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2-(4-Eth­oxy­benzyl)­indan

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aDepartment of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland
*Correspondence e-mail: w.harrison@abdn.ac.uk

(Received 18 October 2004; accepted 19 October 2004; online 30 October 2004)

The title compound, C18H20O, arose as an unexpected hydrogenation product. All its geometrical parameters are normal and the crystal packing is controlled by van der Waals forces.

Comment

The title compound, (II[link]), was prepared from 2-(4-ethoxy­benzyl­idene)­indan-1-one, (I[link]), by catalytic hydrogenation over palladium/carbon. The usual product of this type of reaction is the benzyl­indanone (Ganellin et al., 1967[Ganellin, C. R., Loynes, J. M., Ridley, H. F. & Spickett, R. G. W. (1967). J. Med. Chem. 10, 826-833.]) or the benzyl­indanol (Cromwell & Ayer, 1960[Cromwell, W. H. & Ayer, R. P. (1960). J. Am. Chem. Soc. 82, 133-141.]), but in this case there were no carbonyl or hydroxyl absorptions in the IR spectrum of (II[link]). The 13C NMR data suggested the benzyl­indan structure for (II[link]), which was confirmed by the crystal structure determination described here.[link]

[Scheme 1]

All the geometrical parameters for (II[link]) (Fig. 1[link]) lie within their expected ranges (Allen et al., 1995[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1995). International Tables for Crystallography, Vol. C, section 9. 5, pp. 685-706. Dordrecht: Kluwer Academic Publishers.]). The five-membered ring (C10, C11, C12, C17 and C18) adopts an envelope conformation, with C10 at the flap position, displaced by 0.494 (7) Å from the least-squares plane through the other four C atoms [r.m.s. deviation = 0.006 Å and maximum = 0.007 (3) for C17]. There are no ππ interactions in (II[link]) and the crystal packing is controlled by van der Waals forces (Fig. 2[link]).

[Figure 1]
Figure 1
View of (II[link]) (50% displacement ellipsoids and H atoms drawn as small spheres of arbitrary radius).
[Figure 2]
Figure 2
Unit-cell packing in (II[link]), projected along the b axis, with all H atoms omitted for clarity.

Experimental

A solution of 2-(4-ethoxy­benzyl­idene)­indan-1-one (0.12 g) (Watson et al., 1993[Watson, G. J. R., Turner, A. B. & Allen, S. (1993). Organic Materials for Non-linear Optics III, edited by G. J. Ashwell and D. Bloor, RSC Special Publication No. 137, pp. 112-117. London: Royal Society of Chemistry.]) in ethanol (10 ml) containing 10% Pd/C (0.04 g) was shaken under an atmosphere of hydrogen at 293 K for 6 h. Evaporation of the ethanol after removal of the catalyst gave (II[link]) (0.08 g, 70%) as a colourless oil, which slowly solidified. It was recrystallized from ethyl acetate/hexane (1:4) to yield colourless crystals (m.p. 331–333 K). 13C NMR (100 MHz): δ 14.9, 38.9, 40.7, 41.7, 63.4, 114.3, 124.5, 126.0, 129.7, 133.4, 143.3 and 157.2.

Crystal data
  • C18H20O

  • Mr = 252.34

  • Monoclinic, P21/c

  • a = 16.5624 (12) Å

  • b = 5.6290 (3) Å

  • c = 16.3266 (14) Å

  • β = 112.610 (4)°

  • V = 1405.14 (17) Å3

  • Z = 4

  • Dx = 1.193 Mg m−3

  • Mo Kα radiation

  • Cell parameters from 3361 reflections

  • θ = 2.9–27.5°

  • μ = 0.07 mm−1

  • T = 120 (2) K

  • Rod, colourless

  • 0.22 × 0.06 × 0.04 mm

Data collection
  • Nonius KappaCCD diffractometer

  • ω and φ scans

  • Absorption correction: multi-scan (SADABS; Bruker, 1999[Bruker (1999). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.985, Tmax = 0.997

  • 15379 measured reflections

  • 2604 independent reflections

  • 1259 reflections with I > 2σ(I)

  • Rint = 0.256

  • θmax = 25.5°

  • h = −20 → 19

  • k = −6 → 6

  • l = −19 → 18

Refinement
  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.089

  • wR(F2) = 0.211

  • S = 1.02

  • 2604 reflections

  • 174 parameters

  • H-atom parameters constrained

  • w = 1/[σ2(Fo2) + (0.0752P)2 + 0.112P] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max < 0.001

