Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807042924/nc2049sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807042924/nc2049Isup2.hkl |
CCDC reference: 663706
Key indicators
- Single-crystal X-ray study
- T = 200 K
- Mean (C-C) = 0.003 Å
- R factor = 0.031
- wR factor = 0.081
- Data-to-parameter ratio = 9.9
checkCIF/PLATON results
No syntax errors found
Alert level B PLAT432_ALERT_2_B Short Inter X...Y Contact O2 .. C1 .. 2.91 Ang.
Author Response: Carbonyl-carbonyl interaction features short O...C contact. (see Allen et al. (1998) B54, 320-329) |
Alert level C PLAT369_ALERT_2_C Long C(sp2)-C(sp2) Bond C1 - C2 ... 1.56 Ang.
Author Response: C-C bond in -C(=O)-C(=O)- system under consideration |
PLAT432_ALERT_2_C Short Inter X...Y Contact O1 .. C2 .. 2.99 Ang.
Author Response: Carbonyl-carbonyl interaction features short O...C contact. (see Allen et al. (1998) B54, 320-329) |
PLAT432_ALERT_2_C Short Inter X...Y Contact O1 .. C1 .. 3.00 Ang.
Author Response: Carbonyl-carbonyl interaction features short O...C contact. (see Allen et al. (1998) B54, 320-329) |
Alert level G 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 27.48 From the CIF: _reflns_number_total 557 Count of symmetry unique reflns 559 Completeness (_total/calc) 99.64% 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 1 ALERT level B = Potentially serious problem 3 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 4 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
The title compound was prepared according to a published procedure (Heine, 1971) by reaction of bromine on 1,2-bis(trimethylsilyloxy)-cyclobut-1,2-ene in n-pentane. Crystals were obtained upon warming to room temperature and storage of the reaction batch at ambient temperature under exclusion of light for 72 h.
Spectroscopic data: 1H NMR (399.8 MHz, CDCl3, 24 °C) δ/p.p.m.: 3.07 (s, 4 H, CH2). 13C{1H} NMR (100.5 MHz, CDCl3, 26 °C) δ/p.p.m.: 207.3 (CO), 41.8 (CH2).
All H atoms were located in a difference map and refined as riding on their parent atoms. One common isotropic displacement parameter for all H atoms was refined to Uiso(H) = 0.048 (3) Å2.
Due to the absence of significant anomalous scattering the absolute structure factor (Flack, 1983), which is 2.9 with an estimated standard deviation of 2 for the unmerged data set, is meaningless. Thus, Friedel opposites (351 pairs) have been merged. The absolute structure has been arbitrarily chosen.
The title compound, C4H4O2, was prepared as an intermediate in the synthesis of α-hydroxycyclopropanecarboxylic acid. In the crystal structure the cyclobutane ring is almost planar (Fig. 1).
Details of the synthesis of the title compound were given by Heine (1971). For related literature, see: Flack (1983).
Data collection: Collect (Bruker–Nonius, 2004); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL 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: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).
Fig. 1. The molecular structure of (I), with atom labels and anisotropic displacement ellipsoids (drawn at 50% probability level) for non-H atoms. |
C4H4O2 | F(000) = 176 |
Mr = 84.07 | Dx = 1.394 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 5161 reflections |
a = 5.3719 (3) Å | θ = 3.1–27.5° |
b = 6.8819 (3) Å | µ = 0.11 mm−1 |
c = 10.8378 (6) Å | T = 200 K |
V = 400.66 (4) Å3 | Block, yellow–orange |
Z = 4 | 0.20 × 0.17 × 0.14 mm |
Nonius KappaCCD diffractometer | 488 reflections with I > 2σ(I) |
Radiation source: rotating anode | Rint = 0.038 |
MONTEL, graded multilayered X-ray optics monochromator | θmax = 27.5°, θmin = 3.5° |
CCD; rotation images; thick slices scans | h = −6→6 |
3074 measured reflections | k = −8→8 |
557 independent reflections | l = −13→14 |
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)] = 0.031 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.081 | Only H-atom displacement parameters refined |
