Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807043425/lw2029sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807043425/lw2029Isup2.hkl |
CCDC reference: 663731
Key indicators
- Single-crystal X-ray study
- T = 100 K
- Mean (C-C) = 0.002 Å
- R factor = 0.036
- wR factor = 0.095
- Data-to-parameter ratio = 13.0
checkCIF/PLATON results
No syntax errors found
Alert level A PLAT029_ALERT_3_A _diffrn_measured_fraction_theta_full Low ....... 0.93
Author Response: Even though we collected data out to 0.84 \%A resolution, the crystal diffracted poorly beyond 0.88\%A resolution, where more than 50% of the missing data lie. Larger crystals were not obtainable, and since the crystals of this compound are no longer available, we can only rely on the current data set. |
Alert level C REFLT03_ALERT_3_C Reflection count < 95% complete From the CIF: _diffrn_reflns_theta_max 66.97 From the CIF: _diffrn_reflns_theta_full 66.97 From the CIF: _reflns_number_total 1662 TEST2: Reflns within _diffrn_reflns_theta_max Count of symmetry unique reflns 1785 Completeness (_total/calc) 93.11% PLAT022_ALERT_3_C Ratio Unique / Expected Reflections too Low .... 0.93 PLAT062_ALERT_4_C Rescale T(min) & T(max) by ..................... 1.03 PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........ 1
Alert level G PLAT793_ALERT_1_G Check the Absolute Configuration of C1 = ... S PLAT793_ALERT_1_G Check the Absolute Configuration of C8A = ... R
1 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 4 ALERT level C = Check and explain 2 ALERT level G = General alerts; check 2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 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 2 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
Compound (I) is previously unreported, although its ethyl ester has been described by Stork et al. (1963), whose procedure we used to prepare the analogous methyl ester, mp 330 K. Saponification, sublimation and crystallization from Et2O/hexane yielded crystals suitable for X-ray, mp 352 K. The C1/C8a stereochemistry clearly represents the stabler of the two epimers possible and probably arises from equilibrations during the alkylation or saponification steps (House et al., 1965).
The solid-state (KBr) infrared spectrum of (I) has C=O absorptions at 1723 & 1636 cm-1, with a peak separation typical of the shifts seen in catemers, due, respectively, to removal of H bonding from the acid C=O and addition of H bonding to the ketone; an alkene peak appears at 1616 cm-1. In CHCl3 solution, where dimers predominate, these bands appear, respectively, at 1713, 1667 and 1622 cm-1.
All H atoms for (I) were found in electron-density difference maps. The O—H was constrained to an idealized position with distance fixed at 0.84 Å and Uiso(H) = 1.5Ueq(O). The methylene, methine, and vinyl 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).
Among ketocarboxylic acids, we have shown that the normally dominant dimerization is disfavored by lowering molecular flexibility, as measured by the number of fully rotatable bonds present. Typically this results in an increased frequency of acid-to-ketone catemers, as in the title compound, (I), whose structure and H-bonding pattern we report here.
Fig. 1 shows the asymmetric unit, whose only conformational options lie in the carboxyl side-chain, which is turned [8a-C1—C9—O2 torsion angle = 20.11 (18)°] so as to avoid interaction with the equatorial H at C8.
The disordering of C—O bond lengths and C—C—O angles often seen in carboxyl dimers is not possible in H-bonding modes that preclude the averaging mechanisms involved. Because (I) is not dimeric the distances and angles here (Table 1) are typical of those in highly ordered dimeric carboxyls (Borthwick, 1980).
Fig. 2 shows the the acid-to-ketone H-bonding scheme. Each carboxylic acid is linked to the ketone in a molecule glide related in the c direction, creating H-bonding chains that advance at an angle to the cell axes. In all, four separate parallel chains pass through the cell in counterdirectional pairs related centrosymmetrically about 1/2, 1/2, 1/2. The intra-chain glide relationship found is considerably rarer than either screw or translational schemes generally, and is shared with three other γ-keto acids of our experience (Barcon et al., 1998, 2002; Dufort et al., 2007).