  • Δρmax = 0.24 e Å−3

  • Δρmin = −0.27 e Å−3

  • Extinction correction: SHELXL97

  • Extinction coefficient: 0.023 (4)

Table 1
Selected torsion angles (°)

O1—C3—C4—C5 179.2 (4)
C6—C9—C10—C18 172.3 (3)
C6—C9—C10—C11 −67.5 (4)
C4—C3—O1—C2 −5.5 (6)
C1—C2—O1—C3 −179.7 (4)

Diffraction quality was poor, as reflected in the very high merging R factor of 0.256 and the high proportion (52%) of `unobserved' [I < 2σ(I)] reflections, even at 120 K. Merging equivalent reflections assuming only triclinic symmetry resulted in similar values for Rint. All H atoms were placed in calculated positions (C—H = 0.95–0.99 Å) and refined as riding on their carrier atoms. For all H atoms, the constraint Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl C) was applied as appropriate. The methyl group was allowed to rotate about the C1—C2 bond as a rigid group.

Data collection: COLLECT (Nonius, 1998[Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr and R. M. Sweet, pp. 307-326. New York: Academic Press.]); data reduction: HKL DENZO (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr and R. M. Sweet, pp. 307-326. New York: Academic Press.]), SCALEPACK and SORTAV (Blessing, 1995[Blessing, R. H. (1995). Acta Cryst. A51, 33-38.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); molecular graphics: ORTEP3 (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: SHELXL97.

Supporting information


Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO (Otwinowski & Minor, 1997), SCALEPACK and SORTAV (Blessing, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

