This single-crystal neutron diffraction study of (±)-camphoric anhydride [systematic name: (
RS)-1,8,8-trimethyl-3-oxabicyclo[3.2.1]octane-2,4-dione], C
10H
14O
3, at 110 K was undertaken to determine accurately the positions of the H atoms. The crystal packing of these molecules depends on intermolecular hydrogen bonding. The (+) and (−) molecules are held together by weak C—H
O interactions to form chains in the crystal structure.
Supporting information
CCDC reference: 270318
Key indicators
- Single-crystal neutron study
- T = 110 K
- Mean (C-C) = 0.003 Å
- R factor = 0.059
- wR factor = 0.057
- Data-to-parameter ratio = 6.5
checkCIF/PLATON results
No syntax errors found
Alert level B
REFNR01_ALERT_3_B Ratio of reflections to parameters is < 8 for a
centrosymmetric structure
sine(theta)/lambda 0.7637
Proportion of unique data used 0.4486
Ratio reflections to parameters 6.5061
PLAT088_ALERT_3_B Poor Data / Parameter Ratio .................... 6.51
Alert level C
ABSTM02_ALERT_3_C The ratio of Tmax/Tmin expected RT(exp) is > 1.10
Absorption corrections should be applied.
Tmin and Tmax expected: 0.640 0.757
RT(exp) = 1.182
PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low .... 45 Perc.
PLAT351_ALERT_3_C Long C-H Bond (0.96A) C4 - H4 ... 1.11 Ang.
PLAT351_ALERT_3_C Long C-H Bond (0.96A) C5 - H51 ... 1.11 Ang.
PLAT351_ALERT_3_C Long C-H Bond (0.96A) C8 - H83 ... 1.11 Ang.
PLAT351_ALERT_3_C Long C-H Bond (0.96A) C9 - H91 ... 1.12 Ang.
PLAT351_ALERT_3_C Long C-H Bond (0.96A) C10 - H101 ... 1.11 Ang.
0 ALERT level A = In general: serious problem
2 ALERT level B = Potentially serious problem
7 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
9 ALERT type 3 Indicator that the structure quality may be low
0 ALERT type 4 Improvement, methodology, query or suggestion
Data collection: DIF4N (modified Linux version of DIF4; Stoe & Cie, 1991); cell refinement: DIF4N; data reduction: PRON98 (modified version of REDU4; Stoe & Cie, 1990; Meven, Year?); program(s) used to solve structure: a previous X-ray study gave position parameters for heavy atoms (Reference?); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and CAMERON (Watkin et al., 1996); software used to prepare material for publication: CRYSTALS.
(±)-1,8,8-Trimethyl-3-oxabicyclo[3.2.1]octane-2,4-dione
top
Crystal data top
C10H14O3 | F(000) = 128 |
Mr = 182.22 | Dx = 1.268 Mg m−3 |
Monoclinic, P21/n | Neutron radiation, λ = 0.83300 Å |
Hall symbol: -P 2yn | Cell parameters from 15 reflections |
