organic compounds
2-(2-Methyl-1,3-dioxolan-2-yl)-1,1-diphenylethanol
aChemistry, Queensland University of Technology, 2 George St, Brisbane, Queensland 4001, Australia
*Correspondence e-mail: j.mcmurtrie@qut.edu.au
The molecules of the title compound, C18H20O3, display an intramolecular O—H⋯O hydrogen bond between the hydroxy donor and a ketal O-atom acceptor. In the crystal, intermolecular C—H⋯π interactions connect adjacent molecules into chains parallel to the b axis.
Experimental
Crystal data
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Refinement
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Data collection: CrysAlis CCD (Oxford Diffraction, 2007); cell CrysAlis RED (Oxford Diffraction, 2007); data reduction: CrysAlis RED; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: publCIF (Westrip, 2009).
Supporting information
10.1107/S1600536809053227/jh2121sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536809053227/jh2121Isup2.hkl
The title compound was prepared by the procedure reported by Paulson et al. (1973). Large crystalline plates were obtained from methanol/water by vapour diffusion. NMR 1H (300 MHz, CDCl3) 7.53 (m, 4H, ortho-H), 7.30 (m, 4H, meta-H), 7.18 (tt, 2H, para-H), 5.39 (s, 1H, OH), 3.9–3.6 (symmetrical multiplets, AA'BB', 4H, ketal ring H), 2.84 (s, 2H, CH2), 1.07 (s, 3H, CH3).
C-bound H atoms were included in idealized positions and refined using a riding model approximation with methylene, methyl and aromatic bond lengths fixed at 0.99, 0.98 and 0.95 Å, respectively. Uiso(H) values were fixed at 1.2Ueq of the parent C atoms for methylene and aromatic H atoms and 1.5Ueq of the parent C atoms for methyl H atoms. The hydroxy H atom was located in a Fourier difference map and refined with an O—H bond length restraint of 0.98 Å and with Uiso fixed at 1.5Ueq of the parent O atom.
Data collection: CrysAlis CCD (Oxford Diffraction, 2007); cell
CrysAlis RED (Oxford Diffraction, 2007); data reduction: CrysAlis RED (Oxford Diffraction, 2007); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: publCIF (Westrip, 2009).C18H20O3 | F(000) = 608 |
Mr = 284.34 | Dx = 1.241 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 5.7961 (4) Å | Cell parameters from 2617 reflections |
b = 8.8271 (7) Å | θ = 3.4–28.6° |
c = 29.754 (2) Å | µ = 0.08 mm−1 |
β = 92.150 (7)° | T = 173 K |
V = 1521.26 (19) Å3 | Plate, colourless |
Z = 4 | 0.68 × 0.35 × 0.09 mm |
Oxford Diffraction Gemini diffractometer | 3407 independent reflections |
Radiation source: Enhance (Mo) X-ray Source | 2458 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.017 |
Detector resolution: 16.0774 pixels mm-1 | θmax = 28.7°, θmin = 3.5° |
ω scans | h = −4→7 |
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2007) | k = −11→10 |
Tmin = 0.974, Tmax = 1.000 | l = −37→37 |
5871 measured reflections |
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)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.100 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0523P)2] where P = (Fo2 + 2Fc2)/3 |
