0.046* | |
C12 | 0.19862 (13) | 0.55613 (18) | 0.2308 (3) | 0.0264 (5) | |
C13 | 0.22078 (15) | 0.5074 (2) | 0.0822 (3) | 0.0363 (6) | |
H13 | 0.2707 | 0.4646 | 0.0815 | 0.044* | |
C14 | 0.17192 (17) | 0.5200 (3) | −0.0628 (3) | 0.0451 (7) | |
H14 | 0.1888 | 0.4860 | −0.1616 | 0.054* | |
C15 | 0.09955 (19) | 0.5806 (3) | −0.0673 (3) | 0.0482 (8) | |
C16 | 0.07687 (17) | 0.6306 (3) | 0.0789 (4) | 0.0531 (8) | |
H16 | 0.0271 | 0.6739 | 0.0781 | 0.064* | |
C17 | 0.12617 (15) | 0.6183 (2) | 0.2270 (3) | 0.0375 (6) | |
H17 | 0.1095 | 0.6531 | 0.3255 | 0.045* | |
C18 | 0.0446 (2) | 0.5926 (3) | −0.2266 (4) | 0.0746 (12) | |
H18A | 0.0757 | 0.6293 | −0.3116 | 0.112* | |
H18B | −0.0032 | 0.6409 | −0.2064 | 0.112* | |
H18C | 0.0259 | 0.5152 | −0.2646 | 0.112* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0239 (8) | 0.0327 (8) | 0.0157 (7) | −0.0019 (6) | −0.0042 (6) | 0.0032 (6) |
O2 | 0.0230 (8) | 0.0367 (9) | 0.0174 (7) | −0.0017 (6) | −0.0054 (6) | 0.0045 (7) |
C1 | 0.0233 (10) | 0.0190 (10) | 0.0151 (10) | −0.0021 (8) | −0.0044 (8) | 0.0008 (8) |
C2 | 0.0244 (10) | 0.0193 (10) | 0.0154 (10) | 0.0017 (8) | −0.0038 (8) | −0.0007 (8) |
C3 | 0.0256 (11) | 0.0241 (11) | 0.0221 (11) | 0.0034 (9) | −0.0042 (9) | 0.0029 (9) |
C4 | 0.0216 (10) | 0.0230 (10) | 0.0199 (10) | −0.0038 (8) | −0.0044 (8) | 0.0042 (8) |
C5 | 0.0380 (13) | 0.0240 (11) | 0.0245 (12) | −0.0038 (10) | −0.0119 (10) | 0.0007 (9) |
C6 | 0.0280 (11) | 0.0192 (10) | 0.0214 (11) | −0.0022 (8) | −0.0077 (8) | 0.0014 (8) |
C7 | 0.0230 (10) | 0.0143 (9) | 0.0183 (10) | −0.0002 (8) | −0.0038 (8) | −0.0007 (8) |
C8 | 0.0319 (12) | 0.0206 (11) | 0.0263 (12) | −0.0001 (9) | −0.0033 (9) | −0.0013 (9) |
C9 | 0.0514 (15) | 0.0252 (12) | 0.0379 (14) | −0.0123 (11) | −0.0234 (12) | 0.0060 (10) |
C10 | 0.0462 (16) | 0.0547 (17) | 0.0531 (18) | −0.0244 (14) | −0.0270 (14) | 0.0263 (14) |
C11 | 0.0401 (13) | 0.0215 (11) | 0.0294 (12) | 0.0016 (10) | −0.0077 (10) | −0.0003 (9) |
C12 | 0.0293 (12) | 0.0235 (11) | 0.0246 (11) | −0.0097 (9) | −0.0094 (9) | 0.0076 (9) |
C13 | 0.0360 (13) | 0.0472 (15) | 0.0244 (12) | −0.0151 (11) | −0.0060 (10) | 0.0032 (11) |
C14 | 0.0464 (16) | 0.0629 (18) | 0.0241 (13) | −0.0255 (14) | −0.0100 (11) | 0.0075 (12) |
C15 | 0.0627 (19) | 0.0496 (16) | 0.0288 (14) | −0.0275 (14) | −0.0196 (13) | 0.0142 (12) |
C16 | 0.0407 (15) | 0.0444 (16) | 0.069 (2) | −0.0003 (12) | −0.0292 (14) | 0.0159 (15) |
C17 | 0.0370 (13) | 0.0334 (13) | 0.0392 (14) | −0.0016 (10) | −0.0168 (11) | 0.0046 (11) |
C18 | 0.084 (2) | 0.081 (2) | 0.0512 (19) | −0.037 (2) | −0.0441 (18) | 0.0289 (18) |
O1—C7 | 1.221 (2) | C9—H9A | 0.9900 |
O2—C7 | 1.315 (2) | C9—H9B | 0.9900 |
O2—H2 | 0.8400 | C10—H10A | 0.9800 |
C1—C7 | 1.504 (3) | C10—H10B | 0.9800 |
C1—C2 | 1.531 (3) | C10—H10C | 0.9800 |
C1—C6 | 1.533 (3) | C11—H11A | 0.9800 |
C1—H1 | 1.0000 | C11—H11B | 0.9800 |
C2—C3 | 1.503 (3) | C11—H11C | 0.9800 |
C2—C8 | 1.529 (3) | C12—C17 | 1.377 (3) |
C2—H2A | 1.0000 | C12—C13 | 1.399 (3) |
C3—C4 | 1.336 (3) | C13—C14 | 1.376 (3) |
C3—H3 | 0.9500 | C13—H13 | 0.9500 |
C4—C12 | 1.488 (3) | C14—C15 | 1.366 (4) |
