Crystal structures of three N-ar-yl-2,2,2-tri-bromo-acetamides.

Three N-ar-yl-2,2,2-tri-bromo-acetamides, namely, 2,2,2-tri-bromo-N-(2-fluoro-phen-yl)-acetamide, C8H5Br3FNO, (I), 2,2,2-tri-bromo-N-[3-(tri-fluoro-methyl)-phen-yl]-acetamide, C9H5Br3F3NO, (II) and 2,2,2-tri-bromo-N-(4-fluoro-phen-yl)-acetamide, C8H5Br3FNO, (III) were synthesized and their crystal structures were analysed. In the crystal structure of (I), C-Br⋯πar-yl inter-actions connect the mol-ecules into dimers, which in turn are connected via Br⋯Br contacts [3.6519 (12) Å], leading to the formation of a one-dimensional ladder-type architecture. The crystal structure of (II) features chains linked by N-H⋯O and C-H⋯O hydrogen bonds. Two such chains are inter-linked to form ribbons through Br⋯Br [3.6589 (1) Å] and Br⋯F [3.0290 (1) Å] inter-actions. C-Br⋯πar-yl and C-F⋯πar-yl inter-actions between the ribbons extend the supra-molecular architecture of (II) from one dimension to two. In (III), the mol-ecules are connected into R 2 (2)(8) dimers via pairs of C-H⋯F inter-actions and these dimers form ribbons through Br⋯Br [3.5253 (1) Å] contacts. The ribbons are further inter-linked into columns via C-Br⋯O=C contacts, forming a two-dimensional architecture.