3407 reflections | (Δ/σ)max = 0.001 |
194 parameters | Δρmax = 0.23 e Å−3 |
1 restraint | Δρmin = −0.19 e Å−3 |
C18H20O3 | V = 1521.26 (19) Å3 |
Mr = 284.34 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 5.7961 (4) Å | µ = 0.08 mm−1 |
b = 8.8271 (7) Å | T = 173 K |
c = 29.754 (2) Å | 0.68 × 0.35 × 0.09 mm |
β = 92.150 (7)° |
Oxford Diffraction Gemini diffractometer | 3407 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2007) | 2458 reflections with I > 2σ(I) |
Tmin = 0.974, Tmax = 1.000 | Rint = 0.017 |
5871 measured reflections |
R[F2 > 2σ(F2)] = 0.041 | 1 restraint |
wR(F2) = 0.100 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.23 e Å−3 |
3407 reflections | Δρmin = −0.19 e Å−3 |
194 parameters |
Experimental. CrysAlisPro, Oxford Diffraction Ltd., Version 1.171.33.52 (release 06-11-2009 CrysAlis171 .NET) (compiled Nov 6 2009,16:24:50) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. |
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 | ||
C1 | 0.9148 (2) | 0.35245 (18) | 0.06596 (5) | 0.0381 (4) | |
H1A | 0.9150 | 0.2620 | 0.0468 | 0.057* | |
H1B | 1.0740 | 0.3862 | 0.0720 | 0.057* | |
H1C | 0.8270 | 0.4333 | 0.0506 | 0.057* | |
C2 | 0.8042 (2) | 0.31506 (15) | 0.10991 (4) | 0.0276 (3) | |
C3 | 0.7536 (3) | 0.10241 (17) | 0.15222 (6) | 0.0450 (4) | |
H3A | 0.7242 | 0.1454 | 0.1822 | 0.054* | |
H3B | 0.8023 | −0.0046 | 0.1558 | 0.054* | |
C4 | 0.5432 (3) | 0.11605 (17) | 0.12092 (6) | 0.0465 (4) | |
H4A | 0.5403 | 0.0347 | 0.0980 | 0.056* | |
H4B | 0.3994 | 0.1112 | 0.1378 | 0.056* | |
C5 | 0.8041 (2) | 0.44391 (13) | 0.14479 (4) | 0.0214 (3) | |
H5A | 0.9611 | 0.4883 | 0.1463 | 0.026* | |
H5B | 0.7780 | 0.3976 | 0.1745 | 0.026* | |
C6 | 0.63093 (18) | 0.57549 (14) | 0.13839 (4) | 0.0193 (3) | |
C7 | 0.6771 (2) | 0.67148 (14) | 0.09647 (4) | 0.0213 (3) | |
C8 | 0.8846 (2) | 0.74953 (15) | 0.09357 (4) | 0.0300 (3) | |
H8 | 0.9982 | 0.7406 | 0.1173 | 0.036* | |
C9 | 0.9288 (2) | 0.83969 (17) | 0.05699 (5) | 0.0387 (4) | |
H9 | 1.0708 | 0.8931 | 0.0559 | 0.046* | |
C10 | 0.7661 (3) | 0.85235 (18) | 0.02188 (5) | 0.0402 (4) | |
H10 | 0.7960 | 0.9139 | −0.0034 | 0.048* | |
C11 | 0.5610 (3) | 0.77505 (18) | 0.02399 (5) | 0.0410 (4) | |
H11 | 0.4495 | 0.7829 | −0.0001 | 0.049* | |
C12 | 0.5150 (2) | 0.68539 (15) | 0.06104 (4) | 0.0306 (3) | |
H12 | 0.3719 | 0.6333 | 0.0622 | 0.037* | |
C13 | 0.6400 (2) | 0.68055 (13) | 0.17969 (4) | 0.0208 (3) | |
C14 | 0.4531 (2) | 0.77607 (15) | 0.18647 (5) | 0.0318 (3) | |
H14 | 0.3254 | 0.7752 | 0.1655 | 0.038* | |
C15 | 0.4502 (3) | 0.87249 (17) | 0.22329 (5) | 0.0413 (4) | |
H15 | 0.3211 | 0.9368 | 0.2273 | 0.050* | |
C16 | 0.6344 (3) | 0.87537 (17) | 0.25425 (5) | 0.0391 (4) | |
H16 | 0.6322 | 0.9406 | 0.2796 | 0.047* | |
C17 | 0.8203 (3) | 0.78268 (16) | 0.24777 (5) | 0.0388 (4) | |
H17 | 0.9478 | 0.7846 | 0.2688 | 0.047* | |
C18 | 0.8250 (2) | 0.68578 (15) | 0.21082 (4) | 0.0289 (3) | |
H18 | 0.9556 | 0.6228 | 0.2069 | 0.035* | |
O1 | 0.92307 (16) | 0.18920 (10) | 0.12962 (3) | 0.0369 (3) | |