2-(4-Ethoxybenzyl)indan top
Crystal data top
C18H20OF(000) = 544
Mr = 252.34Dx = 1.193 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3361 reflections
a = 16.5624 (12) Åθ = 2.9–27.5°
b = 5.6290 (3) ŵ = 0.07 mm1
c = 16.3266 (14) ÅT = 120 K
β = 112.610 (4)°Rod, colourless
V = 1405.14 (17) Å30.22 × 0.06 × 0.04 mm
Z = 4
Data collection top
Nonius KappaCCD
diffractometer
2604 independent reflections
Radiation source: fine-focus sealed tube1259 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.256
ω and φ scansθmax = 25.5°, θmin = 3.0°
Absorption correction: multi-scan
(SADABS; Bruker, 1999)
h = 2019
Tmin = 0.985, Tmax = 0.997k = 66
15379 measured reflectionsl = 1918
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.089H-atom parameters constrained
wR(F2) = 0.211 w = 1/[σ2(Fo2) + (0.0752P)2 + 0.112P]
where P = (Fo2 + 2Fc2)/3
S = 1.02(Δ/σ)max < 0.001
2604 reflectionsΔρmax = 0.24 e Å3
174 parametersΔρmin = 0.27 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.023 (4)
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
xyzUiso*/Ueq
C10.3190 (3)0.0259 (8)0.4491 (3)0.0399 (13)
H1A0.28250.11720.43640.060*
H1B0.34170.04890.40240.060*
H1C0.28390.16400.45120.060*
C20.3947 (2)0.0021 (7)0.5377 (3)0.0338 (11)
H2A0.37260.02060.58570.041*
H2B0.42950.14450.53710.041*
C30.5209 (2)0.2181 (6)0.6295 (3)0.0268 (10)
C40.5430 (2)0.0529 (7)0.6966 (3)0.0295 (11)
H40.50630.08030.69220.035*
C50.6207 (2)0.0840 (7)0.7718 (3)0.0300 (11)
H50.63600.03030.81810.036*
C60.6753 (2)0.2753 (7)0.7804 (3)0.0275 (10)
C70.6505 (2)0.4409 (7)0.7118 (3)0.0328 (12)
H70.68660.57570.71670.039*
C80.5749 (2)0.4147 (7)0.6366 (3)0.0333 (12)
H80.55970.52910.59030.040*
C90.7600 (2)0.3054 (7)0.8602 (3)0.0284 (11)
H9A0.75930.19890.90820.034*
H9B0.76380.47090.88190.034*
C100.8412 (2)0.2505 (6)0.8403 (3)0.0259 (10)
H100.83750.34650.78740.031*
C110.8510 (2)0.0146 (6)0.8193 (3)0.0277 (11)
H11A0.83070.12150.85560.033*
H11B0.81810.05010.75570.033*
C120.9491 (2)0.0373 (6)0.8442 (3)0.0238 (10)
C130.9952 (2)0.2116 (7)0.8208 (3)0.0261 (10)
H130.96540.34060.78400.031*
C141.0860 (2)0.1946 (7)0.8520 (3)0.0278 (11)
H141.11820.31380.83650.033*
C151.1299 (2)0.0081 (6)0.9051 (3)0.0292 (11)
H151.19190.00060.92580.035*
C161.0835 (2)0.1677 (6)0.9283 (3)0.0274 (11)
H161.11350.29800.96410.033*
C170.9930 (2)0.1519 (6)0.8990 (3)0.0242 (10)
C180.9283 (2)0.3113 (6)0.9165 (3)0.0244 (10)
H18A0.94350.48080.91470.029*
H18B0.92570.27610.97490.029*
O10.44753 (16)0.2072 (5)0.5520 (2)0.0345 (9)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.027 (2)0.044 (3)0.044 (3)0.0006 (19)0.008 (2)0.000 (2)
C20.025 (2)0.039 (2)0.037 (3)0.0065 (18)0.013 (2)0.002 (2)
C30.023 (2)0.025 (2)0.032 (3)0.0053 (17)0.011 (2)0.0022 (19)
C40.026 (2)0.029 (2)0.033 (3)0.0004 (17)0.011 (2)0.0025 (19)
C50.029 (2)0.029 (2)0.036 (3)0.0008 (17)0.016 (2)0.0003 (19)
C60.024 (2)0.028 (2)0.030 (3)0.0016 (18)0.0095 (19)0.0003 (19)
C70.026 (2)0.030 (2)0.039 (3)0.0053 (18)0.009 (2)0.001 (2)
C80.031 (2)0.026 (2)0.040 (3)0.0046 (18)0.012 (2)0.0044 (19)
C90.026 (2)0.028 (2)0.032 (3)0.0009 (17)0.012 (2)0.0019 (19)
C100.023 (2)0.025 (2)0.026 (3)0.0005 (17)0.0050 (18)0.0014 (18)
C110.024 (2)0.031 (2)0.028 (3)0.0032 (17)0.0099 (19)0.0008 (19)
C120.028 (2)0.019 (2)0.026 (2)0.0002 (16)0.0120 (18)0.0019 (17)
C130.030 (2)0.023 (2)0.024 (3)0.0028 (17)0.0100 (19)0.0018 (18)
C140.028 (2)0.026 (2)0.032 (3)0.0037 (17)0.014 (2)0.0084 (19)
C150.022 (2)0.030 (2)0.034 (3)0.0026 (18)0.008 (2)0.006 (2)
C160.028 (2)0.024 (2)0.028 (3)0.0068 (17)0.008 (2)0.0029 (18)
C170.026 (2)0.020 (2)0.027 (3)0.0006 (16)0.0109 (19)0.0006 (16)
C180.024 (2)0.023 (2)0.025 (3)0.0030 (16)0.0082 (18)0.0012 (17)
O10.0266 (15)0.0303 (16)0.038 (2)0.0045 (12)0.0030 (14)0.0048 (13)
Geometric parameters (Å, º) top
C1—C21.514 (6)C9—H9B0.9900
C1—H1A0.9800C10—C181.538 (5)
C1—H1B0.9800C10—C111.554 (5)
