PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. 2008 September 1; 64(Pt 9): o1664.
Published online 2008 August 6. doi:  10.1107/S1600536808024112
PMCID: PMC2960648

(±)-trans-3-Benzoyl­bicyclo­[2.2.2]octane-2-carboxylic acid

Abstract

The title keto acid, C16H18O3, displays significant twisting of all three ethyl­ene bridges in its bicyclo­[2.2.2]octane structure owing to steric inter­actions; the bridgehead-to-bridgehead torsion angles are 13.14 (12), 13.14 (13) and 9.37 (13)°. The compound crystallizes as centrosymmetric carboxyl dimers [O(...)O = 2.6513 (12) Å and O—H(...)O = 178°], which have two orientations within the cell and contain no significant carboxyl disorder.

Related literature

For related literature, see: Blackstock et al. (1987 [triangle]); Deutsch (1972 [triangle]); Scribner & Miller (1965 [triangle]); Zimmerman et al. (1992 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-o1664-scheme1.jpg

Experimental

Crystal data

  • C16H18O3
  • M r = 258.30
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-o1664-efi1.jpg
  • a = 7.9155 (7) Å
  • b = 11.1129 (9) Å
  • c = 14.7559 (12) Å
  • β = 93.882 (3)°
  • V = 1295.01 (19) Å3
  • Z = 4
  • Cu Kα radiation
  • μ = 0.73 mm−1
  • T = 100 (2) K
  • 0.49 × 0.30 × 0.17 mm

Data collection

  • Bruker SMART CCD APEXII area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 2001 [triangle]) T min = 0.716, T max = 0.886
  • 7983 measured reflections
  • 2405 independent reflections
  • 2350 reflections with I > 2σ(I)
  • R int = 0.029

Refinement

  • R[F 2 > 2σ(F 2)] = 0.038
  • wR(F 2) = 0.100
  • S = 1.03
  • 2405 reflections
  • 174 parameters
  • H-atom parameters constrained
  • Δρmax = 0.33 e Å−3
  • Δρmin = −0.20 e Å−3

Data collection: APEX2 (Bruker, 2006 [triangle]); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005 [triangle]); program(s) used to solve structure: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808024112/fl2213sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808024112/fl2213Isup2.hkl

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

Acknowledgments

HWT is grateful to Professor Gree Loober Spoog for helpful consultations. The authors acknowledge support by NSF–CRIF grant No. 0443538.

supplementary crystallographic information

Comment

Our study of crystalline keto acids concerns their repertoire of five known H-bonding modes. Two of these lack ketone involvement, including the commonest, acid dimerization, which is found in the aggregation of the title compound (I).

Fig. 1 shows the asymmetric unit of (I) with its numbering. Even simple bicyclo[2.2.2]octane systems often adopt a twist about the threefold axis, presumably to relieve eclipsing strain in their ethylene bridges (Deutsch, 1972; Blackstock et al., 1987; Zimmerman et al., 1992). In (I) that strain is supplemented by more serious eclipsing and 1,3-diaxial interactions involving the substituents, so that all three bridges are significantly twisted. Fig. 1 illustrates the extent to which the C5—C6 ethylene bridge is clearly not parallel to the others; however, the appearance of parallelism in the C2—C3 and C7—C8 bridges is an artifact of the viewing angle. The torsion angles for the three bridges are: C1—C2—C3—C4 = 13.14 (12)°, C1—C6—C5—C4 = 13.14 (13)°, C1—C7—C8—C4 = 9.37 (13)°.

The benzoyl group has component parts that are only approximately coplanar [the dihedral angle for C3—C10—C11—O1 versus the aromatic ring = 24.60 (7)°], and is oriented so that the ketone C=O is aimed toward C2. The carboxyl group is turned, with its C=O toward C3, so that the O2—C9—C2—C3 torsion angle is 18.76 (15)°. The dihedral angle between the ketone (C3—C10—C11—O1) and carboxyl group (C2—C9—O2—O3) is 79.80 (4)°. One may envision other possible conformations for the phenyl ring; however, because of steric hindrance, there is very little rotational freedom for the phenyl group here.

Although carboxyl dimers frequently display complete or partial averaging of C—O bond lengths and C—C—O angles due to disorder, no significant averaging is observed in (I), where these lengths and angles are similar to those in other highly ordered dimeric carboxyls.

Fig. 2 shows the packing for (I), typical for racemic keto acids that are dimeric. Centrosymmetric dimers are centered at 1/2,1/2,1/2 in the chosen cell, with a second screw-related set centered on the a cell edge. No close intermolecular contacts were found within the 2.6 Å range we routinely survey for non-bonded C—H···O packing interactions.

