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Sodium-23 n.m.r. studies of the exchange of Na+ between the solvated and Na+·C211 environments show that the cryptate dissociation rate constant kd(335 K)= 1053.6±4.1, 832.7±5.0 and 554.8±3.2, ΔH‡= 67.2±0.3, 69.5±0.4 and 83.5±0.5 kJ mol–1 and ΔS‡= 12.6±0.7, 17.4±1.2 and 55.9±1.2 J K–1 mol–1 in water, dimethyl sulphoxide and dimethylformamide, respectively. Both 13C and 23Na n.m.r. studies indicate that Na+·C211 exists predominantly in the exclusive form in solution whereas Li+·C211 exists predominantly in the inclusive form. These data are discussed in terms of the two sequential equilibria: [graphics ommitted]. Mechanistic discussion is also extended to larger cryptates.

19 F n.m.r. studies of the inclusion of o-, m-, p- and α-fluoro-trans-cinnamates and o, p- and α,p-difluoro-trans-cinnamates by α-cyclodextrin (αCD) have shown that two inclusion equilibria [graphic omitted] are established in D2O solution at pD = 8.5 ± 0.1. Typically at 294 K, K1= 111 ± 13 dm3 mol–1 and K2= 23 ± 2 dm3 mol–1 for α,p-difluoro-trans-cinnamate. Chemical-shift and other data indicate that the predominant S·αCD complex is that in which the carboxylate group of the fluorocinnamate enters the wide end of the αCD cavity, delineated by twelve secondary hydroxy groups, first. The S·(αCD)2 complex probably has a structure in which the fluoro-trans-cinnamate is encapsulated by two αCD with the wide ends of their cavities in close proximity.