Crystal structures and Hirshfeld surface analysis of a series of 4-O-aryl-perfluoro-pyridines.

Five new crystal structures of perfluoro-pyridine substituted in the 4-position with phen-oxy, 4-bromo-phen-oxy, naphthalen-2-yl-oxy, 6-bromo-naphthalen-2-yl-oxy, and 4,4'-biphen-oxy are reported, viz. 2,3,5,6-tetra-fluoro-4-phen-oxy-pyridine, C11H5F4NO (I), 4-(4-bromo-phen-oxy)-2,3,5,6-tetra-fluoro-pyridine, C11H4BrF4NO (II), 2,3,5,6-tetra-fluoro-4-[(naphthalen-2-yl)-oxy]pyridine, C15H7F4NO (III), 4-[(6-bromo-naphthalen-2-yl)-oxy]-2,3,5,6-tetra-fluoropyridine, C15H6BrF4NO (IV), and 2,2'-bis-[(perfluoro-pyridin-4-yl)-oxy]-1,1'-biphenyl, C22H8F8N2O2 (V). The dihedral angles between the aromatic ring systems in I-IV are 78.74 (8), 56.35 (8), 74.30 (7), and 64.34 (19)°, respectively. The complete mol-ecule of V is generated by a crystallographic twofold axis: the dihedral angle between the pyridine ring and adjacent phenyl ring is 80.89 (5)° and the equivalent angle between the biphenyl rings is 27.30 (5)°. In each crystal, the packing is driven by C-H⋯F inter-actions, along with a variety of C-F⋯π, C-H⋯π, C-Br⋯N, C-H⋯N, and C-Br⋯π contacts. Hirshfeld surface analysis was conducted to aid in the visualization of these various influences on the packing.