Experimental

endo-Bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, purchased from Aldrich Chemical Co., Milwaukee, Wisconsin, USA, was hydrogenated under typical conditions (atmospheric pressure, room temperature, 5%Pd/C, EtOAc) and the isolated product used directly in a Friedel-Crafts acylation of benzene (AlCl3). The cis keto acid initially obtained (mp 446 K) was epimerized by refluxing in excess aqueous KOH (Scribner & Miller, 1965). The isolated trans product (I) was vacuum-distilled and crystallized from acetonitrile to give the crystal used, mp 444 K.

The solid-state IR spectrum (KBr) of (I) has C=O absorptions at 1692 (acid) and 1677 cm-1 (ketone), normal for dimerized COOH and for a benzoyl group without H bonding but with significant coplanarity. In CHCl3 solution these peaks appear at 1702 & 1679 cm-1.

Refinement

All H atoms for (I) were found in electron density difference maps. The O—H was constrained to an idealized position with its distance fixed at 0.84 Å and Uiso(H) = 1.5Ueq(O). The methylene, methine and aromatic Hs were placed in geometrically idealized positions and constrained to ride on their parent C atoms with C—H distances of 0.99, 1.00 and 0.95 Å, respectively, and Uiso(H) = 1.2Ueq(C).

Figures

Fig. 1.
The asymmetric unit with its numbering. Displacement ellipsoids are drawn at the 40% probability level.
Fig. 2.
A partial packing diagram, with an extracellular molecule included to show the dimers centered at 1/2,1/2,1/2 and 1/2,0,0. For clarity, all C-bound H atoms are omitted. Displacement ellipsoids are drawn at the 40% probability level.

Crystal data

C16H18O3F000 = 552
Mr = 258.30Dx = 1.325 Mg m3
Monoclinic, P21/cMelting point: 444 K
Hall symbol: -P 2ybcCu Kα radiation λ = 1.54178 Å
a = 7.9155 (7) ÅCell parameters from 7078 reflections
b = 11.1129 (9) Åθ = 3.0–69.4º
c = 14.7559 (12) ŵ = 0.73 mm1
β = 93.882 (3)ºT = 100 (2) K
V = 1295.01 (19) Å3Block, colourless
Z = 40.49 × 0.30 × 0.17 mm

Data collection

Bruker SMART CCD APEXII area-detector diffractometer2405 independent reflections
Radiation source: fine-focus sealed tube2350 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.029
T = 100(2) Kθmax = 69.8º
[var phi] and ω scansθmin = 5.0º
Absorption correction: multi-scan(SADABS; Sheldrick, 2001)h = −8→9
Tmin = 0.716, Tmax = 0.886k = −13→11
7983 measured reflectionsl = −16→17

Refinement

Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.038  w = 1/[σ2(Fo2) + (0.0502P)2 + 0.6168P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.100(Δ/σ)max < 0.001
S = 1.03Δρmax = 0.33 e Å3
2405 reflectionsΔρmin = −0.20 e Å3
174 parametersExtinction correction: SHELXTL (Sheldrick, 2004), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0033 (6)
Secondary atom site location: difference Fourier map

