DABCO and bromoethyl-DABCO are not encapsulated inside the cavity of CB . They form coordination compounds. The carbonyl groups of one portal of CB interact with one protonated nitrogen atom of DABCO . The stability constants and thermodynamic data for the complex formation of CB with DABCO and bromomethyl-DABCO are nearly identical with results for the complexation of NH4 + in the same solvent (log K = 2.69 ± 0.03 [L mol -1 ], -ΔH = 3.9 ± 0.4 [kJ mol -1 ], TΔS = 11.4 ± 0.6 [kJ mol -1 ] [30].