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 angstrom) makes a dihedral angle of 63.56 (8)degrees with the anthracene ring (r.m.s. deviation = 0.023 angstrom). There is a short intramolecular C-H center dot center dot center dot N interaction present, and a C-H center dot center dot center dot pi interaction involving the two ring systems. In the crystal, the indole H atom forms an intermolecular N-H center dot center dot center dot pi interaction, linking molecules to form chains along the b-axis direction. There are also C-H center dot center dot center dot pi 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.