Simultaneous endo and exo Complex Formation of Pyridine[4]arene Dimers with Neutral and Anionic Guests

The formation of complexes between hexafluorophosphate (PF6−) and tetraisobutyloctahydroxypyridine[4]arene has been thoroughly studied in the gas phase (ESI‐QTOF‐MS, IM‐MS, DFT calculations), in the solid state (X‐ray crystallography), and in chloroform solution (1H, 19F, and DOSY NMR spectroscopy). In all states of matter, simultaneous endo complexation of solvent molecules and exo complexation of a PF6− anion within a pyridine[4]arene dimer was observed. While similar ternary complexes are often observed in the solid state, this is a unique example of such behavior in the gas phase. Inside or outside? The formation of noncovalent complexes between hexafluorophosphate (PF6−) and tetraisobutyloctahydroxypyridine[4]arene has been studied in the gas phase, in the solid state, and in solution. In all states of matter, simultaneous endo complexation of solvent molecules and exo complexation of PF6− anions with the pyridine[4]arene dimers was observed.