Special details

Experimental. crystal mounted on cryoloop using Paratone-N
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
O10.61369 (11)0.84095 (8)0.26798 (6)0.0210 (2)
C10.15616 (14)0.72901 (11)0.34151 (8)0.0160 (3)
H1A0.11780.73680.40440.019*
O20.53283 (11)0.55007 (8)0.39852 (6)0.0188 (2)
C20.35047 (14)0.71209 (10)0.34504 (8)0.0141 (3)
H2A0.40340.79060.36410.017*
O30.33736 (12)0.61674 (8)0.48872 (6)0.0219 (2)
H30.38070.56380.52360.033*
C30.40618 (14)0.68316 (10)0.24926 (7)0.0135 (3)
H3A0.43270.59530.24650.016*
C40.25626 (14)0.71016 (10)0.17863 (8)0.0148 (3)
H4A0.29460.70280.11570.018*
C50.19028 (15)0.83791 (10)0.19406 (8)0.0169 (3)
H5A0.10550.85990.14440.020*
H5B0.28490.89610.19410.020*
C60.10856 (15)0.84268 (11)0.28620 (8)0.0181 (3)
H6A0.14870.91500.32040.022*
H6B−0.01610.84800.27580.022*
C70.06974 (15)0.62064 (11)0.29348 (8)0.0188 (3)
H7A−0.05460.62720.29590.023*
H7B0.10730.54530.32450.023*
C80.11666 (15)0.61758 (11)0.19320 (8)0.0180 (3)
H8A0.15670.53610.17800.022*
H8B0.01530.63610.15260.022*
C90.41562 (14)0.61797 (10)0.41280 (8)0.0147 (3)
C100.56183 (14)0.75308 (10)0.22505 (8)0.0147 (3)
C110.64421 (14)0.71562 (11)0.14064 (8)0.0154 (3)
C120.73488 (15)0.80248 (11)0.09565 (8)0.0191 (3)
H12A0.74670.88120.12040.023*
C130.80759 (16)0.77527 (12)0.01549 (9)0.0230 (3)
H13A0.86690.8356−0.01520.028*
C140.79381 (16)0.65959 (13)−0.02018 (9)0.0245 (3)
H14A0.84380.6406−0.07520.029*
C150.70687 (16)0.57201 (13)0.02484 (9)0.0246 (3)
H15A0.69960.49260.00110.030*
C160.63028 (15)0.59953 (11)0.10437 (8)0.0196 (3)
H16A0.56860.53960.13400.024*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0203 (4)0.0220 (5)0.0208 (4)−0.0053 (3)0.0021 (3)−0.0048 (3)
C10.0145 (6)0.0178 (6)0.0162 (6)0.0030 (4)0.0036 (4)0.0026 (4)
O20.0193 (4)0.0220 (4)0.0154 (4)0.0064 (3)0.0022 (3)0.0017 (3)
C20.0148 (6)0.0136 (5)0.0141 (6)0.0005 (4)0.0015 (4)−0.0004 (4)
O30.0241 (5)0.0278 (5)0.0141 (4)0.0107 (4)0.0039 (3)0.0053 (3)
C30.0135 (5)0.0135 (5)0.0136 (5)0.0009 (4)0.0013 (4)−0.0002 (4)
C40.0132 (5)0.0168 (6)0.0144 (5)−0.0004 (4)−0.0001 (4)0.0002 (4)
C50.0161 (6)0.0164 (6)0.0181 (6)0.0010 (4)0.0005 (5)0.0035 (4)
C60.0179 (6)0.0166 (6)0.0198 (6)0.0044 (4)0.0021 (5)0.0012 (5)
C70.0147 (6)0.0188 (6)0.0230 (6)−0.0016 (4)0.0017 (5)0.0052 (5)
C80.0150 (6)0.0175 (6)0.0214 (6)−0.0018 (4)−0.0003 (5)−0.0014 (5)
C90.0146 (5)0.0156 (6)0.0137 (5)−0.0005 (4)−0.0007 (4)−0.0017 (4)
C100.0128 (5)0.0159 (6)0.0150 (6)0.0016 (4)−0.0015 (4)0.0015 (4)
C110.0106 (5)0.0203 (6)0.0152 (6)0.0016 (4)−0.0013 (4)0.0012 (4)
C120.0158 (6)0.0195 (6)0.0219 (6)0.0014 (5)0.0012 (5)0.0023 (5)
C130.0175 (6)0.0298 (7)0.0220 (6)0.0012 (5)0.0037 (5)0.0069 (5)
C140.0179 (6)0.0401 (8)0.0157 (6)−0.0002 (5)0.0027 (5)−0.0037 (5)
C150.0213 (6)0.0291 (7)0.0237 (6)−0.0034 (5)0.0032 (5)−0.0094 (5)
C160.0167 (6)0.0214 (6)0.0209 (6)−0.0025 (5)0.0028 (5)−0.0020 (5)

Geometric parameters (Å, °)

