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

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.

The title molecule, C 10 H 9 NO, 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-HÁ Á ÁO hydrogen bonds into chains running along [021]. The chains are further connected via C-HÁ Á Á interactions, forming layers in the bc plane.

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.

Computing details
Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); 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 (Sheldrick, 2008) and publCIF (Westrip, 2010   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). where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.12 e Å −3 Δρ min = −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 F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 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 (Å 2 )
x y z U iso */U eq O1 0.27204 (11