TRÖGER´S BASE AS SCAFFOLD FOR SYNTHETIC RECEPTORS

Abstract: This work focuses on the use of the Tröger´s base as organic scaffold for the construction of synthetic receptors for different classes of organic molecules. The structural properties of the Tröger's base, i.e. chirality, rigidity and curvature, allow for synthetic modifications towards the recognition of different molecules. While the concave nature of the TB offers the geometrical frame for recognition events, the specific electronic properties of the appended binding motifs dictate the nature of the complementary molecules to be bound. In this way, the synthesis of different analogues of TB has allowed to study their affinity towards molecules as diverse as barbital, tris-L-alanine, alkyl bisammonium salts and fullerenes. This binding events have been quantified by means of NMR and fluorescence spectroscopy. Computational studies have been carried out to gain further understanding of the established interactions between the receptor and the substrate. The molecular recognition events have established the platform for the study of other processes. Thus, binding studies of different bisammonium salts have been used in an attempt to model the non-polar interactions between the aromatic side chains of natural receptors and lipophilic substituents of natural substrates. The sequential binding of metal ions to a bis-crown ether Tröger´s base analogue has been used to study the thermodynamic factors governing the observed negative cooperativity