C4—C5 | 1.509 (3) | C14—H14 | 0.9500 |
C5—C9 | 1.531 (3) | C15—C16 | 1.391 (4) |
C5—C6 | 1.534 (3) | C15—C18 | 1.520 (3) |
C5—H5 | 1.0000 | C16—C17 | 1.400 (3) |
C6—C11 | 1.526 (3) | C16—H16 | 0.9500 |
C6—H6 | 1.0000 | C17—H17 | 0.9500 |
C8—H8A | 0.9800 | C18—H18A | 0.9800 |
C8—H8B | 0.9800 | C18—H18B | 0.9800 |
C8—H8C | 0.9800 | C18—H18C | 0.9800 |
C9—C10 | 1.506 (4) | ||
C7—O2—H2 | 109.5 | C10—C9—H9A | 108.5 |
C7—C1—C2 | 109.17 (16) | C5—C9—H9A | 108.5 |
C7—C1—C6 | 110.13 (16) | C10—C9—H9B | 108.5 |
C2—C1—C6 | 112.06 (16) | C5—C9—H9B | 108.5 |
C7—C1—H1 | 108.5 | H9A—C9—H9B | 107.5 |
C2—C1—H1 | 108.5 | C9—C10—H10A | 109.5 |
C6—C1—H1 | 108.5 | C9—C10—H10B | 109.5 |
C3—C2—C8 | 110.39 (17) | H10A—C10—H10B | 109.5 |
C3—C2—C1 | 109.38 (16) | C9—C10—H10C | 109.5 |
C8—C2—C1 | 111.48 (16) | H10A—C10—H10C | 109.5 |
C3—C2—H2A | 108.5 | H10B—C10—H10C | 109.5 |
C8—C2—H2A | 108.5 | C6—C11—H11A | 109.5 |
C1—C2—H2A | 108.5 | C6—C11—H11B | 109.5 |
C4—C3—C2 | 125.09 (19) | H11A—C11—H11B | 109.5 |
C4—C3—H3 | 117.5 | C6—C11—H11C | 109.5 |
C2—C3—H3 | 117.5 | H11A—C11—H11C | 109.5 |
C3—C4—C12 | 120.19 (19) | H11B—C11—H11C | 109.5 |
C3—C4—C5 | 122.59 (18) | C17—C12—C13 | 117.6 (2) |
C12—C4—C5 | 117.18 (18) | C17—C12—C4 | 122.2 (2) |
C4—C5—C9 | 111.40 (19) | C13—C12—C4 | 120.2 (2) |
C4—C5—C6 | 113.25 (17) | C14—C13—C12 | 121.5 (3) |
C9—C5—C6 | 111.93 (18) | C14—C13—H13 | 119.2 |
C4—C5—H5 | 106.6 | C12—C13—H13 | 119.2 |
C9—C5—H5 | 106.6 | C15—C14—C13 | 121.2 (3) |
C6—C5—H5 | 106.6 | C15—C14—H14 | 119.4 |
C11—C6—C1 | 110.87 (17) | C13—C14—H14 | 119.4 |
C11—C6—C5 | 110.55 (18) | C14—C15—C16 | 118.1 (2) |
C1—C6—C5 | 110.37 (16) | C14—C15—C18 | 121.3 (3) |
C11—C6—H6 | 108.3 | C16—C15—C18 | 120.6 (3) |
C1—C6—H6 | 108.3 | C15—C16—C17 | 121.1 (3) |
C5—C6—H6 | 108.3 | C15—C16—H16 | 119.5 |
O1—C7—O2 | 122.94 (18) | C17—C16—H16 | 119.5 |
O1—C7—C1 | 122.33 (18) | C12—C17—C16 | 120.4 (3) |
O2—C7—C1 | 114.73 (17) | C12—C17—H17 | 119.8 |
C2—C8—H8A | 109.5 | C16—C17—H17 | 119.8 |
C2—C8—H8B | 109.5 | C15—C18—H18A | 109.5 |
H8A—C8—H8B | 109.5 | C15—C18—H18B | 109.5 |
C2—C8—H8C | 109.5 | H18A—C18—H18B | 109.5 |
H8A—C8—H8C | 109.5 | C15—C18—H18C | 109.5 |
H8B—C8—H8C | 109.5 | H18A—C18—H18C | 109.5 |
C10—C9—C5 | 115.0 (2) | H18B—C18—H18C | 109.5 |
C3—C4—C12—C13 | 133.7 (2) | C4—C5—C6—C1 | −38.9 (3) |
C3—C4—C12—C17 | −45.6 (3) | C9—C5—C6—C1 | −165.82 (19) |
C6—C1—C2—C8 | −170.80 (17) | C2—C1—C7—O1 | 65.4 (2) |
C2—C1—C6—C11 | −176.17 (17) | C6—C1—C7—O1 | −58.0 (2) |
C7—C1—C2—C3 | −170.71 (16) | C2—C1—C7—O2 | −114.42 (19) |
C7—C1—C6—C5 | −177.26 (17) | C6—C1—C7—O2 | 122.14 (19) |
C6—C1—C2—C3 | −48.4 (2) | C4—C5—C9—C10 | −56.7 (3) |
C7—C1—C2—C8 | 66.9 (2) | C6—C5—C9—C10 | 71.2 (3) |
C8—C2—C3—C4 | 139.8 (2) | C5—C4—C12—C17 | 136.7 (2) |
C1—C2—C3—C4 | 16.8 (3) | C5—C4—C12—C13 | −44.0 (3) |
C2—C3—C4—C12 | −173.91 (19) | C17—C12—C13—C14 | −0.5 (3) |
C2—C3—C4—C5 | 3.6 (3) | C4—C12—C13—C14 | −179.8 (2) |
C3—C4—C5—C9 | 135.2 (2) | C12—C13—C14—C15 | −0.2 (4) |
C12—C4—C5—C9 | −47.2 (3) | C13—C14—C15—C16 | 0.8 (4) |
C3—C4—C5—C6 | 7.9 (3) | C13—C14—C15—C18 | −178.7 (2) |
