Wang J, Bartsch R. A, Thermodynamics of alkali metal cation complexation by ionised calixcrown ligands. Supramolecular Chemistry, 2014 26(7-8): 526-529

摘要

Binding of alkali metal cations (AMCs) by 1,3-alternate, ionised calix[4]arene-benzocrown-6 ligands was investigated by isothermal calorimetric titration in methanol. The groups of -C(O)NHSO₂CH₃ and more acidic -C(O)NHSO₂CF₃ were attached to the 1,3-alternate calix[4]arene-benzocrown-6 skeleton in two locations. In one series, the acidic group was attached to the para position of one aromatic ring in the calixarene framework, thereby positioning it over the polyether cavity. In the other series, the ionisable group was a substituent on the benzo group in the polyether ring. This oriented the acidic group away from the crown ether cavity. For these calixcrown ligands, the effects of the location of the ionisable group and its acidity and the identity of the AMC on the binding constant, enthalpy and entropy of complexation are assessed.