O2 | 0.56966 (15) | 0.26253 (10) | 0.10043 (3) | 0.0344 (2) | |
O3 | 0.39885 (13) | 0.51655 (10) | 0.13579 (3) | 0.0244 (2) | |
H1O | 0.409 (2) | 0.4207 (11) | 0.1220 (4) | 0.037* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0378 (8) | 0.0446 (9) | 0.0321 (8) | 0.0005 (7) | 0.0053 (6) | −0.0139 (7) |
C2 | 0.0236 (6) | 0.0255 (7) | 0.0335 (7) | 0.0007 (6) | −0.0033 (5) | −0.0071 (6) |
C3 | 0.0514 (10) | 0.0226 (8) | 0.0614 (10) | −0.0015 (7) | 0.0062 (8) | −0.0012 (7) |
C4 | 0.0409 (9) | 0.0264 (8) | 0.0726 (12) | −0.0062 (7) | 0.0069 (8) | −0.0054 (8) |
C5 | 0.0208 (6) | 0.0232 (7) | 0.0199 (6) | −0.0019 (5) | −0.0009 (5) | −0.0005 (5) |
C6 | 0.0166 (6) | 0.0227 (6) | 0.0188 (6) | −0.0030 (5) | 0.0002 (5) | 0.0006 (5) |
C7 | 0.0229 (6) | 0.0222 (6) | 0.0190 (6) | 0.0022 (5) | 0.0023 (5) | −0.0001 (5) |
C8 | 0.0259 (7) | 0.0365 (8) | 0.0275 (7) | −0.0024 (6) | 0.0009 (5) | 0.0066 (6) |
C9 | 0.0338 (8) | 0.0415 (9) | 0.0414 (8) | −0.0036 (7) | 0.0099 (6) | 0.0131 (7) |
C10 | 0.0485 (9) | 0.0439 (9) | 0.0291 (7) | 0.0100 (7) | 0.0122 (7) | 0.0169 (7) |
C11 | 0.0451 (9) | 0.0525 (10) | 0.0248 (7) | 0.0059 (8) | −0.0052 (6) | 0.0090 (7) |
C12 | 0.0299 (7) | 0.0352 (8) | 0.0265 (7) | 0.0000 (6) | −0.0039 (5) | 0.0030 (6) |
C13 | 0.0235 (6) | 0.0196 (6) | 0.0194 (6) | −0.0038 (5) | 0.0036 (5) | 0.0014 (5) |
C14 | 0.0269 (7) | 0.0347 (8) | 0.0340 (7) | 0.0012 (6) | 0.0028 (6) | −0.0068 (6) |
C15 | 0.0371 (8) | 0.0392 (8) | 0.0487 (9) | 0.0027 (7) | 0.0148 (7) | −0.0157 (8) |
C16 | 0.0486 (9) | 0.0384 (8) | 0.0311 (8) | −0.0096 (7) | 0.0112 (7) | −0.0133 (7) |
C17 | 0.0465 (9) | 0.0411 (9) | 0.0281 (7) | −0.0070 (7) | −0.0071 (6) | −0.0071 (7) |
C18 | 0.0312 (7) | 0.0279 (7) | 0.0273 (7) | 0.0007 (6) | −0.0027 (5) | −0.0023 (6) |
O1 | 0.0331 (5) | 0.0252 (5) | 0.0521 (6) | 0.0051 (4) | −0.0017 (5) | −0.0042 (5) |
O2 | 0.0286 (5) | 0.0299 (5) | 0.0443 (6) | −0.0050 (4) | −0.0044 (4) | −0.0100 (5) |
O3 | 0.0187 (4) | 0.0257 (5) | 0.0288 (5) | −0.0043 (4) | 0.0015 (3) | −0.0015 (4) |
C1—C2 | 1.5145 (18) | C8—C9 | 1.3802 (18) |
C1—H1A | 0.9800 | C8—H8 | 0.9500 |
C1—H1B | 0.9800 | C9—C10 | 1.385 (2) |
C1—H1C | 0.9800 | C9—H9 | 0.9500 |
C2—O1 | 1.4222 (16) | C10—C11 | 1.374 (2) |
C2—O2 | 1.4539 (15) | C10—H10 | 0.9500 |
C2—C5 | 1.5396 (17) | C11—C12 | 1.3912 (19) |
C3—O1 | 1.4330 (17) | C11—H11 | 0.9500 |
C3—C4 | 1.511 (2) | C12—H12 | 0.9500 |
C3—H3A | 0.9900 | C13—C18 | 1.3914 (18) |
C3—H3B | 0.9900 | C13—C14 | 1.3932 (17) |
C4—O2 | 1.4402 (17) | C14—C15 | 1.3879 (19) |
C4—H4A | 0.9900 | C14—H14 | 0.9500 |
C4—H4B | 0.9900 | C15—C16 | 1.384 (2) |
C5—C6 | 1.5422 (17) | C15—H15 | 0.9500 |
C5—H5A | 0.9900 | C16—C17 | 1.372 (2) |
C5—H5B | 0.9900 | C16—H16 | 0.9500 |
C6—O3 | 1.4416 (13) | C17—C18 | 1.3940 (18) |
C6—C13 | 1.5387 (16) | C17—H17 | 0.9500 |
C6—C7 | 1.5398 (16) | C18—H18 | 0.9500 |
C7—C12 | 1.3908 (18) | O3—H1O | 0.943 (8) |
C7—C8 | 1.3914 (17) | ||
C2—C1—H1A | 109.5 | C8—C7—C6 | 119.97 (11) |
C2—C1—H1B | 109.5 | C9—C8—C7 | 121.39 (13) |