We characterize the geometry of H bonding to carbonyls using a combination of the H···O=C angle and the H···O=C—C torsional angle. These describe the approach of the H atom to the receptor O in terms of its deviation from, respectively, C=O axiality (ideal = 120°) and planarity with the carbonyl (ideal = 0°). In (I) these angles are 122 & -7°. Within the 2.6 Å range we standardly survey for C—H···O packing interactions (Steiner, 1997), one intermolecular close contact was found, involving C1 & O2 (Table 2).
For related literature, see: Barcon et al. (1998, 2002); Borthwick (1980); Dufort et al. (2007); House et al. (1965); Steiner (1997); Stork et al. (1963).
Data collection: APEX2 (Bruker, 2006); cell refinement: APEX2 (Bruker, 2006); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2004); program(s) used to refine structure: SHELXTL (Sheldrick, 2004); molecular graphics: SHELXTL Sheldrick, 2004); software used to prepare material for publication: SHELXTL (Sheldrick, 2004).
C11H14O3 | F(000) = 416 |
Mr = 194.22 | Dx = 1.287 Mg m−3 |
Monoclinic, P21/c | Melting point: 352 K |
Hall symbol: -P 2ybc | Cu Kα radiation, λ = 1.54178 Å |
a = 5.2691 (3) Å | Cell parameters from 5164 reflections |
b = 16.1279 (11) Å | θ = 4.6–67.0° |
c = 11.9181 (7) Å | µ = 0.76 mm−1 |
β = 98.252 (3)° | T = 100 K |
V = 1002.31 (11) Å3 | Parallelepiped, colourless |
Z = 4 | 0.38 × 0.36 × 0.16 mm |
Bruker APEXII CCD area-detector diffractometer | 1662 independent reflections |
Radiation source: fine-focus sealed tube | 1600 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.018 |
φ and ω scans | θmax = 67.0°, θmin = 4.6° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2001) | h = −5→6 |
Tmin = 0.78, Tmax = 0.86 | k = −18→18 |
5164 measured reflections | l = −13→13 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.036 | H-atom parameters constrained |
wR(F2) = 0.095 | w = 1/[σ2(Fo2) + (0.0434P)2 + 0.4766P] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max < 0.001 |
1662 reflections | Δρmax = 0.21 e Å−3 |
128 parameters | Δρmin = −0.21 e Å−3 |
0 restraints | Extinction correction: SHELXTL (Sheldrick, 2004), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0030 (7) |
C11H14O3 | V = 1002.31 (11) Å3 |
Mr = 194.22 | Z = 4 |
Monoclinic, P21/c | Cu Kα radiation |
a = 5.2691 (3) Å | µ = 0.76 mm−1 |
b = 16.1279 (11) Å | T = 100 K |
c = 11.9181 (7) Å | 0.38 × 0.36 × 0.16 mm |
β = 98.252 (3)° |
Bruker APEXII CCD area-detector diffractometer | 1662 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2001) | 1600 reflections with I > 2σ(I) |
Tmin = 0.78, Tmax = 0.86 | Rint = 0.018 |
5164 measured reflections |
R[F2 > 2σ(F2)] = 0.036 | 0 restraints |
wR(F2) = 0.095 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.21 e Å−3 |
1662 reflections | Δρmin = −0.21 e Å−3 |
128 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.4880 (2) | 0.16063 (8) | 0.05233 (11) | 0.0183 (3) | |