C12—C4—C5—C6 | −174.46 (18) | C14—C15—C16—C17 | −0.8 (4) |
C7—C1—C6—C11 | −54.4 (2) | C18—C15—C16—C17 | 178.8 (3) |
C2—C1—C6—C5 | 61.0 (2) | C13—C12—C17—C16 | 0.5 (3) |
C4—C5—C6—C11 | −161.90 (19) | C4—C12—C17—C16 | 179.8 (2) |
C9—C5—C6—C11 | 71.2 (3) | C15—C16—C17—C12 | 0.1 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O1i | 0.84 | 1.81 | 2.654 (2) | 178 |
C3—H3···Cg1ii | 0.95 | 3.23 | 4.069 (2) | 148 |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) x, −y+3/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C18H24O2 |
Mr | 272.37 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 100 |
a, b, c (Å) | 16.2786 (14), 11.472 (1), 8.1035 (7) |
β (°) | 94.318 (5) |
V (Å3) | 1509.0 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.41 × 0.17 × 0.15 |
Data collection | |
Diffractometer | Bruker Kappa APEX II CCD |
Absorption correction | Multi-scan (SADABS; Bruker, 2005) |
Tmin, Tmax | 0.600, 0.989 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 19084, 2952, 2211 |
Rint | 0.054 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.058, 0.150, 1.03 |
No. of reflections | 2952 |
No. of parameters | 186 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.55, −0.46 |
Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005) and SADABS (Bruker, 2005), SIR92 (Altomare et al., 1994), LS in TEXSAN (Molecular Structure Corporation, 1997) and SHELXL97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997) and PLATON (Spek, 2003).
C3—C4—C12—C13 | 133.7 (2) | C2—C1—C6—C11 | −176.17 (17) |
C3—C4—C12—C17 | −45.6 (3) | C7—C1—C2—C3 | −170.71 (16) |
C6—C1—C2—C8 | −170.80 (17) | C7—C1—C6—C5 | −177.26 (17) |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O1i | 0.84 | 1.81 | 2.654 (2) | 178 |
C3—H3···Cg1ii | 0.95 | 3.23 | 4.069 (2) | 148 |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) x, −y+3/2, z+1/2. |
The title carboxylic acid, (I), was prepared to study the interaction of the two enantiomers in the solid state. The resultant racemate is made up of carboxylic acid RS dimers, a phenomenon similar to an analog compound we reported previously (Xie et al., 2002a). The structure and atom numbering of (I) are shown in Fig. 1, which illustrates the twisted chair conformation of the cyclohexene ring. The torsion angles involving atoms C8, C2, C1, C6, and C11 are all near 180°. The C3═C4 double bond is not fully conjugated with the benzene ring due to the steric hindrance of the C5-ethyl group, a condition which causes the benzene ring plane to rotate by 44.8 (2)° with respect to the C3—C4—C5 plane. Geometric parameters of interest are given in Table 1.
Fig. 2 shows the hydrogen-bonding scheme, molecular packing and C—H···π(arene) interactions. Atom O2 acts as a donor in an intermolecular hydrogen bond to atom O1. Inversion of this interaction across (1/2, 1/2, 1) produces an R22(8) ring (Bernstein et al., 1995), thus creating a hydrogen-bonded dimer. The dimers are interconnected via weak C—H···π(arene) interactions in both the b and c directions, forming thick two-dimensional layers parallel to (100). Geometry of these two interactions is given in Table 2.