H1A—C1—H1B | 109.5 | C9—C8—H8 | 119.3 |
C2—C1—H1C | 109.5 | C7—C8—H8 | 119.3 |
H1A—C1—H1C | 109.5 | C8—C9—C10 | 119.99 (13) |
H1B—C1—H1C | 109.5 | C8—C9—H9 | 120.0 |
O1—C2—O2 | 105.42 (10) | C10—C9—H9 | 120.0 |
O1—C2—C1 | 108.18 (10) | C11—C10—C9 | 119.42 (13) |
O2—C2—C1 | 108.96 (11) | C11—C10—H10 | 120.3 |
O1—C2—C5 | 108.16 (10) | C9—C10—H10 | 120.3 |
O2—C2—C5 | 110.03 (10) | C10—C11—C12 | 120.71 (13) |
C1—C2—C5 | 115.59 (11) | C10—C11—H11 | 119.6 |
O1—C3—C4 | 102.69 (13) | C12—C11—H11 | 119.6 |
O1—C3—H3A | 111.2 | C7—C12—C11 | 120.43 (13) |
C4—C3—H3A | 111.2 | C7—C12—H12 | 119.8 |
O1—C3—H3B | 111.2 | C11—C12—H12 | 119.8 |
C4—C3—H3B | 111.2 | C18—C13—C14 | 117.86 (12) |
H3A—C3—H3B | 109.1 | C18—C13—C6 | 123.64 (11) |
O2—C4—C3 | 103.66 (11) | C14—C13—C6 | 118.50 (11) |
O2—C4—H4A | 111.0 | C15—C14—C13 | 121.21 (13) |
C3—C4—H4A | 111.0 | C15—C14—H14 | 119.4 |
O2—C4—H4B | 111.0 | C13—C14—H14 | 119.4 |
C3—C4—H4B | 111.0 | C16—C15—C14 | 120.30 (13) |
H4A—C4—H4B | 109.0 | C16—C15—H15 | 119.8 |
C2—C5—C6 | 119.34 (10) | C14—C15—H15 | 119.8 |
C2—C5—H5A | 107.5 | C17—C16—C15 | 119.07 (13) |
C6—C5—H5A | 107.5 | C17—C16—H16 | 120.5 |
C2—C5—H5B | 107.5 | C15—C16—H16 | 120.5 |
C6—C5—H5B | 107.5 | C16—C17—C18 | 121.00 (13) |
H5A—C5—H5B | 107.0 | C16—C17—H17 | 119.5 |
O3—C6—C13 | 105.32 (8) | C18—C17—H17 | 119.5 |
O3—C6—C7 | 110.19 (9) | C13—C18—C17 | 120.55 (12) |
C13—C6—C7 | 108.27 (10) | C13—C18—H18 | 119.7 |
O3—C6—C5 | 109.66 (10) | C17—C18—H18 | 119.7 |
C13—C6—C5 | 110.67 (9) | C2—O1—C3 | 106.33 (10) |
C7—C6—C5 | 112.48 (9) | C4—O2—C2 | 108.53 (10) |
C12—C7—C8 | 118.05 (11) | C6—O3—H1O | 105.7 (8) |
C12—C7—C6 | 121.97 (11) | ||
O1—C3—C4—O2 | −30.56 (14) | C7—C6—C13—C18 | −104.24 (13) |
O1—C2—C5—C6 | −162.39 (10) | C5—C6—C13—C18 | 19.46 (15) |
O2—C2—C5—C6 | −47.72 (14) | O3—C6—C13—C14 | −42.13 (14) |
C1—C2—C5—C6 | 76.20 (14) | C7—C6—C13—C14 | 75.73 (13) |
C2—C5—C6—O3 | 57.28 (13) | C5—C6—C13—C14 | −160.56 (10) |
C2—C5—C6—C13 | 173.04 (10) | C18—C13—C14—C15 | −0.58 (19) |
C2—C5—C6—C7 | −65.72 (14) | C6—C13—C14—C15 | 179.44 (12) |
O3—C6—C7—C12 | −4.07 (16) | C13—C14—C15—C16 | −0.1 (2) |
C13—C6—C7—C12 | −118.77 (13) | C14—C15—C16—C17 | 0.6 (2) |
C5—C6—C7—C12 | 118.62 (12) | C15—C16—C17—C18 | −0.4 (2) |
O3—C6—C7—C8 | 174.87 (10) | C14—C13—C18—C17 | 0.75 (19) |
C13—C6—C7—C8 | 60.17 (14) | C6—C13—C18—C17 | −179.28 (11) |
C5—C6—C7—C8 | −62.43 (15) | C16—C17—C18—C13 | −0.3 (2) |
C12—C7—C8—C9 | 0.7 (2) | O2—C2—O1—C3 | −29.34 (13) |
C6—C7—C8—C9 | −178.28 (12) | C1—C2—O1—C3 | −145.78 (11) |
C7—C8—C9—C10 | −0.8 (2) | C5—C2—O1—C3 | 88.33 (12) |
C8—C9—C10—C11 | 0.3 (2) | C4—C3—O1—C2 | 37.24 (14) |
C9—C10—C11—C12 | 0.4 (2) | C3—C4—O2—C2 | 13.39 (14) |
C8—C7—C12—C11 | 0.0 (2) | O1—C2—O2—C4 | 9.01 (13) |
C6—C7—C12—C11 | 178.97 (12) | C1—C2—O2—C4 | 124.92 (12) |
C10—C11—C12—C7 | −0.6 (2) | C5—C2—O2—C4 | −107.39 (12) |
O3—C6—C13—C18 | 137.90 (11) |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H1O···O2 | 0.94 (1) | 1.81 (1) | 2.6820 (12) | 153 (1) |
Experimental details
Crystal data | |
Chemical formula | C18H20O3 |
