The skeleton of the title compound, C
9H
6O
4·0.5H
2O, with the water molecule located on a twofold rotation axis, consists of a coumarin that is composed of a benzene ring and a lactone ring. The hydroxyl groups, carbonyl group and water form intermolecular O—H
O hydrogen bonds, which link the molecules and solvent water into a three-dimensional network. An error in the position of an H atom in the original report is corrected.
Supporting information
CCDC reference: 627283
Key indicators
- Single-crystal X-ray study
- T = 298 K
- Mean (C-C) = 0.003 Å
- R factor = 0.043
- wR factor = 0.110
- Data-to-parameter ratio = 8.0
checkCIF/PLATON results
No syntax errors found
Alert level C
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings Differ .... ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ .... ?
PLAT045_ALERT_1_C Calculated and Reported Z Differ by ............ 0.50 Ratio
Alert level G
REFLT03_ALERT_1_G ALERT: Expected hkl max differ from CIF values
From the CIF: _diffrn_reflns_theta_max 27.99
From the CIF: _reflns_number_total 1066
From the CIF: _diffrn_reflns_limit_ max hkl 30. 46. 4.
From the CIF: _diffrn_reflns_limit_ min hkl -30. -46. -4.
TEST1: Expected hkl limits for theta max
Calculated maximum hkl 30. 48. 4.
Calculated minimum hkl -30. -48. -4.
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
correct. If it is not, please give the correct count in the
_publ_section_exptl_refinement section of the submitted CIF.
From the CIF: _diffrn_reflns_theta_max 27.99
From the CIF: _reflns_number_total 1066
Count of symmetry unique reflns 1082
Completeness (_total/calc) 98.52%
TEST3: Check Friedels for noncentro structure
Estimate of Friedel pairs measured 0
Fraction of Friedel pairs measured 0.000
Are heavy atom types Z>Si present no
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
3 ALERT level C = Check and explain
2 ALERT level G = General alerts; check
4 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
0 ALERT type 5 Informative message, check
Data collection: DENZO (Otwinowski & Minor, 1997); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97; molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.
7,8-dihydroxy-2
H-chromen-2-one hemihydrate
top
Crystal data top
C9H6O4·0.5H2O | F(000) = 1552 |
Mr = 187.15 | Dx = 1.592 Mg m−3 |
Orthorhombic, Fdd2 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: F 2 -2d | Cell parameters from 1066 reflections |
a = 22.990 (3) Å | θ = 2.8–28.0° |
b = 36.609 (5) Å | µ = 0.13 mm−1 |
c = 3.711 (3) Å | T = 298 K |
V = 3123 (3) Å3 | Prism, pale yellow |
Z = 16 | 0.50 × 0.25 × 0.20 mm |
Data collection top
