Synthesis, crystal structure and Hirshfeld surface analysis of 2-(perfluoro-phen-yl)acetamide in comparison with some related compounds.

Anton P Novikov,Mikhail S Grigoriev,Alexey A Bezdomnikov,Konstantin E German

doi:10.1107/s2056989021013359

Abstract

The mol-ecular and crystal structures of the title compound, C8H4F5NO, were examined by single-crystal X-ray diffraction and Hirshfeld surface analysis. The title compound was synthesized by a new method at the interface of aqueous solutions of LiOH and penta-fluoro-phenyl-aceto-nitrile. In the crystal, hydrogen bonds and π-halogen inter-actions connect the mol-ecules into double layers. Analysis of the Hirshfeld surface showed that the most important contributions to the crystal packing are made by F⋯F (30.4%), C⋯F/F⋯C (22.9%), O⋯H/H⋯O (14.9%), H⋯F/F⋯H (14.0%) and H⋯H (10.2%) contacts. The Hirshfeld surfaces of analogues of the title compound were compared and the effect of perfluorination on the crystal packing was shown.

Highlights

The molecular and crystal structures of the title compound, C8H4F5NO, were examined by single-crystal X-ray diffraction and Hirshfeld surface analysis
The title compound was synthesized by a new method at the interface of aqueous solutions of LiOH and pentafluorophenylacetonitrile
Hydrogen bonds and –halogen interactions connect the molecules into double layers

Summary

Chemical context

The development of effective methods for the formation of an amide bond CONR2 is of great importance because of the high synthetic value of amides, their industrial applications and pharmacological interest (Massolo et al, 2020). We have synthesized 2–(perfluorophenyl) acetamide, 1, from pentafluorophenylacetonitrile and determined its crystal structure. We have analysed the Hirshfeld surface of this compound and compared it with those of 2-(4-chlorophenyl) acetamide, 2 (OCETAT; Ma et al, 2011) and 2-phenylacetamide, 3 (SAWHAC; Skelton et al, 2017). Symmetry codes: (i) Àx; Ày þ 2; Àz þ 1; (ii) x; Ày þ 32; z À 12 This angle is larger than in the 3-chloro-4-hydroxyphenyl acetamide (Davis et al, 2005). Torsion angles C8—C7—C1— C6 and C1—C7—C8—N2 are À74.35 (15) and 134.77 (12), respectively. This conformation is probably a consequence of intermolecular hydrogen bonds and steric factors

Structural commentary

Supramolecular features

81 Novikov et al C8H4F5NO

Findings

Synthesis and crystallization