C1—H1C0.9800C10—H101.0000
C2—O11.433 (4)C11—C121.522 (5)
C2—H2A0.9900C11—H11A0.9900
C2—H2B0.9900C11—H11B0.9900
C3—C41.376 (6)C12—C131.384 (5)
C3—O11.378 (5)C12—C171.401 (5)
C3—C81.399 (5)C13—C141.394 (5)
C4—C51.407 (5)C13—H130.9500
C4—H40.9500C14—C151.377 (5)
C5—C61.378 (5)C14—H140.9500
C5—H50.9500C15—C161.393 (5)
C6—C71.393 (6)C15—H150.9500
C6—C91.512 (5)C16—C171.389 (5)
C7—C81.384 (6)C16—H160.9500
C7—H70.9500C17—C181.508 (5)
C8—H80.9500C18—H18A0.9900
C9—C101.532 (5)C18—H18B0.9900
C9—H9A0.9900
C2—C1—H1A109.5C9—C10—C11114.5 (3)
C2—C1—H1B109.5C18—C10—C11104.3 (3)
H1A—C1—H1B109.5C9—C10—H10107.8
C2—C1—H1C109.5C18—C10—H10107.8
H1A—C1—H1C109.5C11—C10—H10107.8
H1B—C1—H1C109.5C12—C11—C10102.3 (3)
O1—C2—C1107.4 (3)C12—C11—H11A111.3
O1—C2—H2A110.2C10—C11—H11A111.3
C1—C2—H2A110.2C12—C11—H11B111.3
O1—C2—H2B110.2C10—C11—H11B111.3
C1—C2—H2B110.2H11A—C11—H11B109.2
H2A—C2—H2B108.5C13—C12—C17120.6 (3)
C4—C3—O1124.9 (3)C13—C12—C11129.1 (3)
C4—C3—C8120.2 (4)C17—C12—C11110.2 (3)
O1—C3—C8114.9 (3)C12—C13—C14118.8 (4)
C3—C4—C5119.0 (4)C12—C13—H13120.6
C3—C4—H4120.5C14—C13—H13120.6
C5—C4—H4120.5C15—C14—C13121.2 (4)
C6—C5—C4122.0 (4)C15—C14—H14119.4
C6—C5—H5119.0C13—C14—H14119.4
C4—C5—H5119.0C14—C15—C16119.9 (4)
C5—C6—C7117.5 (4)C14—C15—H15120.0
C5—C6—C9122.0 (4)C16—C15—H15120.0
C7—C6—C9120.4 (3)C17—C16—C15119.7 (3)
C8—C7—C6121.9 (4)C17—C16—H16120.1
C8—C7—H7119.1C15—C16—H16120.1
C6—C7—H7119.1C16—C17—C12119.7 (4)
C7—C8—C3119.3 (4)C16—C17—C18130.4 (3)
C7—C8—H8120.3C12—C17—C18110.0 (3)
C3—C8—H8120.3C17—C18—C10103.2 (3)
C6—C9—C10113.2 (4)C17—C18—H18A111.1
C6—C9—H9A108.9C10—C18—H18A111.1
C10—C9—H9A108.9C17—C18—H18B111.1
C6—C9—H9B108.9C10—C18—H18B111.1
C10—C9—H9B108.9H18A—C18—H18B109.1
H9A—C9—H9B107.7C3—O1—C2117.0 (3)
C9—C10—C18114.2 (3)
O1—C3—C4—C5179.2 (4)C17—C12—C13—C140.6 (6)
C8—C3—C4—C50.5 (6)C11—C12—C13—C14179.9 (4)
C3—C4—C5—C60.2 (6)C12—C13—C14—C150.2 (6)
C4—C5—C6—C70.6 (6)C13—C14—C15—C160.0 (6)
C4—C5—C6—C9178.3 (4)C14—C15—C16—C171.0 (6)
C5—C6—C7—C81.1 (7)C15—C16—C17—C121.8 (6)
C9—C6—C7—C8177.9 (4)C15—C16—C17—C18177.9 (4)
C6—C7—C8—C30.8 (7)C13—C12—C17—C161.6 (6)
C4—C3—C8—C70.0 (6)C11—C12—C17—C16178.9 (4)
O1—C3—C8—C7179.6 (4)C13—C12—C17—C18178.2 (4)
C5—C6—C9—C10105.4 (5)C11—C12—C17—C181.3 (5)
C7—C6—C9—C1073.5 (5)C16—C17—C18—C10160.0 (4)
C6—C9—C10—C18172.3 (3)C12—C17—C18—C1020.3 (4)
C6—C9—C10—C1167.5 (4)C9—C10—C18—C17156.4 (3)
C9—C10—C11—C12155.2 (3)C11—C10—C18—C1730.6 (4)
C18—C10—C11—C1229.6 (4)C4—C3—O1—C25.5 (6)
C10—C11—C12—C13162.6 (4)C8—C3—O1—C2174.1 (4)
C10—C11—C12—C1718.0 (4)C1—C2—O1—C3179.7 (4)
 

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1995). International Tables for Crystallography, Vol. C, section 9. 5, pp. 685–706. Dordrecht: Kluwer Academic Publishers.  Google Scholar
First citationBruker (1999). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationBlessing, R. H. (1995). Acta Cryst. A51, 33–38.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationCromwell, W. H. & Ayer, R. P. (1960). J. Am. Chem. Soc. 82, 133–141.  CrossRef CAS Web of Science Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationGanellin, C. R., Loynes, J. M., Ridley, H. F. & Spickett, R. G. W. (1967). J. Med. Chem. 10, 826–833.  CrossRef CAS PubMed Web of Science Google Scholar
First citationNonius (1998). COLLECT. Nonius BV, Delft, The Netherlands.  Google Scholar
First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr and R. M. Sweet, pp. 307–326. New York: Academic Press.  Google Scholar
First citationSheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.  Google Scholar
First citationWatson, G. J. R., Turner, A. B. & Allen, S. (1993). Organic Materials for Non-linear Optics III, edited by G. J. Ashwell and D. Bloor, RSC Special Publication No. 137, pp. 112–117. London: Royal Society of Chemistry.  Google Scholar

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