5-Methyl-1H-indole-3-carbaldehyde

Abstract

The title mol­ecule, C₁₀H₉NO, is almost planar with an r.m.s. deviation for all non-H atoms of 0.0115 Å. In the crystal, mol­ecules are connected through N—H⋯O hydrogen bonds into chains running along [021]. The chains are further connected via C—H⋯π inter­actions, forming layers in the bc plane.

Related literature  

For the structure of 1H-indole-3-carbaldehyde, see: Ng (2007 ▶) and for the structure of 6-bromo-1H-indole-3-carbaldehyde, see: Johnson et al. (2009 ▶).

Experimental  

Crystal data  

• C₁₀H₉NO

• M _r = 159.18

• Orthorhombic,

• a = 16.9456 (19) Å

• b = 5.7029 (6) Å

• c = 8.6333 (9) Å

• V = 834.31 (15) ų

• Z = 4

• Mo Kα radiation

• μ = 0.08 mm⁻¹

• T = 296 K

• 0.47 × 0.15 × 0.05 mm

Data collection  

• Bruker APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.962, T _max = 0.996

• 5499 measured reflections

• 1147 independent reflections

• 717 reflections with I > 2σ(I)

• R _int = 0.039

Refinement  

• R[F ² > 2σ(F ²)] = 0.038

• wR(F ²) = 0.107

• S = 0.98

• 1147 reflections

• 113 parameters

• 1 restraint

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.12 e Å⁻³

• Δρ_min = −0.14 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: X-SEED (Barbour, 2001 ▶); software used to prepare material for publication: SHELXL97 and publCIF (Westrip, 2010 ▶).

Supplementary Material

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

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

Cg is the centroid of the N1/C1/C2/C3/C8 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N⋯O1i	0.93 (3)	1.90 (3)	2.818 (3)	169 (3)
C9—H9⋯Cg ii	0.93	2.91	3.312 (3)	107

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

The structure of the title compound is isomorphous with that of 1H-indole-3-carbaldehyde (Ng, 2007). The planar molecules are connected via N—H···O hydrogen bonds (Table 1) into chains in the [021] direction. The chains are further linked through C—H···π interactions (Table 1) to form layers in the bc plane. The structure of 6-bromo-1H-indole-3-carbaldehyde (Johnson et al., 2009) exhibits similar N—H···O bonded chains, however, further supramolecular aggregation by Br-involved interactions is observed.

Experimental

The title crystals were obtained by slow evaporation of an ethanolic solution of the commercially available 5-methylindole-3-carboxaldehyde at room temperature.

Refinement

The C-bound hydrogen atoms were located in calculated positions and refined in a riding mode with C—H distances of 0.93 (C_sp2) and 0.96 (C_methyl) Å. The N-bound H atom was found in a difference Fourier map and refined freely. For all hydrogen atoms, U_iso were set to 1.2–1.5U_eq(carrier atom). In the absence of significant anomalous scattering effects Friedel pairs were merged.

Figures

Fig. 1.

Molecular structure of the title compound showing thermal ellipsoids at the 30% prbability level. Hydrogen spheres are drawn with an arbitrary radius.

Fig. 2.

Crystal packing view looking down the a axis, thus showing the two-dimensional-supramolecular structure formed by N—H···O and C—H···π interactions (dashed lines).

Crystal data

C10H9NO	F(000) = 336
Mr = 159.18	Dx = 1.267 Mg m−3
Orthorhombic, Pca21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2ac	Cell parameters from 1172 reflections
a = 16.9456 (19) Å	θ = 2.4–22.1°
b = 5.7029 (6) Å	µ = 0.08 mm−1
c = 8.6333 (9) Å	T = 296 K
V = 834.31 (15) Å3	Lath, yellow
Z = 4	0.47 × 0.15 × 0.05 mm

Data collection

Bruker APEXII CCD diffractometer	1147 independent reflections
Radiation source: fine-focus sealed tube	717 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.039
φ and ω scans	θmax = 28.8°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −22→13
Tmin = 0.962, Tmax = 0.996	k = −7→7
5499 measured reflections	l = −11→11

Refinement

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)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.107	H atoms treated by a mixture of independent and constrained refinement
S = 0.98	w = 1/[σ2(Fo2) + (0.0596P)2] where P = (Fo2 + 2Fc2)/3
1147 reflections	(Δ/σ)max < 0.001
113 parameters	Δρmax = 0.12 e Å−3
1 restraint	Δρmin = −0.14 e Å−3