S = 1.09 | w = 1/[σ2(Fo2) + (0.0567P)2 + 0.294P] where P = (Fo2 + 2Fc2)/3 |
557 reflections | (Δ/σ)max < 0.001 |
56 parameters | Δρmax = 0.12 e Å−3 |
0 restraints | Δρmin = −0.15 e Å−3 |
C4H4O2 | V = 400.66 (4) Å3 |
Mr = 84.07 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 5.3719 (3) Å | µ = 0.11 mm−1 |
b = 6.8819 (3) Å | T = 200 K |
c = 10.8378 (6) Å | 0.20 × 0.17 × 0.14 mm |
Nonius KappaCCD diffractometer | 488 reflections with I > 2σ(I) |
3074 measured reflections | Rint = 0.038 |
557 independent reflections |
R[F2 > 2σ(F2)] = 0.031 | 0 restraints |
wR(F2) = 0.081 | Only H-atom displacement parameters refined |
S = 1.09 | Δρmax = 0.12 e Å−3 |
557 reflections | Δρmin = −0.15 e Å−3 |
56 parameters |
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 | ||
O1 | 0.0632 (3) | 0.2198 (2) | 0.25237 (14) | 0.0496 (4) | |
O2 | −0.0783 (3) | 0.42078 (19) | 0.51173 (12) | 0.0429 (4) | |
C1 | 0.1626 (4) | 0.3358 (2) | 0.31712 (16) | 0.0327 (4) | |
C2 | 0.0924 (3) | 0.4362 (2) | 0.44147 (14) | 0.0310 (4) | |
C3 | 0.3323 (4) | 0.5531 (3) | 0.43585 (16) | 0.0359 (4) | |
H31 | 0.4477 | 0.5256 | 0.5049 | 0.048 (3)* | |
H32 | 0.3051 | 0.6947 | 0.4267 | 0.048 (3)* | |
C4 | 0.4048 (4) | 0.4512 (3) | 0.31457 (16) | 0.0358 (4) | |
H41 | 0.4181 | 0.5408 | 0.2434 | 0.048 (3)* | |
H42 | 0.5555 | 0.3693 | 0.3216 | 0.048 (3)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0511 (9) | 0.0464 (8) | 0.0513 (7) | −0.0045 (8) | −0.0136 (9) | −0.0149 (7) |
O2 | 0.0370 (7) | 0.0500 (8) | 0.0416 (7) | 0.0022 (7) | 0.0056 (7) | 0.0056 (6) |
C1 | 0.0340 (9) | 0.0310 (8) | 0.0331 (8) | 0.0007 (8) | −0.0038 (8) | 0.0012 (7) |
C2 | 0.0303 (9) | 0.0314 (8) | 0.0311 (8) | 0.0020 (8) | −0.0043 (8) | 0.0029 (7) |
C3 | 0.0328 (9) | 0.0337 (9) | 0.0413 (9) | −0.0030 (8) | −0.0033 (8) | −0.0053 (8) |
C4 | 0.0338 (9) | 0.0356 (9) | 0.0380 (8) | −0.0026 (8) | 0.0028 (8) | 0.0031 (8) |
O1—C1 | 1.190 (2) | C3—C4 | 1.540 (2) |
O2—C2 | 1.196 (2) | C3—H31 | 0.9900 |
C1—C4 | 1.524 (3) | C3—H32 | 0.9900 |
C1—C2 | 1.561 (2) | C4—H41 | 0.9900 |
C2—C3 | 1.520 (3) | C4—H42 | 0.9900 |
O1—C1—C4 | 136.23 (18) | C2—C3—H32 | 113.6 |
O1—C1—C2 | 134.26 (18) | C4—C3—H32 | 113.6 |
C4—C1—C2 | 89.50 (13) | H31—C3—H32 | 110.8 |
O2—C2—C3 | 136.21 (16) | C1—C4—C3 | 90.33 (14) |
O2—C2—C1 | 134.07 (17) | C1—C4—H41 | 113.6 |
C3—C2—C1 | 89.70 (13) | C3—C4—H41 | 113.6 |
C2—C3—C4 | 90.44 (13) | C1—C4—H42 | 113.6 |
C2—C3—H31 | 113.6 | C3—C4—H42 | 113.6 |
C4—C3—H31 | 113.6 | H41—C4—H42 | 110.9 |
O1—C1—C2—O2 | 3.7 (4) | C1—C2—C3—C4 | −1.11 (12) |
C4—C1—C2—O2 | −177.2 (2) | O1—C1—C4—C3 | 178.0 (2) |
O1—C1—C2—C3 | −178.0 (2) | C2—C1—C4—C3 | −1.11 (12) |
C4—C1—C2—C3 | 1.12 (12) | C2—C3—C4—C1 | 1.14 (13) |
O2—C2—C3—C4 | 177.2 (2) |
Experimental details
Crystal data | |
Chemical formula | C4H4O2 |
Mr | 84.07 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 200 |
a, b, c (Å) | 5.3719 (3), 6.8819 (3), 10.8378 (6) |
V (Å3) | 400.66 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.11 |
Crystal size (mm) | 0.20 × 0.17 × 0.14 |
Data collection | |
Diffractometer | Nonius KappaCCD |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3074, 557, 488 |
Rint | 0.038 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.031, 0.081, 1.09 |
No. of reflections | 557 |
No. of parameters | 56 |
H-atom treatment | Only H-atom displacement parameters refined |
Δρmax, Δρmin (e Å−3) | 0.12, −0.15 |
Computer programs: Collect (Bruker–Nonius, 2004), HKL SCALEPACK (Otwinowski & Minor, 1997), HKL DENZO and SCALEPACK (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEPIII (Burnett & Johnson, 1996).
The title compound, C4H4O2, was prepared as an intermediate in the synthesis of α-hydroxycyclopropanecarboxylic acid. In the crystal structure the cyclobutane ring is almost planar (Fig. 1).