Exploitable results Supramolecular chemistry based on heterocalixarenes A new type of supramolecular receptors resembling the conventional calixarenes in the basket-shaped macrocyclic structure but comprising the benzimidazol-2-one unit as a characteristic heterocyclic construction element instead of the phenol group has been designed. Synthetic pathways for preparation of compounds have been developed and successfully applied to yield prototypical examples of the new heterocalixarene class of host molecules involving macrocycles of different ring sizes and containing four to nine aromatic and hetero-aromatic building units in variable sequence. Due to their particular structure, they form crystalline host-guest inclusions with organic solvents showing selectivity and stoichiometric behaviour. X-ray crystal structures of a series of representative inclusion compounds have been studied demonstrating the formation of endo and endo/exo singular and mixed guest inclusion complexes. The host molecule, in almost each case, is in a perfect or nearly perfect cone or closed cavity conformation, thus illustrating the possibility of transferring the structural behaviour of conventional calix(4)arenes, i.e. cage forming ability, to calix(8)arene systems using this types of heterocalix construction. Nevertheless, the present molecules are inherently mobile enough to adopt the structures demanded by different guests resulting in obviously more suitable hosts for molecular encapsulation that traditional calix(8)arenes. Development of closed basket-like host shapes for these molecules seems also being connected with base-stacking interactions involving the hetero-unit. Thus it is concluded that the unusual activity of the benzimidazole-2-one moiety renders it a particularly interesting building block for new calix frameworks, not only due to its ability to stabilise large ring dimensions, but also for its enhanced co-operativity in interactions with guest molecules, preparing the ground for many potential uses in supramolecular science such as compound separation and retrieval, shielding and stabilisation, retardation and control, activation and sensing or the design of functional self-assembling nano-structures. Initial results being promising into these directions are in hand. B> Searching for OpenAIRE data... There was an error trying to search data from OpenAIRE No results available
