1-Vinyl-1H-indole-3-carbaldehyde

Abstract

In the title compound, C₁₁H₉NO, the C and O atoms of the attached carbaldehyde group deviate by just 0.052 (2) and 0.076 (1) Å, respectively, from the mean plane of the indole ring system. In addition to van der Waals forces, the mol­ecular packing is stabilized by C—H⋯O hydrogen bonds, which form a C(7) chain motif, and π–π inter­actions (centroid–centroid distance 3.637 Å) between the pyrrole and benzene rings of the indole ring system.

Related literature

For related literature, see: Padwa et al. (1999 ▶); Mathiesen et al. (2005 ▶); Grinev et al. (1984 ▶); Gadaginamath & Patil (1999 ▶); Rodriguez et al. (1985 ▶); Karthick et al. (2005 ▶); Selvanayagam et al. (2005 ▶); Sonar et al. (2005 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

• C₁₁H₉NO

• M _r = 171.19

• Monoclinic,

• a = 8.3200 (5) Å

• b = 8.1490 (5) Å

• c = 13.1620 (7) Å

• β = 99.952 (1)°

• V = 878.95 (9) ų

• Z = 4

• Mo Kα radiation

• μ = 0.08 mm⁻¹

• T = 293 (2) K

• 0.24 × 0.22 × 0.20 mm

Data collection

• Bruker SMART APEX CCD area-detector diffractometer

• Absorption correction: none

• 9730 measured reflections

• 2072 independent reflections

• 1823 reflections with I > 2σ(I)

• R _int = 0.020

Refinement

• R[F ² > 2σ(F ²)] = 0.044

• wR(F ²) = 0.127

• S = 1.05

• 2072 reflections

• 118 parameters

• H-atom parameters constrained

• Δρ_max = 0.21 e Å⁻³

• Δρ_min = −0.19 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and PLATON (Spek, 2003 ▶); software used to prepare material for publication: SHELXL97 and PARST (Nardelli, 1995 ▶).

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C9—H9⋯O1i	0.93	2.51	3.390 (2)	159

Symmetry code: (i) .

supplementary crystallographic information

Comment

Indoles and their derivatives have been interest for many years, since large number of natural products contain indole systems and they are found in a number of pharmaceutical products, fragrances and dyes (Padwa et al., 1999). Indole derivatives are identified as interfering with a G protein-independent signaling pathway of the CRTH2 receptor (Mathiesen et al., 2005). These derivatives possess antidepressant (Grinev et al., 1984), anti-microbial (Gadaginamath & Patil, 1999) and anti-inflammatory (Rodriguez et al., 1985) activities. In view of its importance, we have undertaken the single-crystal X-ray diffraction study and report here its results.

The X-ray study confirmed the molecular structure and atomic connectivity for (I), as illustrated in Fig. 1. The geometry of the indole ring system is comparable to those reported for other indole derivatives (Karthick et al., 2005; Selvanayagam et al., 2005; Sonar et al., 2005). The bond length of C9—C10 [1.284 (2) Å] confirms the double bond character (Allen et al., 1987). The sum of the angles at N1 of the indole ring (360°) is in accordance with sp² hybridization.

The indole ring is planar with a maximum deviation of 0.017 (1) Å for atom C8. The carbaldehyde group atoms C11 and O1 deviate 0.052 (2) and 0.076 (1) Å, respectively from the best plane of the indole ring.

In addition to the van der Waals forces, the molecular packing is stabilized by intermolecular C—H···O hydrogen bond (Table 2). Atom H9 of C9 forms a intermolecular hydrogen bond with oxygen atom O1 forming a C(7) chain motif of C—H···O hydrogen bond along the diagonal of ac plane (Fig. 2). In addition to this a weak π···π interaction between the pyrrole ring (N1/C1/C6—C8) at (x,y,z) and benzene ring (C1—C6) at (1 -x, -y), -z) stabilizes the molecular packing. The centroid-to-centroid distance is 3.637Å.

Experimental

A mixture of N-vinylindole (0.05 mol) and DMF (0.15 mol) was stirred with POCl₃ (32.3 ml). The reaction mixture was poured into ice water (300 ml) and stirred for 30minutes at less than 10° C. The precipitated solid was collected by filtration and washed well water (100 ml). In order to get the diffraction quality crystals, the compound was recrystallized from ethyl acetate.

Refinement

The H atoms were positioned geometrically with C—H distances of 0.93 Å and were included in the refinement in the riding motion approximation with U_iso= 1.2U_eq(C).

