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A metastable modification of (RS)-mandelic acid, C8H8O3, was obtained from an aqueous solution. The structure features hydrogen-bonded double chains of acid molecules, which run along the a axis of the crystal. The structure shows a close relationship to that of the pure enantiomer and differs significantly from the structure of the stable modification of the racemate. There are two molecules in the asymmetric unit.
Supporting information
CCDC reference: 221677
Key indicators
- Single-crystal X-ray study
- T = 299 K
- Mean (C-C) = 0.003 Å
- R factor = 0.049
- wR factor = 0.149
- Data-to-parameter ratio = 13.0
checkCIF results
No syntax errors found
ADDSYM reports no extra symmetry
Data collection: Bruker–Nonius KappaCCD; cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2001); software used to prepare material for publication: maXus (Mackay et al., 1997).
Crystal data top
C8H8O3 | F(000) = 640 |
Mr = 152.15 | Dx = 1.356 Mg m−3 |
Monoclinic, P21/c | Cu Kα radiation, λ = 1.54180 Å |
Hall symbol: -P 2ybc | Cell parameters from 7612 reflections |
a = 5.8468 (1) Å | θ = 6.8–66.5° |
b = 29.2410 (4) Å | µ = 0.88 mm−1 |
c = 8.7228 (1) Å | T = 299 K |
β = 92.1651 (8)° | Prism, colourless |
V = 1490.24 (4) Å3 | 0.30 × 0.30 × 0.10 mm |
Z = 8 | |
Data collection top
Bruker–Nonius KappaCCD diffractometer | 1884 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.048 |
φ and ω scans | θmax = 66.5°, θmin = 6.8° |
Absorption correction: numerical Herrendorf & Bärnighausen, 1997 | h = −6→6 |
Tmin = 0.741, Tmax = 0.938 | k = −34→34 |
10243 measured reflections | l = −10→9 |
2590 independent reflections | |
Refinement top
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)] = 0.049 | H-atom parameters constrained |
wR(F2) = 0.149 | w = 1/[σ2(Fo2) + (0.0769P)2 + 0.286P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max < 0.001 |
2590 reflections | Δρmax = 0.14 e Å−3 |
199 parameters | Δρmin = −0.21 e Å−3 |
0 restraints | |
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 | 0.2808 (3) | 0.05269 (5) | 0.33403 (19) | 0.0399 (4) | |
C2 | 0.5055 (3) | 0.06902 (6) | 0.2714 (2) | 0.0412 (4) | |
C3 | 0.5255 (3) | 0.12047 (6) | 0.27204 (19) | 0.0411 (4) | |
C4 | 0.4536 (4) | 0.14595 (6) | 0.3947 (2) | 0.0585 (5) | |
C5 | 0.4767 (4) | 0.19325 (7) | 0.3950 (3) | 0.0724 (7) | |
C6 | 0.5738 (4) | 0.21487 (7) | 0.2758 (3) | 0.0696 (6) | |
C7 | 0.6466 (4) | 0.19035 (7) | 0.1543 (3) | 0.0766 (7) | |
C8 | 0.6227 (4) | 0.14295 (6) | 0.1516 (2) | 0.0608 (6) | |
C9 | 0.7778 (3) | 0.05135 (5) | 0.8320 (2) | 0.0409 (4) | |
C10 | 1.0020 (3) | 0.06598 (6) | 0.7642 (2) | 0.0438 (4) | |
C11 | 1.0277 (3) | 0.11732 (6) | 0.7660 (2) | 0.0423 (4) | |
C12 | 1.1151 (4) | 0.13965 (7) | 0.8940 (2) | 0.0605 (5) | |
C13 | 1.1369 (4) | 0.18708 (7) | 0.8939 (3) | 0.0761 (7) | |
