2-(4-Ethoxy­benzyl)­indan

Turner, A.B.; Harrison, W.T.A.

doi:10.1107/S1600536804026492

organic compounds

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ISSN: 2056-9890

Volume 60| Part 11| November 2004| Pages o2138-o2139

https://doi.org/10.1107/S1600536804026492

2-(4-Ethoxybenzyl)indan

Alan B. Turner ^a and William T. A. Harrison ^a ^*

^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), was prepared from 2-(4-ethoxybenzylidene)indan-1-one, (I), by catalytic hydrogenation over palladium/carbon. The usual product of this type of reaction is the benzylindanone (Ganellin et al., 1967 ) or the benzylindanol (Cromwell & Ayer, 1960 ), but in this case there were no carbonyl or hydroxyl absorptions in the IR spectrum of (II). The ¹³C NMR data suggested the benzylindan structure for (II), which was confirmed by the crystal structure determination described here.

All the geometrical parameters for (II) (Fig. 1) lie within their expected ranges (Allen et al., 1995 ). 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 π–π interactions in (II) and the crystal packing is controlled by van der Waals forces (Fig. 2).

Figure 1
View of (II

) (50% displacement ellipsoids and H atoms drawn as small spheres of arbitrary radius).

Figure 2
Unit-cell packing in (II

), 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 ) 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) (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
M_r = 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
D_x = 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 ) T_min = 0.985, T_max = 0.997
15379 measured reflections
2604 independent reflections
1259 reflections with I > 2σ(I)
R_int = 0.256
θ_max = 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(F_o²) + (0.0752P)² + 0.112P] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max < 0.001
Δρ_max = 0.24 e Å⁻³
Δρ_min = −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 R_int. 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 U_iso(H) = 1.2U_eq(C) or 1.5U_eq(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 ); 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: ORTEP3 (Farrugia, 1997 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks II, global. DOI: https://doi.org/10.1107/S1600536804026492/bt6549sup1.cif

Structure factors: contains datablock II. DOI: https://doi.org/10.1107/S1600536804026492/bt6549IIsup2.hkl

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

C₁₈H₂₀O	F(000) = 544
M_r = 252.34	D_x = 1.193 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3361 reflections
a = 16.5624 (12) Å	θ = 2.9–27.5°
b = 5.6290 (3) Å	µ = 0.07 mm⁻¹
c = 16.3266 (14) Å	T = 120 K
β = 112.610 (4)°	Rod, colourless
V = 1405.14 (17) Å³	0.22 × 0.06 × 0.04 mm
Z = 4

Data collection top

Nonius KappaCCD diffractometer	2604 independent reflections
Radiation source: fine-focus sealed tube	1259 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.256
ω and φ scans	θ_max = 25.5°, θ_min = 3.0°
Absorption correction: multi-scan (SADABS; Bruker, 1999)	h = −20→19
T_min = 0.985, T_max = 0.997	k = −6→6
15379 measured reflections	l = −19→18

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)] = 0.089	H-atom parameters constrained
wR(F²) = 0.211	w = 1/[σ²(F_o²) + (0.0752P)² + 0.112P] where P = (F_o² + 2F_c²)/3
S = 1.02	(Δ/σ)_max < 0.001
2604 reflections	Δρ_max = 0.24 e Å⁻³
174 parameters	Δρ_min = −0.27 e Å⁻³
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction 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