Figures

Fig. 1.

The structure and atom-numbering scheme for the title compound; displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radius.

Fig. 2.

Molecular packing of the title compound viewed down the b axis; H-bonds are shown as dashed lines. For clarity, H atoms, not involved in hydrogen bonds, have been omitted.

Crystal data

C11H9NO	F000 = 360
Mr = 171.19	Dx = 1.294 Mg m−3
Monoclinic, P21/n	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 4554 reflections
a = 8.3200 (5) Å	θ = 2.1–23.6º
b = 8.1490 (5) Å	µ = 0.08 mm−1
c = 13.1620 (7) Å	T = 293 (2) K
β = 99.952 (1)º	Block, colourless
V = 878.95 (9) Å3	0.24 × 0.22 × 0.20 mm
Z = 4

Data collection

Bruker SMART APEX CCD area-detector diffractometer	1823 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.020
Monochromator: graphite	θmax = 28.0º
T = 293(2) K	θmin = 3.0º
ω scans	h = −10→10
Absorption correction: none	k = −10→10
9730 measured reflections	l = −17→16
2072 independent reflections

Refinement

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)] = 0.044	H-atom parameters constrained
wR(F2) = 0.127	w = 1/[σ2(Fo2) + (0.0665P)2 + 0.1375P] where P = (Fo2 + 2Fc2)/3
S = 1.05	(Δ/σ)max < 0.001
2072 reflections	Δρmax = 0.21 e Å−3
118 parameters	Δρmin = −0.19 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction correction: none

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.81283 (15)	0.20464 (18)	−0.13362 (9)	0.0826 (4)
N1	0.41791 (12)	0.24005 (13)	0.07004 (7)	0.0469 (3)
C1	0.54641 (14)	0.14623 (13)	0.12226 (8)	0.0424 (3)
C2	0.56155 (16)	0.06833 (16)	0.21713 (9)	0.0505 (3)
H2	0.4800	0.0748	0.2572	0.061*
C3	0.70276 (18)	−0.01899 (17)	0.24918 (10)	0.0581 (3)
H3	0.7166	−0.0736	0.3121	0.070*
C4	0.82544 (17)	−0.02764 (17)	0.18966 (11)	0.0594 (4)
H4	0.9197	−0.0870	0.2139	0.071*
C5	0.80997 (15)	0.04980 (16)	0.09564 (10)	0.0527 (3)
H5	0.8925	0.0434	0.0563	0.063*
C6	0.66781 (14)	0.13815 (13)	0.06061 (8)	0.0431 (3)
C7	0.60762 (15)	0.23003 (15)	−0.03148 (9)	0.0480 (3)
C8	0.45684 (16)	0.28725 (16)	−0.02188 (9)	0.0503 (3)
H8	0.3901	0.3497	−0.0712	0.060*
C9	0.27187 (17)	0.27412 (19)	0.10596 (12)	0.0615 (4)
H9	0.2701	0.2521	0.1751	0.074*
C10	0.14066 (19)	0.3327 (2)	0.05257 (15)	0.0779 (5)
H10A	0.1365	0.3567	−0.0169	0.094*
H10B	0.0498	0.3511	0.0834	0.094*
C11	0.68162 (19)	0.2565 (2)	−0.12120 (11)	0.0621 (4)
H11	0.6233	0.3191	−0.1742	0.075*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0720 (7)	0.1185 (10)	0.0649 (7)	0.0021 (6)	0.0336 (6)	0.0075 (6)
N1	0.0474 (5)	0.0518 (6)	0.0428 (5)	0.0032 (4)	0.0110 (4)	−0.0026 (4)
C1	0.0457 (6)	0.0418 (5)	0.0396 (5)	−0.0022 (4)	0.0075 (4)	−0.0069 (4)
C2	0.0595 (7)	0.0521 (7)	0.0417 (6)	−0.0035 (5)	0.0136 (5)	−0.0023 (5)
C3	0.0707 (8)	0.0549 (7)	0.0464 (6)	0.0007 (6)	0.0035 (6)	0.0051 (5)
C4	0.0562 (7)	0.0544 (7)	0.0641 (8)	0.0080 (6)	0.0011 (6)	0.0007 (6)
C5	0.0475 (6)	0.0527 (7)	0.0591 (7)	0.0000 (5)	0.0129 (5)	−0.0070 (5)
C6	0.0472 (6)	0.0418 (6)	0.0411 (5)	−0.0053 (4)	0.0102 (4)	−0.0072 (4)
C7	0.0543 (7)	0.0486 (6)	0.0425 (6)	−0.0046 (5)	0.0124 (5)	−0.0023 (5)
C8	0.0566 (7)	0.0513 (7)	0.0427 (6)	0.0017 (5)	0.0079 (5)	0.0021 (5)
C9	0.0564 (8)	0.0736 (9)	0.0586 (8)	0.0089 (6)	0.0209 (6)	−0.0013 (6)
C10	0.0580 (9)	0.0892 (12)	0.0894 (12)	0.0170 (8)	0.0205 (8)	0.0036 (9)
C11	0.0670 (8)	0.0743 (9)	0.0481 (7)	−0.0059 (7)	0.0185 (6)	0.0041 (6)