C14 | 1.0699 (4) | 0.21181 (7) | 0.7685 (3) | 0.0750 (7) | |
C15 | 0.9812 (4) | 0.19021 (7) | 0.6406 (3) | 0.0736 (7) | |
C16 | 0.9607 (4) | 0.14299 (6) | 0.6381 (2) | 0.0587 (5) | |
O1 | 0.1026 (2) | 0.06905 (5) | 0.25626 (16) | 0.0583 (4) | |
O2 | 0.2690 (2) | 0.02713 (4) | 0.44106 (16) | 0.0569 (4) | |
O3 | 0.6929 (2) | 0.05020 (4) | 0.35972 (15) | 0.0545 (4) | |
O4 | 0.5990 (2) | 0.06828 (5) | 0.75698 (16) | 0.0614 (4) | |
O5 | 0.7677 (2) | 0.02675 (5) | 0.94136 (16) | 0.0606 (4) | |
O6 | 1.1878 (2) | 0.04496 (4) | 0.84534 (17) | 0.0607 (4) | |
H2 | 0.5035 | 0.0574 | 0.1631 | 0.049* | |
H4 | 0.3851 | 0.1272 | 0.4973 | 0.070* | |
H5 | 0.4128 | 0.2107 | 0.5016 | 0.087* | |
H6 | 0.5852 | 0.2508 | 0.2770 | 0.084* | |
H7 | 0.7184 | 0.2063 | 0.0467 | 0.092* | |
H8 | 0.6838 | 0.1213 | 0.0529 | 0.073* | |
H10 | 1.0022 | 0.0551 | 0.6621 | 0.053* | |
H12 | 1.1643 | 0.1204 | 0.9989 | 0.073* | |
H13 | 1.1983 | 0.2031 | 1.0101 | 0.091* | |
H14 | 1.0854 | 0.2498 | 0.7785 | 0.090* | |
H15 | 0.9224 | 0.2070 | 0.5326 | 0.088* | |
H16 | 0.8876 | 0.1227 | 0.5380 | 0.070* | |
H1O | −0.0607 | 0.0579 | 0.2959 | 0.070* | |
H3O | 0.6532 | 0.0231 | 0.4101 | 0.065* | |
H4O | 0.4497 | 0.0588 | 0.8108 | 0.074* | |
H6O | 1.1548 | 0.0221 | 0.9281 | 0.073* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C1 | 0.0297 (9) | 0.0385 (8) | 0.0516 (10) | 0.0005 (6) | 0.0021 (7) | 0.0002 (7) |
C2 | 0.0289 (9) | 0.0448 (9) | 0.0501 (10) | 0.0017 (7) | 0.0040 (7) | 0.0037 (7) |
C3 | 0.0285 (9) | 0.0438 (9) | 0.0508 (10) | 0.0000 (7) | 0.0002 (7) | 0.0041 (7) |
C4 | 0.0616 (13) | 0.0504 (11) | 0.0641 (12) | −0.0002 (9) | 0.0111 (10) | −0.0011 (9) |
C5 | 0.0729 (16) | 0.0510 (12) | 0.0938 (17) | 0.0016 (10) | 0.0087 (13) | −0.0115 (11) |
C6 | 0.0566 (14) | 0.0463 (11) | 0.1059 (19) | −0.0029 (9) | 0.0032 (13) | 0.0075 (12) |
C7 | 0.0797 (17) | 0.0567 (12) | 0.0943 (17) | −0.0100 (11) | 0.0143 (14) | 0.0215 (12) |
C8 | 0.0638 (14) | 0.0559 (11) | 0.0638 (12) | −0.0062 (10) | 0.0159 (10) | 0.0090 (9) |
C9 | 0.0311 (10) | 0.0388 (8) | 0.0531 (10) | −0.0002 (7) | 0.0046 (7) | −0.0011 (8) |
C10 | 0.0287 (9) | 0.0476 (10) | 0.0555 (10) | 0.0021 (7) | 0.0063 (7) | 0.0024 (8) |
C11 | 0.0282 (9) | 0.0462 (9) | 0.0526 (10) | −0.0018 (7) | 0.0042 (7) | 0.0046 (8) |
C12 | 0.0590 (13) | 0.0600 (11) | 0.0617 (12) | −0.0059 (10) | −0.0070 (10) | −0.0004 (9) |
C13 | 0.0713 (16) | 0.0599 (13) | 0.0963 (17) | −0.0088 (11) | −0.0084 (13) | −0.0154 (12) |
C14 | 0.0571 (14) | 0.0511 (11) | 0.117 (2) | −0.0031 (10) | −0.0004 (14) | 0.0062 (12) |
C15 | 0.0712 (16) | 0.0591 (13) | 0.0903 (16) | 0.0030 (11) | −0.0013 (13) | 0.0235 (12) |
C16 | 0.0553 (13) | 0.0589 (11) | 0.0614 (12) | −0.0007 (9) | −0.0028 (9) | 0.0101 (9) |
O1 | 0.0307 (7) | 0.0738 (9) | 0.0700 (9) | −0.0004 (6) | −0.0019 (6) | 0.0190 (7) |
O2 | 0.0374 (8) | 0.0598 (8) | 0.0739 (9) | 0.0010 (6) | 0.0068 (6) | 0.0231 (7) |
