title: Crystal structure of dimethyl 3,3'-[(4-chloro-phen-yl)methyl-ene]bis-(1H-indole-2-carboxyl-ate).
abstract: In the title compound, C27H21ClN2O4, the mean planes of the two indole ring systems (r.m.s. deviations = 0.021 and 0.024 Å) are approximately perpendicular to one another, with a dihedral angle of 79.54 (12)°. The benzene ring is twisted with respect to the mean planes of the two indole ring systems at angles of 80.14 (15) and 86.30 (15)°. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds, forming inversion dimers with an R (2) 2(18) ring motif. The dimers are linked by a further N-H⋯O hydrogen bond, forming chains along [100]. There are intra- and inter-molecular C-H⋯π inter-actions present, the latter linking the chains to form a three-dimensional supra-molecular structure.
authors.affiliation: Chemical Engineering Department, Nanjing College of Chemical Technology, Geguan Road No.265 Nanjing, Nanjing 210048, People's Republic of China.
authors.forename: Yu-Long
authors.initials: YL
authors.lastname: Li
authors.affiliation: Chemical Engineering Department, Nanjing College of Chemical Technology, Geguan Road No.265 Nanjing, Nanjing 210048, People's Republic of China.
authors.forename: Hong-Shun
authors.initials: HS
authors.lastname: Sun
authors.affiliation: Chemical Engineering Department, Nanjing College of Chemical Technology, Geguan Road No.265 Nanjing, Nanjing 210048, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Chemical Engineering Department, Nanjing College of Chemical Technology, Geguan Road No.265 Nanjing, Nanjing 210048, People's Republic of China.
authors.forename: Ning
authors.initials: N
authors.lastname: Xu
authors.affiliation: Chemical Engineering Department, Nanjing College of Chemical Technology, Geguan Road No.265 Nanjing, Nanjing 210048, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
keywords: C—H⋯π inter­actions; MRI contrast agent; N—H⋯O hydrogen bonds; bis-indolymethane; crystal structure; indole