MAC DIP 2030K diffractometer | 1048 reflections with I > 2σ(I) |
Radiation source: rotating anode | Rint = 0.045 |
Graphite monochromator | θmax = 28.0°, θmin = 2.8° |
Detector resolution: 0 pixels mm-1 | h = −30→30 |
ω scans | k = −46→46 |
3924 measured reflections | l = −4→4 |
1066 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)] = 0.043 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.110 | w = 1/[σ2(Fo2) + (0.0719P)2 + 2.386P] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max < 0.001 |
1066 reflections | Δρmax = 0.20 e Å−3 |
133 parameters | Δρmin = −0.22 e Å−3 |
1 restraint | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.049 (3) |
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 | |
O5 | 0.0000 | 0.0000 | 0.7104 (8) | 0.0431 (6) | |
H5O | −0.0212 (13) | 0.0088 (9) | 0.825 (13) | 0.065* | |
O1 | 0.10359 (6) | 0.11936 (3) | 0.2266 (5) | 0.0368 (4) | |
O2 | 0.10086 (7) | 0.17879 (4) | 0.2818 (7) | 0.0549 (6) | |
O3 | 0.09718 (6) | −0.00845 (4) | 0.1731 (6) | 0.0442 (5) | |
H3O | 0.1200 (13) | −0.0270 (9) | 0.106 (13) | 0.066* | |
O4 | 0.04674 (6) | 0.05747 (4) | 0.3330 (6) | 0.0409 (5) | |
H4O | 0.0388 (12) | 0.0383 (9) | 0.421 (12) | 0.061* | |
C2 | 0.12970 (8) | 0.15254 (5) | 0.1830 (7) | 0.0391 (5) | |
C3 | 0.18754 (9) | 0.15346 (6) | 0.0326 (8) | 0.0451 (6) | |
H3 | 0.2057 | 0.1758 | −0.0047 | 0.054* | |
C4 | 0.21558 (8) | 0.12261 (6) | −0.0541 (7) | 0.0418 (5) | |
H4 | 0.2530 | 0.1239 | −0.1485 | 0.050* | |
C4A | 0.18852 (8) | 0.08766 (5) | −0.0031 (6) | 0.0333 (5) | |
C5 | 0.21528 (8) | 0.05426 (6) | −0.0825 (7) | 0.0386 (5) | |
H5 | 0.2531 | 0.0538 | −0.1718 | 0.046* | |
C6 | 0.18550 (8) | 0.02200 (5) | −0.0279 (7) | 0.0382 (5) | |
H6 | 0.2029 | −0.0002 | −0.0854 | 0.046* | |
C7 | 0.12921 (8) | 0.02264 (5) | 0.1135 (6) | 0.0332 (5) | |
C8 | 0.10157 (8) | 0.05534 (5) | 0.2000 (7) | 0.0322 (5) | |
C8A | 0.13243 (8) | 0.08720 (4) | 0.1380 (6) | 0.0315 (5) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O5 | 0.0362 (10) | 0.0337 (10) | 0.0593 (15) | −0.0015 (7) | 0.000 | 0.000 |
O1 | 0.0346 (6) | 0.0233 (6) | 0.0525 (10) | −0.0005 (4) | 0.0088 (7) | −0.0031 (6) |
O2 | 0.0510 (8) | 0.0274 (7) | 0.0864 (16) | −0.0045 (5) | 0.0161 (10) | −0.0089 (9) |
O3 | 0.0433 (7) | 0.0249 (6) | 0.0643 (12) | 0.0038 (5) | 0.0048 (8) | −0.0026 (7) |
O4 | 0.0329 (7) | 0.0254 (6) | 0.0644 (11) | 0.0003 (4) | 0.0112 (8) | 0.0023 (7) |
C2 | 0.0397 (9) | 0.0235 (8) | 0.0540 (14) | −0.0068 (6) | 0.0043 (10) | −0.0027 (9) |
C3 | 0.0380 (9) | 0.0372 (9) | 0.0602 (15) | −0.0121 (7) | 0.0123 (11) | 0.0002 (10) |
C4 | 0.0317 (8) | 0.0457 (10) | 0.0480 (13) | −0.0053 (7) | 0.0062 (9) | −0.0018 (10) |