Mr | 284.34 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 173 |
a, b, c (Å) | 5.7961 (4), 8.8271 (7), 29.754 (2) |
β (°) | 92.150 (7) |
V (Å3) | 1521.26 (19) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.68 × 0.35 × 0.09 |
Data collection | |
Diffractometer | Oxford Diffraction Gemini diffractometer |
Absorption correction | Multi-scan (CrysAlis PRO; Oxford Diffraction, 2007) |
Tmin, Tmax | 0.974, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5871, 3407, 2458 |
Rint | 0.017 |
(sin θ/λ)max (Å−1) | 0.675 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.100, 1.03 |
No. of reflections | 3407 |
No. of parameters | 194 |
No. of restraints | 1 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.23, −0.19 |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2007), CrysAlis RED (Oxford Diffraction, 2007), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997), publCIF (Westrip, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H1O···O2 | 0.943 (8) | 1.808 (10) | 2.6820 (12) | 152.8 (12) |
Acknowledgements
The authors gratefully acknowledge the Applied Chemistry Cluster, Faculty of Science and Technology, Queensland University of Technology, for financial support.
References
Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115–119. Web of Science CrossRef CAS IUCr Journals Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Oxford Diffraction (2007). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England. Google Scholar
Paulson, D. R., Hartwig, A. L. & Moran, G. F. (1973). J. Chem. Ed. 50, 216–217. CrossRef CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2009). publCIF. In preparation. Google Scholar
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The molecular stucture of the title compound, (I), is illustrated in Fig. 1. There is an intramolecular hydrogen bond between the hydroxy moiety and one of the ketal oxygen atoms (O3—H1O···O2, oxygen-oxygen distance 2.6820 (12) Å, O—H···O angle 153 (1)°). The presence of the hydrogen bond results in a loss of the average mirror symmetry and as a result the molecular conformer is chiral at C2. Both hands of the conformer are present in the structure as implied by the centrosymmetric space symmetry. The 1H NMR spectrum (room temperature) is indicative of the average conformation indicating that rearrangement in the solution state is rapid on the NMR timescale.
The molecules of (I) are arranged in chains that propagate parallel to the b axis via intermolecular CH···π interactions as illustrated in Fig. 2 (C15—H15edge···C13—C18plane distance 2.96 Å). Interestingly, these are the only significant aryl-aryl interactions. The aliphatic components of the molecule including the methyl, methylene and ketal groups, completely occupy the space between the two phenyl rings (highlighted in Fig. 2) in which π interactions would be expected to occur. Adjacent chains are connected by weakly interacting aliphatic-CH···π interactions in addition to the omnipresent van der Waals forces.