Di‑, Tri‑, and Tetra(pentafluorophenyl) Derivatives for Oligotopic Anion−π Interactions

The
present study describes a series of pentafluorobenzyl ammonium
salts with two, three, or four C6F5 units in
order to investigate simultaneous interactions of several perfluorinated
arenes with anions in the crystalline state. Most of the structures
show multiple anion−π contacts. However, only 6·2HI reveals an effective encapsulation of the iodide ion by
the aromatic units. For comparison, the structure of 4b is investigated because it offers two π-systems with inverse
charge distribution to a bromide anion. Only the electron-deficient
π-system of the pentafluorophenyl group interacts with the anion.