engleski

Complex equilibrium systems in supramolecular chemistry – „A blessing or a curse?”

As the field of supramolecular chemistry evolves, the systems based on non-covalent interactions find their application in various technologies as chemical sensors, transport systems etc. Consequently, it is of paramount importance to understand the thermodynamics of supramolecular reactions, which enables fine- tuning the properties of the corresponding supramolecules. To this end, the processes leading to their formation should be fully characterised and ever-new interactions stabilising the corresponding systems ought to be discovered. The reactions yielding supramolecular complexes in solution are often coupled with other processes, e.g. proton transfer, aggregation, homoassociation and ion pairing, especially in organic media. These reactions have rarely been taken into account in the course of complex characterisation, although ignoring them could lead to incomplete conclusions and erroneous interpretation of the results. In order to avoid this, it is necessary to carry out systematic identification and characterisation of all processes taking place in the solution. This often demands significant efforts, including innovative use of experimental techniques and elaborate data processing. In this lecture, several classes of anion binding hosts (urea, amine and amide derivatives) will be presented with a thorough overview of the methodology used for a complete characterisation of multiple equilibria occurring in the solutions containing the hosts and their anionic guests. With this respect, special emphasis will be on acid-base equilibria of the aforementioned ligands and several common, and biologically important anions (e.g. chloride, dihydrogen phosphate, acetate). Moreover, the aim of the lecture is to demonstrate that the extra work and time invested in such integrated approach is worthwhile, as it can provide invaluable insight in the behaviour of supramolecular systems, possibly leading to original approach of their further design.

Proton transfer ; urea derivatives ; thermodynamic characterisation ; anion binding

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