	x	y	z	U_iso*/U_eq
C1	0.3190 (3)	0.0259 (8)	0.4491 (3)	0.0399 (13)
H1A	0.2825	−0.1172	0.4364	0.060*
H1B	0.3417	0.0489	0.4024	0.060*
H1C	0.2839	0.1640	0.4512	0.060*
C2	0.3947 (2)	−0.0021 (7)	0.5377 (3)	0.0338 (11)
H2A	0.3726	−0.0206	0.5857	0.041*
H2B	0.4295	−0.1445	0.5371	0.041*
C3	0.5209 (2)	0.2181 (6)	0.6295 (3)	0.0268 (10)
C4	0.5430 (2)	0.0529 (7)	0.6966 (3)	0.0295 (11)
H4	0.5063	−0.0803	0.6922	0.035*
C5	0.6207 (2)	0.0840 (7)	0.7718 (3)	0.0300 (11)
H5	0.6360	−0.0303	0.8181	0.036*
C6	0.6753 (2)	0.2753 (7)	0.7804 (3)	0.0275 (10)
C7	0.6505 (2)	0.4409 (7)	0.7118 (3)	0.0328 (12)
H7	0.6866	0.5757	0.7167	0.039*
C8	0.5749 (2)	0.4147 (7)	0.6366 (3)	0.0333 (12)
H8	0.5597	0.5291	0.5903	0.040*
C9	0.7600 (2)	0.3054 (7)	0.8602 (3)	0.0284 (11)
H9A	0.7593	0.1989	0.9082	0.034*
H9B	0.7638	0.4709	0.8819	0.034*
C10	0.8412 (2)	0.2505 (6)	0.8403 (3)	0.0259 (10)
H10	0.8375	0.3465	0.7874	0.031*
C11	0.8510 (2)	−0.0146 (6)	0.8193 (3)	0.0277 (11)
H11A	0.8307	−0.1215	0.8556	0.033*
H11B	0.8181	−0.0501	0.7557	0.033*
C12	0.9491 (2)	−0.0373 (6)	0.8442 (3)	0.0238 (10)
C13	0.9952 (2)	−0.2116 (7)	0.8208 (3)	0.0261 (10)
H13	0.9654	−0.3406	0.7840	0.031*
C14	1.0860 (2)	−0.1946 (7)	0.8520 (3)	0.0278 (11)
H14	1.1182	−0.3138	0.8365	0.033*
C15	1.1299 (2)	−0.0081 (6)	0.9051 (3)	0.0292 (11)
H15	1.1919	0.0006	0.9258	0.035*
C16	1.0835 (2)	0.1677 (6)	0.9283 (3)	0.0274 (11)
H16	1.1135	0.2980	0.9641	0.033*
C17	0.9930 (2)	0.1519 (6)	0.8990 (3)	0.0242 (10)
C18	0.9283 (2)	0.3113 (6)	0.9165 (3)	0.0244 (10)
H18A	0.9435	0.4808	0.9147	0.029*
H18B	0.9257	0.2761	0.9749	0.029*
O1	0.44753 (16)	0.2072 (5)	0.5520 (2)	0.0345 (9)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.027 (2)	0.044 (3)	0.044 (3)	−0.0006 (19)	0.008 (2)	0.000 (2)
C2	0.025 (2)	0.039 (2)	0.037 (3)	−0.0065 (18)	0.013 (2)	−0.002 (2)
C3	0.023 (2)	0.025 (2)	0.032 (3)	0.0053 (17)	0.011 (2)	0.0022 (19)
C4	0.026 (2)	0.029 (2)	0.033 (3)	0.0004 (17)	0.011 (2)	−0.0025 (19)
C5	0.029 (2)	0.029 (2)	0.036 (3)	−0.0008 (17)	0.016 (2)	0.0003 (19)
C6	0.024 (2)	0.028 (2)	0.030 (3)	0.0016 (18)	0.0095 (19)	−0.0003 (19)
C7	0.026 (2)	0.030 (2)	0.039 (3)	−0.0053 (18)	0.009 (2)	0.001 (2)
C8	0.031 (2)	0.026 (2)	0.040 (3)	0.0046 (18)	0.012 (2)	0.0044 (19)
C9	0.026 (2)	0.028 (2)	0.032 (3)	−0.0009 (17)	0.012 (2)	0.0019 (19)
C10	0.023 (2)	0.025 (2)	0.026 (3)	−0.0005 (17)	0.0050 (18)	0.0014 (18)
C11	0.024 (2)	0.031 (2)	0.028 (3)	−0.0032 (17)	0.0099 (19)	−0.0008 (19)
C12	0.028 (2)	0.019 (2)	0.026 (2)	−0.0002 (16)	0.0120 (18)	0.0019 (17)
C13	0.030 (2)	0.023 (2)	0.024 (3)	−0.0028 (17)	0.0100 (19)	0.0018 (18)
C14	0.028 (2)	0.026 (2)	0.032 (3)	0.0037 (17)	0.014 (2)	0.0084 (19)
C15	0.022 (2)	0.030 (2)	0.034 (3)	0.0026 (18)	0.008 (2)	0.006 (2)
C16	0.028 (2)	0.024 (2)	0.028 (3)	−0.0068 (17)	0.008 (2)	−0.0029 (18)
C17	0.026 (2)	0.020 (2)	0.027 (3)	0.0006 (16)	0.0109 (19)	0.0006 (16)
C18	0.024 (2)	0.023 (2)	0.025 (3)	−0.0030 (16)	0.0082 (18)	0.0012 (17)
O1	0.0266 (15)	0.0303 (16)	0.038 (2)	−0.0045 (12)	0.0030 (14)	0.0048 (13)

Geometric parameters (Å, º) top

C1—C2	1.514 (6)	C9—H9B	0.9900
C1—H1A	0.9800	C10—C18	1.538 (5)
C1—H1B	0.9800	C10—C11	1.554 (5)
C1—H1C	0.9800	C10—H10	1.0000
C2—O1	1.433 (4)	C11—C12	1.522 (5)
C2—H2A	0.9900	C11—H11A	0.9900
C2—H2B	0.9900	C11—H11B	0.9900
C3—C4	1.376 (6)	C12—C13	1.384 (5)
C3—O1	1.378 (5)	C12—C17	1.401 (5)
C3—C8	1.399 (5)	C13—C14	1.394 (5)
C4—C5	1.407 (5)	C13—H13	0.9500
C4—H4	0.9500	C14—C15	1.377 (5)
C5—C6	1.378 (5)	C14—H14	0.9500
C5—H5	0.9500	C15—C16	1.393 (5)
C6—C7	1.393 (6)	C15—H15	0.9500
C6—C9	1.512 (5)	C16—C17	1.389 (5)
C7—C8	1.384 (6)	C16—H16	0.9500
C7—H7	0.9500	C17—C18	1.508 (5)
C8—H8	0.9500	C18—H18A	0.9900
C9—C10	1.532 (5)	C18—H18B	0.9900
C9—H9A	0.9900