O3 | 0.0288 (7) | 0.0513 (7) | 0.0835 (10) | 0.0034 (5) | 0.0038 (6) | 0.0198 (6) |
O4 | 0.0305 (7) | 0.0804 (9) | 0.0734 (9) | −0.0001 (6) | 0.0023 (6) | 0.0213 (7) |
O5 | 0.0381 (8) | 0.0650 (8) | 0.0793 (9) | 0.0017 (6) | 0.0092 (6) | 0.0246 (7) |
O6 | 0.0296 (7) | 0.0603 (8) | 0.0926 (10) | 0.0051 (6) | 0.0080 (6) | 0.0260 (7) |
Geometric parameters (Å, º) top
C1—O2 | 1.200 (2) | C13—C14 | 1.357 (3) |
C1—O1 | 1.312 (2) | C14—C15 | 1.368 (3) |
C1—C2 | 1.519 (2) | C15—C16 | 1.386 (3) |
C2—O3 | 1.426 (2) | C2—H2 | 1.0035 |
C2—C3 | 1.509 (2) | C4—H4 | 1.1347 |
C3—C8 | 1.380 (3) | C5—H5 | 1.1356 |
C3—C4 | 1.382 (3) | C6—H6 | 1.0512 |
C4—C5 | 1.390 (3) | C7—H7 | 1.1416 |
C5—C6 | 1.359 (3) | C8—H8 | 1.1377 |
C6—C7 | 1.362 (3) | C10—H10 | 0.9461 |
C7—C8 | 1.393 (3) | C12—H12 | 1.1040 |
C9—O5 | 1.198 (2) | C13—H13 | 1.1610 |
C9—O4 | 1.309 (2) | C14—H14 | 1.1180 |
C9—C10 | 1.519 (2) | C15—H15 | 1.1058 |
C10—O6 | 1.414 (2) | C16—H16 | 1.1267 |
C10—C11 | 1.509 (2) | O1—H1O | 1.0784 |
C11—C12 | 1.375 (3) | O3—H3O | 0.9396 |
C11—C16 | 1.389 (3) | O4—H4O | 1.0444 |
C12—C13 | 1.393 (3) | O6—H6O | 1.0088 |
| | | |
O2—C1—O1 | 124.18 (15) | C3—C2—H2 | 109.8 |
O2—C1—C2 | 123.48 (15) | C1—C2—H2 | 104.7 |
O1—C1—C2 | 112.33 (14) | C3—C4—H4 | 118.5 |
O3—C2—C3 | 108.97 (13) | C5—C4—H4 | 121.0 |
O3—C2—C1 | 109.96 (13) | C6—C5—H5 | 125.3 |
C3—C2—C1 | 112.33 (14) | C4—C5—H5 | 114.4 |
C8—C3—C4 | 118.59 (17) | C5—C6—H6 | 119.0 |
C8—C3—C2 | 120.40 (16) | C7—C6—H6 | 120.7 |
C4—C3—C2 | 120.98 (16) | C6—C7—H7 | 124.1 |
C3—C4—C5 | 120.4 (2) | C8—C7—H7 | 115.5 |
C6—C5—C4 | 120.3 (2) | C3—C8—H8 | 117.4 |
C5—C6—C7 | 120.2 (2) | C7—C8—H8 | 122.3 |
C6—C7—C8 | 120.2 (2) | O6—C10—H10 | 107.2 |
C3—C8—C7 | 120.3 (2) | C11—C10—H10 | 109.9 |
O5—C9—O4 | 124.24 (16) | C9—C10—H10 | 107.7 |
O5—C9—C10 | 123.24 (15) | C11—C12—H12 | 120.5 |
O4—C9—C10 | 112.51 (15) | C13—C12—H12 | 119.2 |
O6—C10—C11 | 110.68 (14) | C14—C13—H13 | 124.0 |
O6—C10—C9 | 109.90 (14) | C12—C13—H13 | 115.2 |
C11—C10—C9 | 111.30 (14) | C13—C14—H14 | 116.5 |
C12—C11—C16 | 118.73 (17) | C15—C14—H14 | 123.4 |
C12—C11—C10 | 120.96 (16) | C14—C15—H15 | 125.9 |
C16—C11—C10 | 120.31 (16) | C16—C15—H15 | 113.9 |
C11—C12—C13 | 120.24 (19) | C15—C16—H16 | 124.5 |
C14—C13—C12 | 120.5 (2) | C11—C16—H16 | 115.2 |
C13—C14—C15 | 120.1 (2) | C1—O1—H1O | 114.8 |
C14—C15—C16 | 120.2 (2) | C2—O3—H3O | 112.3 |
C15—C16—C11 | 120.29 (19) | C9—O4—H4O | 109.9 |
O3—C2—H2 | 111.1 | C10—O6—H6O | 118.9 |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1O···O3i | 1.08 | 1.58 | 2.6492 (18) | 170 |
O3—H3O···O2ii | 0.94 | 2.00 | 2.8557 (16) | 150 |
O4—H4O···O6i | 1.04 | 1.62 | 2.6419 (18) | 164 |
O6—H6O···O5iii | 1.01 | 1.87 | 2.8089 (17) | 153 |
Symmetry codes: (i) x−1, y, z; (ii) −x+1, −y, −z+1; (iii) −x+2, −y, −z+2. |
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