The crystal and molecular structures of p-nitrobenzylidene-p-dimethylaminoaniline and p-dimethylaminobenzylidene-p-nitroaniline

Abstract

The crystal data for p-nitrobenzylidene-p-dimethylaminoaniline (I) are: monoclinic, space group P21/c; a = 11.065 (2), b=7.759 (2), c= 16.488 (2)/~,, fl= 10653 (3) °, Z = 4 . The crystal data for p-dimethylaminobenzylidene-p-nitroaniline (II) are: triclinic, space group P]'; a=9.509 (1), b= 16.200 (1), c= 9-505 (1) ~, e=91.69 (1), fl= 107.52 (1), 9,= 10104 (1) °, Z = 4 (two independent molecules in the asymmetric unit). The intensity data were collected on a four-circle diffractometer using Zr-filtered Mo Ke radiation. The structures were refined by a block-diagonal least-squares method to R indices of 0.081 for (I) and 0.070 for (II). The molecule (I), as a whole, is in a nearly planar conformation, and (II) in a non-planar one. The twist angles of the aniline ring out of the C-N=C-C plane are 9.2 ° for (I), and 41.5 and 49.0 ° for (II). The twist angles of the benzylidene ring range from 4.1 to 114 °.