Crystal structure analysis of a star-shaped triazine compound: a combination of single-crystal three-dimensional electron diffraction and powder X-ray diffraction

Abstract

The solid-state structure of star-shaped 2,4,6-tris{(E)-2-[4-(dimethylamino)-phenyl]ethenyl}-1,3,5-triazine is determined from a powder sample by exploiting the respective strengths of single-crystal three-dimensional electron diffraction and powder X-ray diffraction data. The unit-cell parameters were determined from single crystal electron diffraction data. Using this information, the powder X-ray diffraction data were indexed, and the crystal structure was determined from the powder diffraction profile. The compound crystallizes in a noncentrosymmetric space group, P222. The molecular conformation in the crystal structure was used to calculate the molecular dipole moment of 3.22 Debye, which enables the material to show nonlinear optical effects.

Structure analysis of materials at the order–disorder borderline using three-dimensional electron diffraction

“…5(b)], which are 20.1 Å and 19.9 Å , respectively. Cell parameters determined by 3D ED have normally rather low precision and accuracy when compared with X-ray diffraction, with errors up to 2-5% for cell lengths and 1-2 for angles (Kolb et al, 2011;Å ngströ m et al, 2018;Gorelik et al, 2018). Additionally, reflections in ED are relatively large and possibly with a not perfectly circular shape, due to anisotropic crystal habit and intensity under-sampling or saturation.…”