H1A | 0.6262 | 0.1271 | 0.0248 | 0.022* | |
O1 | 0.98255 (17) | 0.29981 (6) | 0.18075 (8) | 0.0224 (3) | |
C2 | 0.5929 (2) | 0.24841 (8) | 0.07921 (11) | 0.0199 (3) | |
H2A | 0.6534 | 0.2720 | 0.0111 | 0.024* | |
H2B | 0.4536 | 0.2843 | 0.0991 | 0.024* | |
O2 | 0.04242 (18) | 0.16180 (7) | −0.03204 (9) | 0.0297 (3) | |
C3 | 0.8103 (2) | 0.24758 (8) | 0.17578 (11) | 0.0189 (3) | |
O3 | 0.34570 (18) | 0.18208 (6) | −0.14192 (8) | 0.0254 (3) | |
H3A | 0.2185 | 0.1869 | −0.1928 | 0.038* | |
C4 | 0.7986 (3) | 0.18636 (8) | 0.26462 (12) | 0.0210 (3) | |
H4A | 0.9289 | 0.1866 | 0.3286 | 0.025* | |
C4A | 0.6117 (3) | 0.12961 (8) | 0.25999 (11) | 0.0206 (3) | |
C5 | 0.5812 (3) | 0.07688 (9) | 0.36134 (12) | 0.0264 (3) | |
H5A | 0.4392 | 0.0995 | 0.3982 | 0.032* | |
H5B | 0.7401 | 0.0806 | 0.4166 | 0.032* | |
C6 | 0.5259 (3) | −0.01464 (9) | 0.33257 (12) | 0.0287 (4) | |
H6A | 0.6802 | −0.0408 | 0.3094 | 0.034* | |
H6B | 0.4843 | −0.0440 | 0.4006 | 0.034* | |
C7 | 0.3024 (3) | −0.02239 (9) | 0.23702 (13) | 0.0285 (4) | |
H7A | 0.2720 | −0.0816 | 0.2175 | 0.034* | |
H7B | 0.1450 | 0.0003 | 0.2619 | 0.034* | |
C8A | 0.4120 (2) | 0.11763 (8) | 0.15658 (11) | 0.0194 (3) | |
H8AA | 0.2484 | 0.1433 | 0.1730 | 0.023* | |
C8 | 0.3614 (3) | 0.02474 (9) | 0.13348 (12) | 0.0239 (3) | |
H8A | 0.2152 | 0.0187 | 0.0719 | 0.029* | |
H8B | 0.5140 | −0.0002 | 0.1071 | 0.029* | |
C9 | 0.2656 (2) | 0.16697 (8) | −0.04338 (12) | 0.0192 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0169 (6) | 0.0171 (7) | 0.0206 (7) | 0.0001 (5) | 0.0023 (5) | −0.0003 (5) |
O1 | 0.0222 (5) | 0.0197 (5) | 0.0244 (5) | −0.0035 (4) | 0.0005 (4) | −0.0018 (4) |
C2 | 0.0201 (7) | 0.0171 (7) | 0.0220 (7) | 0.0001 (5) | 0.0015 (5) | 0.0020 (5) |
O2 | 0.0170 (5) | 0.0446 (7) | 0.0273 (6) | −0.0026 (4) | 0.0021 (4) | 0.0028 (5) |
C3 | 0.0194 (7) | 0.0163 (6) | 0.0212 (7) | 0.0024 (5) | 0.0037 (5) | −0.0039 (5) |
O3 | 0.0191 (5) | 0.0369 (6) | 0.0196 (5) | 0.0013 (4) | 0.0004 (4) | 0.0053 (4) |
C4 | 0.0225 (7) | 0.0202 (7) | 0.0192 (7) | 0.0023 (5) | −0.0009 (5) | −0.0019 (5) |
C4A | 0.0254 (7) | 0.0175 (7) | 0.0192 (7) | 0.0039 (5) | 0.0050 (5) | −0.0019 (5) |
C5 | 0.0368 (8) | 0.0226 (7) | 0.0200 (7) | −0.0022 (6) | 0.0047 (6) | 0.0004 (6) |
C6 | 0.0427 (9) | 0.0201 (7) | 0.0245 (8) | −0.0021 (6) | 0.0089 (7) | 0.0037 (6) |
C7 | 0.0355 (8) | 0.0218 (7) | 0.0297 (8) | −0.0067 (6) | 0.0099 (6) | 0.0006 (6) |
C8A | 0.0183 (6) | 0.0181 (7) | 0.0220 (7) | −0.0001 (5) | 0.0037 (5) | −0.0002 (5) |
C8 | 0.0277 (7) | 0.0195 (7) | 0.0242 (7) | −0.0049 (5) | 0.0025 (6) | −0.0012 (6) |
C9 | 0.0199 (7) | 0.0143 (6) | 0.0233 (7) | −0.0001 (5) | 0.0027 (5) | −0.0011 (5) |
C1—C9 | 1.5171 (18) | C4A—C8A | 1.5138 (19) |
C1—C8A | 1.5258 (18) | C5—C6 | 1.5337 (19) |
C1—C2 | 1.5367 (18) | C5—H5A | 0.9900 |
C1—H1A | 1.0000 | C5—H5B | 0.9900 |
O1—C3 | 1.2335 (16) | C6—C7 | 1.521 (2) |
