文摘

Electrospray ionization from methanolic solution can be used for the generation of the freecyclophane tetracations 1⁴⁺-3⁴⁺ from the corresponding hexafluorophosphates. In the idealized gas phase,these tetracations are long-lived and can easily be handled for further spectroscopic studies. Collision-induced dissociation of the free tetracations brings about charge separation via cleavage of the pyridiniumbonds, leading to a pair of dications. Subsequently, these dications undergo another charge separationreaction to finally afford singly charged cations. In addition to the free tetracations, also the correspondingtrications having one PF₆^- counterion are examined. Collision-induced dissociation of the trications leadsto a formal substitution reaction concomitant with C-F bond formation. Further, the catenanes of thetetracations 1⁴⁺-3⁴⁺ with bis-p-phenylene-34-crown-10 (4) are investigated. For the parent compound 1,also the gas-phase infrared spectrum is reported for the first time.