Crystal Structure of Zwitterionic (E)-9-(((3-hydroxyphenyl)iminio)methyl)-1,2,3,5,6,7- Hexahydropyrido[3,2,1-ij]Quinolin-8-Olate

Abstract

The title compound (1), C19H20N2O2, crystallized with single molecule in the asymmetric unit and is present in the zwitterionic form. The compound was synthesized from the condensation reaction of 8-hydroxyjulolidine-9-carbaldehyde and 3-aminophenol. In solid state compound adopts the keto–amine tautomeric form, with the H atom attached to the N atom, which participates in an intramolecular N—H···O hydrogen bond with an S(6) ring motif. The conformation about the C=N bond is E. The aromatic ring of the julolidine moiety is inclined to the phenol ring by 13.00 (10)°. The fused non-aromatic rings of the julolidine moiety adopts a screw-boat conformations. In the crystal, the molecules are connected by N—H···O and O—H···O hydrogen bonds, with adjacent molecules related by a 21 screw axis, generating– A–B–A–B–zigzag chains extending along [010]. Furthermore, adjacent molecules are linked by pairs of C—H···O interactions, forming a ladder-like structure propagating along the a-axis direction. Density functional theory (DFT) optimized structures at the B3LYP/6–311 G(d,p) level is compared with the experimentally determined molecular structure in the solid state.