Sulfonatocalixarenes, like other ionic receptors, possess counterions that can affect the molecular recognition process. In the present review it is shown that the competitive effect of the alkaline cations frequently used as counterions determines not only the magnitude of the external guest association constant, but also the stoichiometry of the complexes. Experimental evidences are shown about the interaction of the counterions with sulfonatocalixarene, allowing to quantify its association equilibrium constants. The counterions recognition will be a competitive process that must be taken into account when investigating the interaction of calixarenes with an external guests. When the external guest is a neutral molecule it will be possible to form ternary complexes where the counterion shows a competitive and cooperative effect. By increasing the size of the receptor, sulfonatocalix and sulfonatocalixarene, the complexity of the system is increased due to the formation of counterion complexes with stoichiometries 1:1 and 1:2. In the presence of an external guest, the formation of heteroternary complexes with 1:1:1 stoichiometries including a counterion and an organic cation will be possible.
|Journal||Pure and Applied Chemistry|
|Early online date||31 May 2019|
|Publication status||E-pub ahead of print - 31 May 2019|
|Event||24th IUPAC International Conference on Physical Organic Chemistry (ICPOC 24) - Faro, Portugal|
Duration: 1 Jul 2018 → 6 Jul 2018
- host-guest chemistry
- supramolecular chemistry