a = 6.5001 (8) Å | θ = 16–22° |
b = 11.5624 (14) Å | µ = 0.09 mm−1 |
c = 12.7093 (15) Å | T = 110 K |
β = 92.179 (2)° | Prism, colourless |
V = 954.5 (2) Å3 | 5.00 × 4.00 × 3.00 mm |
Z = 4 | |
Data collection top
5C2 four-circle (Orphée reactor, Saclay, France) diffractometer | θmax = 39.5°, θmin = 2.8° |
Cu_(220) monochromator | h = −9→9 |
ω scans | k = −17→1 |
4137 measured reflections | l = 0→19 |
3553 independent reflections | 2 standard reflections every 0 reflections |
1594 reflections with I > 3σ(I) | intensity decay: 0.0% |
Rint = 0.047 | |
Refinement top
Refinement on F | Hydrogen site location: difference Fourier map |
Least-squares matrix: full | All H-atom parameters refined |
R[F2 > 2σ(F2)] = 0.059 | Chebychev polynomial, (Watkin, 1994; Prince, 1982) W =
[weight][1-(ΔF/6σF)2]2 where [weight] = 1.0/[A0T0(x) + A1T1(x)
··· + An-1Tn-1(x)] where x = F /Fmax and Ai are the Chebychev
coefficients listed below: 0.703 -0.458 0.556 -0.177 0.795E-01 |
wR(F2) = 0.057 | (Δ/σ)max = 0.000154 |
S = 1.10 | Δρmax = 0.12 e Å−3 |
1594 reflections | Δρmin = −0.14 e Å−3 |
245 parameters | Extinction correction: Larson (1970), eq. 22 |
0 restraints | Extinction coefficient: 3.4 (8) |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
C1 | 0.7903 (3) | 0.71470 (18) | 0.48982 (16) | 0.0188 | |
C2 | 1.0199 (3) | 0.73790 (19) | 0.51432 (16) | 0.0203 | |
C3 | 1.0182 (3) | 0.87660 (18) | 0.36654 (17) | 0.0205 | |
C4 | 0.7950 (3) | 0.84498 (17) | 0.34358 (17) | 0.0194 | |
C5 | 0.6641 (3) | 0.9091 (2) | 0.42731 (19) | 0.0246 | |
C6 | 0.6682 (3) | 0.8264 (2) | 0.52484 (17) | 0.0223 | |
C7 | 0.7580 (3) | 0.71385 (19) | 0.36671 (16) | 0.0179 | |
C8 | 0.9082 (4) | 0.6336 (2) | 0.30866 (18) | 0.0245 | |
C9 | 0.5330 (3) | 0.6807 (2) | 0.33370 (19) | 0.0252 | |
C10 | 0.7222 (4) | 0.6053 (2) | 0.54726 (19) | 0.0270 | |
O1 | 1.1120 (4) | 0.8274 (2) | 0.4582 (2) | 0.0230 | |
O2 | 1.1304 (4) | 0.6881 (3) | 0.5787 (2) | 0.0298 | |
O3 | 1.1226 (4) | 0.9430 (3) | 0.3174 (2) | 0.0299 | |
H4 | 0.7553 (9) | 0.8694 (5) | 0.2608 (4) | 0.0375 | |
H51 | 0.5050 (8) | 0.9217 (6) | 0.3956 (5) | 0.0447 | |
H52 | 0.7279 (9) | 0.9952 (5) | 0.4473 (5) | 0.0415 | |
H61 | 0.5119 (8) | 0.8000 (5) | 0.5448 (5) | 0.0410 | |
H62 | 0.7425 (9) | 0.8663 (5) | 0.5953 (4) | 0.0400 | |
H81 | 1.0727 (9) | 0.6545 (6) | 0.3224 (5) | 0.0444 | |
H82 | 0.8782 (11) | 0.6388 (7) | 0.2230 (5) | 0.0512 | |
H83 | 0.8850 (11) | 0.5424 (5) | 0.3326 (6) | 0.0500 | |