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	0.27204 (11)	1.0610 (3)	0.6573 (2)	0.0742 (6)
N1	0.29282 (16)	0.4126 (4)	0.3481 (3)	0.0760 (7)
H1N	0.2766 (15)	0.285 (5)	0.290 (5)	0.091*
C1	0.2435 (2)	0.5303 (4)	0.4384 (3)	0.0717 (8)
H1	0.1913	0.4879	0.4563	0.086*
C2	0.27969 (14)	0.7233 (4)	0.5018 (3)	0.0587 (6)
C3	0.35916 (14)	0.7227 (4)	0.4414 (3)	0.0535 (6)
C4	0.42432 (15)	0.8710 (4)	0.4561 (3)	0.0554 (6)
H4	0.4212	1.0036	0.5185	0.066*
C5	0.49316 (16)	0.8208 (4)	0.3782 (3)	0.0638 (7)
C6	0.49673 (18)	0.6225 (5)	0.2839 (4)	0.0785 (8)
H6	0.5434	0.5904	0.2311	0.094*
C7	0.4341 (2)	0.4736 (5)	0.2661 (3)	0.0766 (8)
H7	0.4377	0.3422	0.2026	0.092*
C8	0.36502 (18)	0.5241 (4)	0.3453 (3)	0.0626 (7)
C9	0.24192 (16)	0.8851 (4)	0.6026 (3)	0.0640 (6)
H9	0.1897	0.8544	0.6292	0.077*
C10	0.56347 (18)	0.9773 (6)	0.3966 (4)	0.0860 (10)
H10A	0.5654	1.0866	0.3121	0.129*
H10B	0.6107	0.8842	0.3969	0.129*
H10C	0.5595	1.0615	0.4926	0.129*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0843 (15)	0.0640 (9)	0.0743 (12)	0.0106 (9)	0.0086 (10)	−0.0101 (9)
N1	0.109 (2)	0.0565 (10)	0.0622 (13)	−0.0129 (12)	−0.0146 (15)	−0.0053 (11)
C1	0.0820 (19)	0.0660 (13)	0.0671 (17)	−0.0143 (15)	−0.0109 (17)	0.0081 (14)
C2	0.0722 (18)	0.0533 (11)	0.0508 (12)	−0.0012 (11)	−0.0030 (12)	0.0033 (10)
C3	0.0668 (17)	0.0499 (10)	0.0440 (11)	0.0056 (10)	−0.0070 (11)	−0.0013 (10)
C4	0.0639 (16)	0.0528 (10)	0.0495 (12)	0.0026 (11)	−0.0052 (12)	−0.0003 (10)
C5	0.0640 (18)	0.0699 (14)	0.0575 (14)	0.0141 (12)	−0.0022 (13)	0.0073 (13)
C6	0.081 (2)	0.0869 (18)	0.0678 (16)	0.0295 (15)	0.0074 (16)	0.0032 (15)
C7	0.105 (2)	0.0657 (14)	0.0590 (16)	0.0237 (16)	0.0008 (17)	−0.0133 (12)
C8	0.089 (2)	0.0488 (10)	0.0502 (13)	0.0051 (12)	−0.0112 (14)	−0.0021 (11)
C9	0.0662 (17)	0.0683 (13)	0.0574 (14)	0.0083 (14)	0.0013 (13)	0.0124 (13)
C10	0.068 (2)	0.102 (2)	0.088 (2)	0.0008 (17)	0.0032 (16)	0.0136 (17)

Geometric parameters (Å, º)

O1—C9	1.221 (3)	C4—H4	0.9300
N1—C1	1.326 (4)	C5—C6	1.395 (4)
N1—C8	1.379 (4)	C5—C10	1.497 (4)
N1—H1N	0.93 (3)	C6—C7	1.368 (4)
C1—C2	1.374 (3)	C6—H6	0.9300
C1—H1	0.9300	C7—C8	1.385 (4)
C2—C9	1.421 (3)	C7—H7	0.9300
C2—C3	1.444 (3)	C9—H9	0.9300
C3—C4	1.397 (3)	C10—H10A	0.9600
C3—C8	1.408 (3)	C10—H10B	0.9600
C4—C5	1.377 (3)	C10—H10C	0.9600
C1—N1—C8	109.7 (2)	C7—C6—C5	122.3 (3)
C1—N1—H1N	121.9 (18)	C7—C6—H6	118.8
C8—N1—H1N	128.1 (18)	C5—C6—H6	118.8
N1—C1—C2	111.0 (3)	C6—C7—C8	118.1 (2)
N1—C1—H1	124.5	C6—C7—H7	121.0
C2—C1—H1	124.5	C8—C7—H7	121.0
C1—C2—C9	124.3 (3)	N1—C8—C7	131.4 (2)
C1—C2—C3	105.7 (2)	N1—C8—C3	107.3 (2)
C9—C2—C3	130.0 (2)	C7—C8—C3	121.2 (3)
C4—C3—C8	119.0 (2)	O1—C9—C2	125.6 (3)
C4—C3—C2	134.7 (2)	O1—C9—H9	117.2
C8—C3—C2	106.3 (2)	C2—C9—H9	117.2
C5—C4—C3	120.0 (2)	C5—C10—H10A	109.5
C5—C4—H4	120.0	C5—C10—H10B	109.5
C3—C4—H4	120.0	H10A—C10—H10B	109.5
C4—C5—C6	119.4 (3)	C5—C10—H10C	109.5
C4—C5—C10	119.9 (2)	H10A—C10—H10C	109.5
C6—C5—C10	120.7 (3)	H10B—C10—H10C	109.5

Hydrogen-bond geometry (Å, º)

Cg is the centroid of the N1/C1/C2/C3/C8 ring.

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O1i	0.93 (3)	1.90 (3)	2.818 (3)	169 (3)
C9—H9···Cgii	0.93	2.91	3.312 (3)	107

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