Low-temperature study of 3-acetylindole at 110 K.

The title compound, C(10)H(9)NO, contains an acetyl group that is nearly coplanar with the indole ring system, with an angle between the planes of the heterocyclic ring and the acetyl group of 1.75 (17) degrees . The planes of the benzene and pyrrole rings in the indole system make a dihedral angle of 2.05 (11) degrees . Each molecule in the unit cell is linked through N-H...O hydrogen bonds to two other molecules, forming hydrogen-bonded chains in the [101] direction with graph set C(6). The significance of this study lies in the analysis of the interactions occurring via hydrogen bonds in this structure, as well as in the comparison drawn between the molecular structure of the title compound and those of several other indole derivatives possessing a 3-carbonyl group. The correlation between the IR spectrum of this compound and the structural data is also discussed.