Stimuli-responsive Calix[4]pyrrole and Calix[4]arene Based Receptorsfrom Unimolecular to Dimeric Structures

Abstract

This thesis describes the synthesis, dimerization and binding studies of responsive decorated synthetic receptors. The receptors are based on calix[4]arene and calix[4]pyrrole architectures, which are able to interact with charged and neutral molecules. Photo- and acidochromic properties of the responsive tetra-urea receptors were investigated in polar media (DMSO, DMF and THF) by means of UV-Vis and NMR spectroscopy. Dimerization studies were carried out in chlorinated solvents in the presence of a suitable guest and analyzed by NMR spectroscopy. Self-sorting studies with the decorated receptors demonstrate the exclusive formation of the hetero-dimeric capsule in the presence of an N-oxide guest. Disassembly/assembly of the dimeric capsules was achieved upon acid-base treatment. Finally, we describe the synthesis of photo-responsive unimolecular C[4]P receptors. Binding studies of the responsive decorated C[4]P were performed in dichloromethane and acetone by means of NMR and ITC experiments. The evaluation of anion transport across a model lipid membrane of the synthetic receptors was tested by means of fluorometric assays (HPTS and Lucigenin).