O1—C101.2199 (15)C6—H6A0.9900
C1—C71.5346 (17)C6—H6B0.9900
C1—C61.5369 (16)C7—C81.5503 (17)
C1—C21.5469 (15)C7—H7A0.9900
C1—H1A1.0000C7—H7B0.9900
O2—C91.2251 (15)C8—H8A0.9900
C2—C91.5132 (16)C8—H8B0.9900
C2—C31.5426 (15)C10—C111.5033 (16)
C2—H2A1.0000C11—C121.3971 (17)
O3—C91.3164 (14)C11—C161.3982 (17)
O3—H30.8400C12—C131.3835 (18)
C3—C101.5195 (15)C12—H12A0.9500
C3—C41.5547 (15)C13—C141.391 (2)
C3—H3A1.0000C13—H13A0.9500
C4—C51.5349 (16)C14—C151.387 (2)
C4—C81.5356 (16)C14—H14A0.9500
C4—H4A1.0000C15—C161.3910 (17)
C5—C61.5456 (16)C15—H15A0.9500
C5—H5A0.9900C16—H16A0.9500
C5—H5B0.9900
C7—C1—C6108.31 (10)C1—C7—C8109.27 (9)
C7—C1—C2109.35 (9)C1—C7—H7A109.8
C6—C1—C2108.98 (9)C8—C7—H7A109.8
C7—C1—H1A110.1C1—C7—H7B109.8
C6—C1—H1A110.1C8—C7—H7B109.8
C2—C1—H1A110.1H7A—C7—H7B108.3
C9—C2—C3110.83 (9)C4—C8—C7109.89 (9)
C9—C2—C1113.57 (9)C4—C8—H8A109.7
C3—C2—C1109.86 (9)C7—C8—H8A109.7
C9—C2—H2A107.4C4—C8—H8B109.7
C3—C2—H2A107.4C7—C8—H8B109.7
C1—C2—H2A107.4H8A—C8—H8B108.2
C9—O3—H3109.5O2—C9—O3123.05 (10)
C10—C3—C2113.29 (9)O2—C9—C2122.70 (10)
C10—C3—C4109.75 (9)O3—C9—C2114.24 (9)
C2—C3—C4108.75 (9)O1—C10—C11120.15 (10)
C10—C3—H3A108.3O1—C10—C3122.48 (10)
C2—C3—H3A108.3C11—C10—C3117.21 (10)
C4—C3—H3A108.3C12—C11—C16119.04 (11)
C5—C4—C8110.09 (9)C12—C11—C10117.90 (11)
C5—C4—C3109.33 (9)C16—C11—C10123.04 (11)
C8—C4—C3107.50 (9)C13—C12—C11120.80 (12)
C5—C4—H4A110.0C13—C12—H12A119.6
C8—C4—H4A110.0C11—C12—H12A119.6
C3—C4—H4A110.0C12—C13—C14119.95 (12)
C4—C5—C6109.22 (9)C12—C13—H13A120.0
C4—C5—H5A109.8C14—C13—H13A120.0
C6—C5—H5A109.8C15—C14—C13119.74 (12)
C4—C5—H5B109.8C15—C14—H14A120.1
C6—C5—H5B109.8C13—C14—H14A120.1
H5A—C5—H5B108.3C14—C15—C16120.56 (12)
C1—C6—C5109.68 (9)C14—C15—H15A119.7
C1—C6—H6A109.7C16—C15—H15A119.7
C5—C6—H6A109.7C15—C16—C11119.88 (12)
C1—C6—H6B109.7C15—C16—H16A120.1
C5—C6—H6B109.7C11—C16—H16A120.1
H6A—C6—H6B108.2
C7—C1—C2—C9−73.31 (12)C1—C7—C8—C49.37 (13)
C6—C1—C2—C9168.48 (9)C3—C2—C9—O218.76 (15)
C7—C1—C2—C351.44 (12)C1—C2—C9—O2142.99 (11)
C6—C1—C2—C3−66.77 (12)C3—C2—C9—O3−162.26 (10)
C9—C2—C3—C10−98.22 (11)C1—C2—C9—O3−38.03 (13)
C1—C2—C3—C10135.46 (10)C2—C3—C10—O1−15.16 (15)
C9—C2—C3—C4139.46 (9)C4—C3—C10—O1106.60 (12)
C1—C2—C3—C413.14 (12)C2—C3—C10—C11169.41 (9)
C10—C3—C4—C5−72.95 (11)C4—C3—C10—C11−68.83 (12)
C2—C3—C4—C551.49 (12)O1—C10—C11—C12−22.30 (16)
C10—C3—C4—C8167.56 (9)C3—C10—C11—C12153.24 (10)
C2—C3—C4—C8−68.00 (11)O1—C10—C11—C16159.41 (12)
C8—C4—C5—C650.74 (12)C3—C10—C11—C16−25.06 (16)
C3—C4—C5—C6−67.14 (11)C16—C11—C12—C131.15 (18)
C7—C1—C6—C5−67.71 (12)C10—C11—C12—C13−177.22 (11)
C2—C1—C6—C551.15 (12)C11—C12—C13—C14−1.35 (19)
C4—C5—C6—C113.14 (13)C12—C13—C14—C150.09 (19)
C6—C1—C7—C854.02 (12)C13—C14—C15—C161.4 (2)
C2—C1—C7—C8−64.62 (12)C14—C15—C16—C11−1.54 (19)
C5—C4—C8—C7−64.17 (12)C12—C11—C16—C150.29 (18)
C3—C4—C8—C754.83 (12)C10—C11—C16—C15178.57 (11)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
O3—H3···O2i0.841.812.6513 (12)178

Symmetry codes: (i) −x+1, −y+1, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FL2213).

References

  • Blackstock, S. C., Lorand, J. P. & Kochi, J. K. (1987). J. Org. Chem.52, 1451–1460.
  • Bruker (2005). SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Bruker (2006). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.
  • Deutsch, E. (1972). J. Org. Chem.37, 3481–3486.
  • Scribner, J. D. & Miller, J. A. (1965). J. Chem. Soc. pp. 5377–5380.
  • Sheldrick, G. M. (2001). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Zimmerman, H. E., King, R. K. & Meinhardt, M. B. (1992). J. Org. Chem.57, 5484–5492.

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography