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2-Methoxy-2-phenylacetic acid, C9H10O3, forms helical columns of single enantiomers linked by hydrogen bonding between the acidic proton of one molecule and the methoxy O atom of a neighbouring molecule, to give an overall racemic structure.
Supporting information
CCDC reference: 232161
Key indicators
- Single-crystal X-ray study
- T = 299 K
- Mean (C-C) = 0.004 Å
- R factor = 0.055
- wR factor = 0.174
- Data-to-parameter ratio = 13.0
checkCIF/PLATON results
No syntax errors found
Alert level C
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given ....... ?
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
1 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
0 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
0 ALERT type 3 Indicator that the structure quality may be low
1 ALERT type 4 Improvement, methodology, query or suggestion
Data collection: CrysAlis CCD (Oxford Diffraction, 2001); cell refinement: CrysAlis RED (Oxford Diffraction, 2001); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON2002 (Spek, 2002); software used to prepare material for publication: SHELXL97.
2-Methoxy-2-phenylacetic acid
top
Crystal data top
C9H10O3 | Dx = 1.335 Mg m−3 |
Mr = 166.17 | Melting point = 342–344 K |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 10.093 (3) Å | Cell parameters from 877 reflections |
b = 7.123 (2) Å | θ = 3.3–20.9° |
c = 12.270 (3) Å | µ = 0.10 mm−1 |
β = 110.40 (1)° | T = 299 K |
V = 826.8 (4) Å3 | Prism, colourless |
Z = 4 | 0.60 × 0.48 × 0.16 mm |
F(000) = 352 | |
Data collection top
Oxford Diffraction Xcalibur CCD diffractometer | 994 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.035 |
Graphite monochromator | θmax = 26.4°, θmin = 4.3° |
Detector resolution: Sapphire CCD detector pixels mm-1 | h = −12→12 |
Rotation method data acquisition using ω scans | k = −8→8 |
4076 measured reflections | l = −15→8 |
1665 independent reflections | |
Refinement top
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)] = 0.055 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.174 | w = 1/[σ2(Fo2) + (0.1149P)2] where P = (Fo2 + 2Fc2)/3 |
S = 0.88 | (Δ/σ)max = 0.045 |
1665 reflections | Δρmax = 0.25 e Å−3 |
128 parameters | Δρmin = −0.23 e Å−3 |
0 restraints | Extinction correction: SHELXL97 and Larson (1970), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.051 (11) |
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 | x | y | z | Uiso*/Ueq | |
C1 | 0.7339 (3) | 0.2807 (3) | 0.8075 (2) | 0.0435 (6) | |
C2 | 0.7180 (3) | 0.1526 (3) | 0.90045 (18) | 0.0406 (6) | |
H2 | 0.6314 | 0.0784 | 0.8676 | 0.049* | |
C3 | 0.7100 (3) | 0.2644 (3) | 1.00170 (18) | 0.0383 (6) | |
C4 | 0.5909 (3) | 0.2602 (4) | 1.0316 (2) | 0.0482 (7) | |
H4 | 0.516 (3) | 0.180 (4) | 0.991 (2) | 0.058* | |
C5 | 0.5848 (4) | 0.3663 (4) | 1.1237 (2) | 0.0590 (8) | |
H5 | 0.500 (3) | 0.362 (4) | 1.140 (3) | 0.071* | |
C6 | 0.6954 (4) | 0.4765 (4) | 1.1850 (2) | 0.0598 (9) | |
H6 | 0.685 (3) | 0.555 (4) | 1.248 (3) | 0.072* | |
C7 | 0.8143 (4) | 0.4805 (4) | 1.1567 (2) | 0.0577 (8) | |
H7 | 0.892 (3) | 0.559 (4) | 1.197 (2) | 0.069* | |
C8 | 0.8218 (3) | 0.3738 (4) | 1.0657 (2) | 0.0501 (7) | |
H8 | 0.899 (3) | 0.380 (4) | 1.045 (2) | 0.060* | |
C9 | 0.8223 (3) | −0.1216 (3) | 1.0022 (2) | 0.0543 (8) | |
H9A | 0.7414 | −0.1956 | 0.9595 | 0.065* | |
H9B | 0.8108 | −0.0745 | 1.0717 | 0.065* | |
H9C | 0.9057 | −0.1981 | 1.0227 | 0.065* | |
O1 | 0.6155 (2) | 0.3658 (3) | 0.75018 (15) | 0.0576 (6) | |
H1O | 0.637 (3) | 0.442 (4) | 0.700 (3) | 0.069* | |
O2 | 0.8413 (2) | 0.3008 (3) | 0.78952 (17) | 0.0765 (8) | |
O3 | 0.83571 (17) | 0.0315 (2) | 0.93238 (13) | 0.0443 (5) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C1 | 0.0482 (16) | 0.0471 (14) | 0.0372 (12) | −0.0001 (12) | 0.0175 (11) | 0.0026 (11) |
C2 | 0.0431 (15) | 0.0417 (13) | 0.0398 (12) | −0.0017 (11) | 0.0179 (11) | 0.0004 (10) |
C3 | 0.0497 (15) | 0.0345 (12) | 0.0347 (11) | 0.0029 (11) | 0.0197 (11) | 0.0051 (10) |
C4 | 0.0564 (18) | 0.0458 (14) | 0.0487 (14) | 0.0032 (13) | 0.0263 (13) | 0.0071 (12) |
C5 | 0.073 (2) | 0.0583 (17) | 0.0619 (16) | 0.0150 (16) | 0.0442 (16) | 0.0109 (15) |
C6 | 0.096 (3) | 0.0469 (16) | 0.0440 (14) | 0.0132 (16) | 0.0333 (16) | 0.0007 (12) |
C7 | 0.078 (2) | 0.0479 (16) | 0.0437 (14) | −0.0015 (14) | 0.0169 (14) | −0.0055 (12) |
C8 | 0.0551 (18) | 0.0533 (15) | 0.0460 (13) | −0.0023 (13) | 0.0228 (12) | −0.0020 (12) |
C9 | 0.070 (2) | 0.0479 (15) | 0.0507 (14) | 0.0064 (13) | 0.0275 (13) | 0.0123 (12) |
O1 | 0.0569 (13) | 0.0685 (13) | 0.0525 (10) | 0.0106 (10) | 0.0255 (9) | 0.0218 (9) |
O2 | 0.0549 (14) | 0.1081 (18) | 0.0738 (13) | 0.0062 (12) | 0.0317 (11) | 0.0421 (12) |
O3 | 0.0531 (12) | 0.0416 (9) | 0.0426 (9) | 0.0036 (8) | 0.0222 (8) | 0.0011 (7) |
Geometric parameters (Å, º) top
C1—O2 | 1.187 (3) | C5—H5 | 0.94 (3) |
C1—O1 | 1.306 (3) | C6—C7 | 1.361 (4) |
C1—C2 | 1.512 (3) | C6—H6 | 0.99 (3) |
C2—O3 | 1.408 (3) | C7—C8 | 1.373 (4) |
C2—C3 | 1.502 (3) | C7—H7 | 0.95 (3) |
C2—H2 | 0.9800 | C8—H8 | 0.90 (3) |
C3—C8 | 1.371 (4) | C9—O3 | 1.422 (3) |
C3—C4 | 1.374 (3) | C9—H9A | 0.9600 |
C4—C5 | 1.379 (4) | C9—H9B | 0.9600 |
C4—H4 | 0.94 (3) | C9—H9C | 0.9600 |
C5—C6 | 1.357 (4) | O1—H1O | 0.90 (3) |
| | | |
O2—C1—O1 | 124.6 (2) | C5—C6—C7 | 119.9 (3) |
O2—C1—C2 | 123.8 (2) | C5—C6—H6 | 117.9 (17) |
O1—C1—C2 | 111.6 (2) | C7—C6—H6 | 122.1 (17) |
O3—C2—C3 | 112.23 (18) | C6—C7—C8 | 119.9 (3) |
O3—C2—C1 | 106.16 (18) | C6—C7—H7 | 121.7 (17) |
C3—C2—C1 | 110.75 (19) | C8—C7—H7 | 118.4 (17) |
O3—C2—H2 | 109.2 | C3—C8—C7 | 120.8 (3) |
C3—C2—H2 | 109.2 | C3—C8—H8 | 119.2 (18) |
C1—C2—H2 | 109.2 | C7—C8—H8 | 119.9 (18) |
C8—C3—C4 | 118.8 (2) | O3—C9—H9A | 109.5 |
C8—C3—C2 | 120.3 (2) | O3—C9—H9B | 109.5 |
C4—C3—C2 | 120.9 (2) | H9A—C9—H9B | 109.5 |
C3—C4—C5 | 120.0 (3) | O3—C9—H9C | 109.5 |
C3—C4—H4 | 119.4 (16) | H9A—C9—H9C | 109.5 |
C5—C4—H4 | 120.5 (16) | H9B—C9—H9C | 109.5 |
C6—C5—C4 | 120.5 (3) | C1—O1—H1O | 104.9 (18) |
C6—C5—H5 | 122.2 (18) | C2—O3—C9 | 112.89 (17) |
C4—C5—H5 | 117.3 (19) | | |
| | | |
O2—C1—C2—O3 | −16.5 (3) | C2—C3—C4—C5 | −179.0 (2) |
O1—C1—C2—O3 | 163.59 (19) | C3—C4—C5—C6 | 0.5 (4) |
O2—C1—C2—C3 | 105.6 (3) | C4—C5—C6—C7 | −1.0 (4) |
O1—C1—C2—C3 | −74.3 (3) | C5—C6—C7—C8 | 0.4 (4) |
O3—C2—C3—C8 | 55.9 (3) | C4—C3—C8—C7 | −1.3 (4) |
C1—C2—C3—C8 | −62.5 (3) | C2—C3—C8—C7 | 178.3 (2) |
O3—C2—C3—C4 | −124.5 (2) | C6—C7—C8—C3 | 0.8 (4) |
C1—C2—C3—C4 | 117.1 (2) | C3—C2—O3—C9 | 70.6 (2) |
C8—C3—C4—C5 | 0.7 (4) | C1—C2—O3—C9 | −168.23 (18) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1O···O3i | 0.90 (3) | 1.85 (3) | 2.725 (2) | 162 (3) |
O1—H1O···O2i | 0.90 (3) | 2.57 (3) | 3.190 (3) | 127 (2) |
Symmetry code: (i) −x+3/2, y+1/2, −z+3/2. |
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