C2—C1—H1A	109.5	C9—C10—C11	114.5 (3)
C2—C1—H1B	109.5	C18—C10—C11	104.3 (3)
H1A—C1—H1B	109.5	C9—C10—H10	107.8
C2—C1—H1C	109.5	C18—C10—H10	107.8
H1A—C1—H1C	109.5	C11—C10—H10	107.8
H1B—C1—H1C	109.5	C12—C11—C10	102.3 (3)
O1—C2—C1	107.4 (3)	C12—C11—H11A	111.3
O1—C2—H2A	110.2	C10—C11—H11A	111.3
C1—C2—H2A	110.2	C12—C11—H11B	111.3
O1—C2—H2B	110.2	C10—C11—H11B	111.3
C1—C2—H2B	110.2	H11A—C11—H11B	109.2
H2A—C2—H2B	108.5	C13—C12—C17	120.6 (3)
C4—C3—O1	124.9 (3)	C13—C12—C11	129.1 (3)
C4—C3—C8	120.2 (4)	C17—C12—C11	110.2 (3)
O1—C3—C8	114.9 (3)	C12—C13—C14	118.8 (4)
C3—C4—C5	119.0 (4)	C12—C13—H13	120.6
C3—C4—H4	120.5	C14—C13—H13	120.6
C5—C4—H4	120.5	C15—C14—C13	121.2 (4)
C6—C5—C4	122.0 (4)	C15—C14—H14	119.4
C6—C5—H5	119.0	C13—C14—H14	119.4
C4—C5—H5	119.0	C14—C15—C16	119.9 (4)
C5—C6—C7	117.5 (4)	C14—C15—H15	120.0
C5—C6—C9	122.0 (4)	C16—C15—H15	120.0
C7—C6—C9	120.4 (3)	C17—C16—C15	119.7 (3)
C8—C7—C6	121.9 (4)	C17—C16—H16	120.1
C8—C7—H7	119.1	C15—C16—H16	120.1
C6—C7—H7	119.1	C16—C17—C12	119.7 (4)
C7—C8—C3	119.3 (4)	C16—C17—C18	130.4 (3)
C7—C8—H8	120.3	C12—C17—C18	110.0 (3)
C3—C8—H8	120.3	C17—C18—C10	103.2 (3)
C6—C9—C10	113.2 (4)	C17—C18—H18A	111.1
C6—C9—H9A	108.9	C10—C18—H18A	111.1
C10—C9—H9A	108.9	C17—C18—H18B	111.1
C6—C9—H9B	108.9	C10—C18—H18B	111.1
C10—C9—H9B	108.9	H18A—C18—H18B	109.1
H9A—C9—H9B	107.7	C3—O1—C2	117.0 (3)
C9—C10—C18	114.2 (3)

O1—C3—C4—C5	179.2 (4)	C17—C12—C13—C14	−0.6 (6)
C8—C3—C4—C5	−0.5 (6)	C11—C12—C13—C14	−179.9 (4)
C3—C4—C5—C6	0.2 (6)	C12—C13—C14—C15	−0.2 (6)
C4—C5—C6—C7	0.6 (6)	C13—C14—C15—C16	0.0 (6)
C4—C5—C6—C9	−178.3 (4)	C14—C15—C16—C17	1.0 (6)
C5—C6—C7—C8	−1.1 (7)	C15—C16—C17—C12	−1.8 (6)
C9—C6—C7—C8	177.9 (4)	C15—C16—C17—C18	177.9 (4)
C6—C7—C8—C3	0.8 (7)	C13—C12—C17—C16	1.6 (6)
C4—C3—C8—C7	0.0 (6)	C11—C12—C17—C16	−178.9 (4)
O1—C3—C8—C7	−179.6 (4)	C13—C12—C17—C18	−178.2 (4)
C5—C6—C9—C10	105.4 (5)	C11—C12—C17—C18	1.3 (5)
C7—C6—C9—C10	−73.5 (5)	C16—C17—C18—C10	160.0 (4)
C6—C9—C10—C18	172.3 (3)	C12—C17—C18—C10	−20.3 (4)
C6—C9—C10—C11	−67.5 (4)	C9—C10—C18—C17	156.4 (3)
C9—C10—C11—C12	−155.2 (3)	C11—C10—C18—C17	30.6 (4)
C18—C10—C11—C12	−29.6 (4)	C4—C3—O1—C2	−5.5 (6)
C10—C11—C12—C13	−162.6 (4)	C8—C3—O1—C2	174.1 (4)
C10—C11—C12—C17	18.0 (4)	C1—C2—O1—C3	−179.7 (4)

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