Geometric parameters (Å, °)

O1—C11	1.2079 (19)	C5—C6	1.3933 (17)
N1—C8	1.3610 (16)	C5—H5	0.9300
N1—C1	1.3949 (15)	C6—C7	1.4390 (17)
N1—C9	1.4055 (16)	C7—C8	1.3645 (18)
C1—C2	1.3869 (16)	C7—C11	1.4393 (18)
C1—C6	1.4023 (16)	C8—H8	0.9300
C2—C3	1.3760 (19)	C9—C10	1.284 (2)
C2—H2	0.9300	C9—H9	0.9300
C3—C4	1.392 (2)	C10—H10A	0.9300
C3—H3	0.9300	C10—H10B	0.9300
C4—C5	1.3751 (19)	C11—H11	0.9300
C4—H4	0.9300
C8—N1—C1	108.24 (10)	C5—C6—C1	119.20 (11)
C8—N1—C9	126.55 (12)	C5—C6—C7	134.39 (11)
C1—N1—C9	125.17 (11)	C1—C6—C7	106.40 (10)
C2—C1—N1	129.57 (11)	C8—C7—C6	106.95 (10)
C2—C1—C6	122.48 (11)	C8—C7—C11	123.72 (13)
N1—C1—C6	107.94 (10)	C6—C7—C11	129.29 (12)
C3—C2—C1	116.91 (12)	N1—C8—C7	110.46 (11)
C3—C2—H2	121.5	N1—C8—H8	124.8
C1—C2—H2	121.5	C7—C8—H8	124.8
C2—C3—C4	121.60 (12)	C10—C9—N1	126.30 (15)
C2—C3—H3	119.2	C10—C9—H9	116.8
C4—C3—H3	119.2	N1—C9—H9	116.8
C5—C4—C3	121.31 (12)	C9—C10—H10A	120.0
C5—C4—H4	119.3	C9—C10—H10B	120.0
C3—C4—H4	119.3	H10A—C10—H10B	120.0
C4—C5—C6	118.49 (12)	O1—C11—C7	125.68 (15)
C4—C5—H5	120.8	O1—C11—H11	117.2
C6—C5—H5	120.8	C7—C11—H11	117.2
C8—N1—C1—C2	−178.34 (12)	N1—C1—C6—C7	−0.32 (12)
C9—N1—C1—C2	−0.3 (2)	C5—C6—C7—C8	178.96 (13)
C8—N1—C1—C6	0.77 (13)	C1—C6—C7—C8	−0.24 (13)
C9—N1—C1—C6	178.86 (12)	C5—C6—C7—C11	1.3 (2)
N1—C1—C2—C3	178.96 (11)	C1—C6—C7—C11	−177.94 (13)
C6—C1—C2—C3	−0.04 (18)	C1—N1—C8—C7	−0.95 (14)
C1—C2—C3—C4	0.56 (19)	C9—N1—C8—C7	−179.00 (12)
C2—C3—C4—C5	−0.6 (2)	C6—C7—C8—N1	0.73 (14)
C3—C4—C5—C6	0.0 (2)	C11—C7—C8—N1	178.60 (12)
C4—C5—C6—C1	0.47 (17)	C8—N1—C9—C10	11.7 (3)
C4—C5—C6—C7	−178.65 (12)	C1—N1—C9—C10	−166.00 (16)
C2—C1—C6—C5	−0.47 (17)	C8—C7—C11—O1	−178.09 (15)
N1—C1—C6—C5	−179.66 (10)	C6—C7—C11—O1	−0.7 (3)
C2—C1—C6—C7	178.87 (10)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C9—H9···O1i	0.93	2.51	3.390 (2)	159

Symmetry codes: (i) x−1/2, −y+1/2, z+1/2.