Figure 2. One-pot self-assembly of dynamic cryptate [Na⁺⊂o-Me₂-1.1.1]BArF⁻.

Partial ¹H NMR spectra (400 MHz, CDCl₃, 298 K) showing the evolution of the dynamic system over time (see Supplementary Fig. 1 for full spectra). (a) Starting materials. (b) Complex mixture that forms rapidly after addition of acid catalyst (1 h). (c) After 5 days [Na⁺⊂o-Me₂-1.1.1]BArF⁻ is formed as major product, alongside hydrolysis product MeOAc (singlets at 3.6 and 2.0 p.p.m.). (d) The crude product is obtained by removal of MeOAc under reduced pressure. (e) Further purification is conveniently achieved by passing the crude product through a short plug of silica gel. Reaction conditions: trimethyl orthoacetate (120 μmol), diethylene glycol (180 μmol), NaBArF (60 μmol), TFA (3.0 μmol; added over 5 days), MS (4 Å, 1 g), CDCl₃ (6.0 ml), 5 days, room temperature.