Resorcinarenes and their derivatives : synthesis, characterization and complexation in gas phase and in solution

Abstract

The research described in this thesis focuses on the synthesis, characterization and complexation of unfunctionalized and functionalized resorcinarenes. Resorcinarenes, regarded as a common pillar in supramolecular chemistry, possess a multipurpose scaffold for various applications. The aromatic ring of resorcinarenes is highly activated for electrophilic substitutions by the presence of the hydroxyl groups. The rr-basic bowl shaped cavity in the unfunctionalized resorcinarene is mainly responsible for its ability to attract guest species. This thesis focuses on the synthesis of the core resorcinarenes with several lower rim chains, modifying the upper rim resorcinarene at the 2-position of the resorcinol ring between the two hydroxyl groups. Further functionalization of the 2-position includes the addition of halogens and chiral aminomethylated groups. Sulfonyl esterification of the phenolic hydroxyls of the resorcinarenes is also reported. The guests used in the complexation studies were either synthesized or commercially available. The guests selection ranges from cationic to neutral species. The cationic guests include chiral and non-chiral alkylammonium cations, phosphonium and metalloorganic cations. Encapsulation properties of both the unfunctionalized and functionalized resorcinarenes with the different guests were studied in detail. The size and charge of the encapsulated guests as well as the size and electronic properties of the substituents on the hosts were found to be important. Resorcinarene and pyrogallarene hexameric capsules were shown to exist in the gas phase with [Ru(2,2' -bipyridine)3]2+ acting as the template for hexameric capsule formation by virtue of its size and as it is a dication a lower m/z range was obtained. The conformation, stereochemistry, electronic and inclusion properties of the resorcinarene hosts were studied in the gas phase, liquid and solid state by mass spectrometry, NMR spectroscopy, fluorescence spectroscopy and X-ray crystallography. A brief review of resorcinarene synthesis, self-assembly and supramolecular chemistry is presented as an introduction to this thesis. The complexation and selfassembling properties of resorcinarenes via mass spectrometry, NMR spectroscopy and X-ray crystallography are reviewed.