C2—C3 | 1.5028 (18) | C6—H6A | 0.9900 |
C2—H2A | 0.9900 | C6—H6B | 0.9900 |
C2—H2B | 0.9900 | C7—C8 | 1.519 (2) |
O2—C9 | 1.2056 (16) | C7—H7A | 0.9900 |
C3—C4 | 1.4555 (19) | C7—H7B | 0.9900 |
O3—C9 | 1.3263 (17) | C8A—C8 | 1.5395 (18) |
O3—H3A | 0.8400 | C8A—H8AA | 1.0000 |
C4—C4A | 1.340 (2) | C8—H8A | 0.9900 |
C4—H4A | 0.9500 | C8—H8B | 0.9900 |
C4A—C5 | 1.5046 (19) | ||
C9—C1—C8A | 112.21 (10) | C7—C6—C5 | 110.39 (12) |
C9—C1—C2 | 108.09 (10) | C7—C6—H6A | 109.6 |
C8A—C1—C2 | 112.19 (11) | C5—C6—H6A | 109.6 |
C9—C1—H1A | 108.1 | C7—C6—H6B | 109.6 |
C8A—C1—H1A | 108.1 | C5—C6—H6B | 109.6 |
C2—C1—H1A | 108.1 | H6A—C6—H6B | 108.1 |
C3—C2—C1 | 111.30 (10) | C8—C7—C6 | 109.89 (11) |
C3—C2—H2A | 109.4 | C8—C7—H7A | 109.7 |
C1—C2—H2A | 109.4 | C6—C7—H7A | 109.7 |
C3—C2—H2B | 109.4 | C8—C7—H7B | 109.7 |
C1—C2—H2B | 109.4 | C6—C7—H7B | 109.7 |
H2A—C2—H2B | 108.0 | H7A—C7—H7B | 108.2 |
O1—C3—C4 | 122.42 (12) | C4A—C8A—C1 | 111.82 (11) |
O1—C3—C2 | 120.36 (12) | C4A—C8A—C8 | 110.61 (11) |
C4—C3—C2 | 117.12 (11) | C1—C8A—C8 | 110.83 (11) |
C9—O3—H3A | 109.5 | C4A—C8A—H8AA | 107.8 |
C4A—C4—C3 | 122.76 (12) | C1—C8A—H8AA | 107.8 |
C4A—C4—H4A | 118.6 | C8—C8A—H8AA | 107.8 |
C3—C4—H4A | 118.6 | C7—C8—C8A | 113.08 (12) |
C4—C4A—C5 | 121.04 (13) | C7—C8—H8A | 109.0 |
C4—C4A—C8A | 122.81 (12) | C8A—C8—H8A | 109.0 |
C5—C4A—C8A | 116.08 (12) | C7—C8—H8B | 109.0 |
C4A—C5—C6 | 113.78 (12) | C8A—C8—H8B | 109.0 |
C4A—C5—H5A | 108.8 | H8A—C8—H8B | 107.8 |
C6—C5—H5A | 108.8 | O2—C9—O3 | 123.47 (12) |
C4A—C5—H5B | 108.8 | O2—C9—C1 | 124.87 (12) |
C6—C5—H5B | 108.8 | O3—C9—C1 | 111.62 (11) |
H5A—C5—H5B | 107.7 | ||
C9—C1—C2—C3 | 178.46 (10) | C4—C4A—C8A—C8 | 138.44 (13) |
C8A—C1—C2—C3 | 54.22 (14) | C5—C4A—C8A—C8 | −44.76 (16) |
C1—C2—C3—O1 | 149.92 (12) | C9—C1—C8A—C4A | −166.25 (10) |
C1—C2—C3—C4 | −33.63 (15) | C2—C1—C8A—C4A | −44.33 (14) |
O1—C3—C4—C4A | 179.79 (12) | C9—C1—C8A—C8 | 69.82 (14) |
C2—C3—C4—C4A | 3.41 (19) | C2—C1—C8A—C8 | −168.25 (11) |
C3—C4—C4A—C5 | −169.72 (12) | C6—C7—C8—C8A | −59.22 (16) |
C3—C4—C4A—C8A | 6.9 (2) | C4A—C8A—C8—C7 | 51.49 (15) |
C4—C4A—C5—C6 | −137.03 (14) | C1—C8A—C8—C7 | 176.11 (11) |
C8A—C4A—C5—C6 | 46.11 (17) | C8A—C1—C9—O2 | 20.11 (18) |
C4A—C5—C6—C7 | −51.45 (17) | C2—C1—C9—O2 | −104.11 (15) |
C5—C6—C7—C8 | 57.55 (16) | C8A—C1—C9—O3 | −162.19 (11) |
C4—C4A—C8A—C1 | 14.39 (18) | C2—C1—C9—O3 | 73.59 (13) |
C5—C4A—C8A—C1 | −168.81 (11) |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3A···O1i | 0.84 | 1.82 | 2.6557 (13) | 170 |
C1—H1A···O2ii | 1.00 | 2.45 | 3.2230 (15) | 134 |
Symmetry codes: (i) x−1, −y+1/2, z−1/2; (ii) x+1, y, z. |
Experimental details
Crystal data | |
Chemical formula | C11H14O3 |
Mr | 194.22 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 100 |
a, b, c (Å) | 5.2691 (3), 16.1279 (11), 11.9181 (7) |
β (°) | 98.252 (3) |
V (Å3) | 1002.31 (11) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 0.76 |
Crystal size (mm) | 0.38 × 0.36 × 0.16 |
Data collection | |
Diffractometer | Bruker APEXII CCD area-detector |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2001) |
Tmin, Tmax | 0.78, 0.86 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5164, 1662, 1600 |
Rint | 0.018 |
(sin θ/λ)max (Å−1) | 0.597 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.036, 0.095, 1.08 |
No. of reflections | 1662 |
No. of parameters | 128 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.21, −0.21 |
Computer programs: APEX2 (Bruker, 2006), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2004), SHELXTL Sheldrick, 2004).
O2—C9 | 1.2056 (16) | O3—C9 | 1.3263 (17) |
O2—C9—C1 | 124.87 (12) | O3—C9—C1 | 111.62 (11) |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3A···O1i | 0.84 | 1.82 | 2.6557 (13) | 170 |
C1—H1A···O2ii | 1.00 | 2.45 | 3.2230 (15) | 134 |
Symmetry codes: (i) x−1, −y+1/2, z−1/2; (ii) x+1, y, z. |
Among ketocarboxylic acids, we have shown that the normally dominant dimerization is disfavored by lowering molecular flexibility, as measured by the number of fully rotatable bonds present. Typically this results in an increased frequency of acid-to-ketone catemers, as in the title compound, (I), whose structure and H-bonding pattern we report here.
Fig. 1 shows the asymmetric unit, whose only conformational options lie in the carboxyl side-chain, which is turned [8a-C1—C9—O2 torsion angle = 20.11 (18)°] so as to avoid interaction with the equatorial H at C8.
The disordering of C—O bond lengths and C—C—O angles often seen in carboxyl dimers is not possible in H-bonding modes that preclude the averaging mechanisms involved. Because (I) is not dimeric the distances and angles here (Table 1) are typical of those in highly ordered dimeric carboxyls (Borthwick, 1980).
Fig. 2 shows the the acid-to-ketone H-bonding scheme. Each carboxylic acid is linked to the ketone in a molecule glide related in the c direction, creating H-bonding chains that advance at an angle to the cell axes. In all, four separate parallel chains pass through the cell in counterdirectional pairs related centrosymmetrically about 1/2, 1/2, 1/2. The intra-chain glide relationship found is considerably rarer than either screw or translational schemes generally, and is shared with three other γ-keto acids of our experience (Barcon et al., 1998, 2002; Dufort et al., 2007).
We characterize the geometry of H bonding to carbonyls using a combination of the H···O=C angle and the H···O=C—C torsional angle. These describe the approach of the H atom to the receptor O in terms of its deviation from, respectively, C=O axiality (ideal = 120°) and planarity with the carbonyl (ideal = 0°). In (I) these angles are 122 & -7°. Within the 2.6 Å range we standardly survey for C—H···O packing interactions (Steiner, 1997), one intermolecular close contact was found, involving C1 & O2 (Table 2).