The formation and characterization of molecular capsules resulting from the self-assembly between oppositely charged (thia)calixarenes in polar solvents like MeOH and MeOH–H2O are reported. The multiple ionic interactions allow the self-assembly of the complementary (thia)calixarenes 1 and 2a–d into 11 complexes as revealed by 1H NMR and mass spectrometry (ESI-MS). Isothermal titration calorimetry (ITC) was used to determine the association constants, which, depending on the ionic groups involved in the complexes, vary between 103 and 106 M–1. An X-ray structure of the assembly 1 2d was also obtained. Unlike in solution, in the solid state 1 2d forms a 11 three-dimensional network in which 2d adopts a 1,2-alternate conformation.
Corbellini, F., van Leeuwen, F. W. B., Beijleveld, H., Kooijman, H., Spek, A. L., Verboom, W., ... Reinhoudt, D. N. (2005). Multiple ionic interactions for noncovalent synthesis of molecular capsules in polar solar. New journal of chemistry, 2(1), 242-253. https://doi.org/10.1039/b412409j