H90 | 0.4183 (8) | 0.7281 (6) | 0.3787 (6) | 0.0519 | |
H91 | 0.5080 (10) | 0.5859 (5) | 0.3443 (6) | 0.0489 | |
H92 | 0.5043 (10) | 0.7008 (7) | 0.2502 (5) | 0.0531 | |
H101 | 0.7994 (11) | 0.5271 (6) | 0.5177 (6) | 0.0517 | |
H102 | 0.5553 (9) | 0.5949 (6) | 0.5393 (5) | 0.0456 | |
H103 | 0.7621 (11) | 0.6094 (7) | 0.6320 (5) | 0.0508 | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C1 | 0.0169 (8) | 0.0212 (8) | 0.0183 (8) | −0.0020 (7) | 0.0018 (6) | 0.0007 (7) |
C2 | 0.0165 (8) | 0.0247 (10) | 0.0197 (8) | −0.0001 (7) | −0.0002 (6) | 0.0019 (7) |
C3 | 0.0184 (8) | 0.0212 (9) | 0.0219 (8) | −0.0022 (7) | 0.0018 (7) | 0.0004 (7) |
C4 | 0.0176 (8) | 0.0196 (9) | 0.0209 (8) | −0.0018 (7) | −0.0019 (6) | 0.0016 (7) |
C5 | 0.0221 (9) | 0.0206 (9) | 0.0309 (10) | 0.0028 (7) | −0.0001 (8) | −0.0031 (8) |
C6 | 0.0181 (8) | 0.0264 (9) | 0.0225 (9) | 0.0006 (7) | 0.0025 (7) | −0.0047 (8) |
C7 | 0.0155 (8) | 0.0192 (8) | 0.0189 (8) | −0.0010 (6) | 0.0005 (6) | −0.0028 (7) |
C8 | 0.0255 (10) | 0.0243 (9) | 0.0239 (9) | 0.0009 (8) | 0.0043 (8) | −0.0053 (8) |
C9 | 0.0199 (9) | 0.0281 (10) | 0.0275 (10) | −0.0074 (8) | −0.0013 (7) | −0.0025 (9) |
C10 | 0.0273 (10) | 0.0282 (10) | 0.0256 (10) | −0.0059 (8) | 0.0020 (8) | 0.0052 (8) |
O1 | 0.0177 (9) | 0.0272 (11) | 0.0239 (10) | −0.0026 (9) | −0.0006 (8) | −0.0013 (9) |
O2 | 0.0250 (12) | 0.0377 (15) | 0.0260 (11) | 0.0022 (10) | −0.0065 (9) | 0.0061 (11) |
O3 | 0.0280 (13) | 0.0309 (13) | 0.0313 (13) | −0.0088 (10) | 0.0058 (10) | 0.0073 (10) |
H4 | 0.039 (2) | 0.042 (3) | 0.030 (2) | −0.005 (2) | −0.0050 (18) | 0.009 (2) |
H51 | 0.025 (2) | 0.050 (3) | 0.058 (3) | 0.004 (2) | −0.002 (2) | 0.000 (3) |
H52 | 0.043 (3) | 0.029 (2) | 0.053 (3) | −0.0010 (19) | −0.002 (2) | −0.010 (2) |
H61 | 0.031 (2) | 0.048 (3) | 0.045 (3) | 0.001 (2) | 0.0121 (19) | −0.004 (2) |
H62 | 0.043 (3) | 0.044 (3) | 0.032 (2) | 0.004 (2) | −0.003 (2) | −0.015 (2) |
H81 | 0.032 (2) | 0.047 (3) | 0.055 (3) | 0.003 (2) | 0.006 (2) | −0.008 (2) |
H82 | 0.054 (3) | 0.069 (4) | 0.031 (2) | 0.002 (3) | 0.006 (2) | −0.013 (3) |
H83 | 0.053 (3) | 0.027 (2) | 0.071 (4) | 0.000 (2) | 0.013 (3) | −0.001 (2) |
H90 | 0.024 (2) | 0.061 (4) | 0.070 (4) | −0.001 (2) | 0.000 (2) | −0.018 (3) |
H91 | 0.041 (3) | 0.037 (3) | 0.068 (4) | −0.012 (2) | −0.007 (3) | −0.002 (3) |
H92 | 0.041 (3) | 0.080 (5) | 0.037 (3) | −0.009 (3) | −0.010 (2) | 0.004 (3) |
H101 | 0.061 (4) | 0.041 (3) | 0.054 (4) | 0.004 (3) | 0.014 (3) | 0.008 (3) |
