Crystal structures and Hirshfeld surface analysis of a series of 4-O-arylperfluoropyridines

Abstract

Five new crystal structures of perfluoropyridine substituted in the 4-position with phenoxy, 4-bromophenoxy, naphthalen-2-yloxy, 6-bromonaphthalen-2-yloxy, and 4,4′-biphenoxy are reported, viz. 2,3,5,6-tetrafluoro-4-phenoxypyridine, C11H5F4NO (I), 4-(4-bromophenoxy)-2,3,5,6-tetrafluoropyridine, C11H4BrF4NO (II), 2,3,5,6-tetrafluoro-4-[(naphthalen-2-yl)oxy]pyridine, C15H7F4NO (III), 4-[(6-bromonaphthalen-2-yl)oxy]-2,3,5,6-tetrafluoropyridine, C15H6BrF4NO (IV), and 2,2′-bis[(perfluoropyridin-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 molecule 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 interactions, 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.

Perfluoropyridine as an Efficient, Tunable Scaffold for Bis(pyrazol‐1‐yl)pyridine Copper Complexes

“…Numerous examples of 4-substituted perfluoropyridines are reported in the literature. For this study, in addition to the previously reported addition of naphthalen-2-ol [14] and phenylmagnesium chloride, [15] two other common heteroatom nucleophiles were chosen: pyrrolidine and naphthalen-2-thiol. The additions of both compounds to perfluoropyridine proceed readily under aqueous conditions with K 2 CO 3 as a base.…”

Protecting Group-Controlled Remote Regioselective Electrophilic Aromatic Halogenation Reactions

“…The TFP group was also found to be stable to a wide range of commonly employed reaction conditions . Unlike most of its alternatives, the TFP group has somewhat of a unique position as being a phenol-protecting group, which is highly electron deficient. − Due to this, we envisaged that a TFP-protected phenol would be less reactive in electrophilic substitution reactions (S E Ar) compared with either free phenols, alkyl ether-protected phenols (e.g., −OMe), or even nonphenolic rings (e.g., benzene). If this was indeed found to be the case, the reactivity difference afforded by TFP protection would provide a straightforward route to differentiate and regioselectively modify a specific ring in systems where multiple aromatic rings were present (Scheme b).…”