C4A | 0.0261 (7) | 0.0390 (9) | 0.0347 (11) | −0.0013 (6) | 0.0024 (8) | −0.0031 (8) |
C5 | 0.0288 (8) | 0.0446 (10) | 0.0423 (12) | 0.0069 (7) | 0.0043 (9) | −0.0020 (10) |
C6 | 0.0332 (8) | 0.0361 (9) | 0.0454 (13) | 0.0111 (7) | −0.0002 (9) | −0.0050 (10) |
C7 | 0.0329 (8) | 0.0273 (8) | 0.0394 (11) | 0.0019 (6) | −0.0009 (9) | −0.0007 (8) |
C8 | 0.0318 (8) | 0.0263 (8) | 0.0385 (11) | 0.0015 (6) | −0.0001 (8) | −0.0011 (8) |
C8A | 0.0289 (8) | 0.0273 (8) | 0.0382 (11) | 0.0024 (6) | 0.0011 (8) | −0.0040 (8) |
Geometric parameters (Å, º) top
O5—H5O | 0.72 (4) | C4—C4A | 1.435 (3) |
O1—C2 | 1.364 (2) | C4—H4 | 0.9300 |
O1—C8A | 1.3908 (19) | C4A—C8A | 1.392 (3) |
O2—C2 | 1.224 (3) | C4A—C5 | 1.400 (3) |
O3—C7 | 1.373 (2) | C5—C6 | 1.380 (3) |
O3—H3O | 0.89 (3) | C5—H5 | 0.9300 |
O4—C8 | 1.356 (2) | C6—C7 | 1.397 (3) |
O4—H4O | 0.80 (4) | C6—H6 | 0.9300 |
C2—C3 | 1.443 (3) | C7—C8 | 1.393 (2) |
C3—C4 | 1.340 (3) | C8—C8A | 1.384 (2) |
C3—H3 | 0.9300 | | |
| | | |
C2—O1—C8A | 121.06 (15) | C6—C5—C4A | 119.91 (18) |
C7—O3—H3O | 106 (2) | C6—C5—H5 | 120.0 |
C8—O4—H4O | 108 (2) | C4A—C5—H5 | 120.0 |
O2—C2—O1 | 115.17 (18) | C5—C6—C7 | 120.02 (17) |
O2—C2—C3 | 126.65 (17) | C5—C6—H6 | 120.0 |
O1—C2—C3 | 118.18 (17) | C7—C6—H6 | 120.0 |
C4—C3—C2 | 121.11 (18) | O3—C7—C8 | 115.51 (16) |
C4—C3—H3 | 119.4 | O3—C7—C6 | 122.91 (16) |
C2—C3—H3 | 119.4 | C8—C7—C6 | 121.58 (17) |
C3—C4—C4A | 120.76 (18) | O4—C8—C8A | 119.24 (15) |
C3—C4—H4 | 119.6 | O4—C8—C7 | 123.87 (16) |
C4A—C4—H4 | 119.6 | C8A—C8—C7 | 116.88 (17) |
C8A—C4A—C5 | 118.40 (17) | C8—C8A—O1 | 115.45 (15) |
C8A—C4A—C4 | 117.52 (16) | C8—C8A—C4A | 123.20 (16) |
C5—C4A—C4 | 124.08 (18) | O1—C8A—C4A | 121.35 (15) |
| | | |
C8A—O1—C2—O2 | −177.6 (2) | C6—C7—C8—O4 | 179.0 (2) |
C8A—O1—C2—C3 | 1.7 (4) | O3—C7—C8—C8A | −179.1 (2) |
O2—C2—C3—C4 | 177.6 (3) | C6—C7—C8—C8A | 0.2 (3) |
O1—C2—C3—C4 | −1.6 (4) | O4—C8—C8A—O1 | 1.0 (3) |
C2—C3—C4—C4A | 0.6 (4) | C7—C8—C8A—O1 | 179.9 (2) |
C3—C4—C4A—C8A | 0.2 (4) | O4—C8—C8A—C4A | −179.0 (2) |
C3—C4—C4A—C5 | −179.1 (2) | C7—C8—C8A—C4A | −0.1 (3) |
C8A—C4A—C5—C6 | 1.5 (3) | C2—O1—C8A—C8 | 179.0 (2) |
C4—C4A—C5—C6 | −179.3 (2) | C2—O1—C8A—C4A | −1.0 (3) |
C4A—C5—C6—C7 | −1.4 (4) | C5—C4A—C8A—C8 | −0.7 (3) |
C5—C6—C7—O3 | 179.8 (2) | C4—C4A—C8A—C8 | 180.0 (2) |
C5—C6—C7—C8 | 0.5 (4) | C5—C4A—C8A—O1 | 179.3 (2) |
O3—C7—C8—O4 | −0.3 (4) | C4—C4A—C8A—O1 | 0.0 (3) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O5—H5O···O3i | 0.72 (4) | 2.17 (4) | 2.835 (2) | 153 (4) |
O3—H3O···O2ii | 0.89 (3) | 1.77 (3) | 2.642 (2) | 163 (3) |
O4—H4O···O5 | 0.80 (4) | 1.98 (4) | 2.746 (2) | 162 (3) |
Symmetry codes: (i) −x, −y, z+1; (ii) −x+1/4, y−1/4, z−1/4. |