H102 | 0.033 (2) | 0.051 (3) | 0.053 (3) | −0.010 (2) | 0.007 (2) | 0.012 (3) |
H103 | 0.062 (4) | 0.058 (4) | 0.032 (2) | −0.008 (3) | 0.001 (2) | 0.011 (3) |
Geometric parameters (Å, º) top
C1—C2 | 1.536 (3) | C5—H52 | 1.104 (6) |
C1—C6 | 1.589 (3) | C6—H61 | 1.100 (6) |
C1—C7 | 1.571 (3) | C6—H62 | 1.103 (5) |
C1—C10 | 1.534 (3) | C7—C8 | 1.553 (3) |
C2—O1 | 1.403 (3) | C7—C9 | 1.555 (3) |
C2—O2 | 1.214 (3) | C8—H81 | 1.104 (6) |
C3—C4 | 1.513 (3) | C8—H82 | 1.101 (6) |
C3—O1 | 1.414 (3) | C8—H83 | 1.109 (6) |
C3—O3 | 1.214 (3) | C9—H90 | 1.103 (7) |
C4—C5 | 1.573 (3) | C9—H91 | 1.117 (7) |
C4—C7 | 1.565 (3) | C9—H92 | 1.095 (6) |
C4—H4 | 1.111 (5) | C10—H101 | 1.107 (7) |
C5—C6 | 1.565 (3) | C10—H102 | 1.093 (6) |
C5—H51 | 1.105 (6) | C10—H103 | 1.099 (6) |
| | | |
C2—C1—C6 | 107.05 (17) | C1—C6—H62 | 111.0 (3) |
C2—C1—C7 | 107.15 (16) | H61—C6—H62 | 108.0 (5) |
C6—C1—C7 | 103.58 (16) | C4—C7—C1 | 99.52 (15) |
C2—C1—C10 | 110.06 (17) | C4—C7—C8 | 112.71 (16) |
C6—C1—C10 | 112.38 (18) | C1—C7—C8 | 114.47 (18) |
C7—C1—C10 | 116.04 (18) | C4—C7—C9 | 109.76 (17) |
C1—C2—O1 | 117.09 (19) | C1—C7—C9 | 111.04 (17) |
C1—C2—O2 | 126.8 (2) | C8—C7—C9 | 109.04 (18) |
O1—C2—O2 | 116.1 (2) | C7—C8—H81 | 114.6 (4) |
C4—C3—O1 | 116.22 (19) | C7—C8—H82 | 110.2 (4) |
C4—C3—O3 | 127.2 (2) | H81—C8—H82 | 106.1 (6) |
O1—C3—O3 | 116.5 (2) | C7—C8—H83 | 110.1 (4) |
C3—C4—C5 | 107.14 (17) | H81—C8—H83 | 107.8 (5) |
C3—C4—C7 | 110.55 (16) | H82—C8—H83 | 107.7 (6) |
C5—C4—C7 | 103.82 (16) | C7—C9—H90 | 112.6 (4) |
C3—C4—H4 | 107.9 (3) | C7—C9—H91 | 110.4 (4) |
C5—C4—H4 | 114.1 (4) | H90—C9—H91 | 108.7 (6) |
C7—C4—H4 | 113.1 (3) | C7—C9—H92 | 109.4 (4) |
C4—C5—C6 | 104.74 (17) | H90—C9—H92 | 107.7 (6) |
C4—C5—H51 | 109.8 (4) | H91—C9—H92 | 107.7 (6) |
C6—C5—H51 | 110.9 (4) | C1—C10—H101 | 111.7 (4) |
C4—C5—H52 | 111.9 (4) | C1—C10—H102 | 110.5 (4) |
C6—C5—H52 | 111.9 (4) | H101—C10—H102 | 109.8 (6) |
H51—C5—H52 | 107.7 (5) | C1—C10—H103 | 111.7 (4) |
C5—C6—C1 | 105.57 (16) | H101—C10—H103 | 106.0 (6) |
C5—C6—H61 | 111.4 (4) | H102—C10—H103 | 107.0 (6) |
C1—C6—H61 | 108.3 (4) | C3—O1—C2 | 122.5 (2) |
C5—C6—H62 | 112.5 (4) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C4—H4···O2i | 1.110 (6) | 2.513 (6) | 3.514 (3) | 149.4 (4) |
C5—H52···O1ii | 1.104 (6) | 2.576 (6) | 3.655 (3) | 165.1 (5) |
C9—H90···O1iii | 1.103 (7) | 2.541 (7) | 3.633 (3) | 170.5 (5) |
Symmetry codes: (i) x−1/2, −y+3/2, z−1/2; (ii) −x+2, −y+2, −z+1; (iii) x−1, y, z. |