Crystal structure and DFT study of (E)-N-[2-(1H-indol-3-yl)ethyl]-1-(anthracen-9-yl)methanimine

Abstract

The title compound, C25H20N2, (I), was synthesized from the condensation reaction of anthracene-9-carbaldehyde and tryptamine in dry ethanol. The indole ring system (r.m.s. deviation = 0.016 Å) makes a dihedral angle of 63.56 (8)° with the anthracene ring (r.m.s. deviation = 0.023 Å). There is a short intramolecular C—H...N interaction present, and a C—H...π interaction involving the two ring systems. In the crystal, the indole H atom forms an intermolecular N—H...π interaction, linking molecules to form chains along the b-axis direction. There are also C—H...π interactions present, involving the central and terminal rings of the anthracene unit, linking the chains to form an overall two-dimensional layered structure, with the layers parallel to the bc plane. The density functional theory (DFT) optimized structure, at the B3LYP/6-311 G(d,p) level, is compared with the experimentally determined molecular structure in the solid state.

Keywords

• crystal structure
• anthracene
• indole
• Schiff base
• tryptamine
• methanamine
• N—H...π interactions
• C—H...π interactions