Exploration of new cucurbit[n]uril and a novel glycoluril based macrocycle - tiara[n]uril.

Abstract

The successful formation of higher homologues in the case of the fully substituted CyPnQ[n] from a glycoluril bearing cyclopentane ring serves as inspiration for this thesis. Herein, we discuss the synthesis of two new functionalised and fully substituted Q[n] derivatives – cyclopentanocarboxylic acidnQ[n] (AcidCyPnQ[n]) and tetrahydrothiophenenQ[n] (THTnQ[n]) where carboxylic acid and sulphur functionality has been introduced into the cyclopentanoglycoluril moiety respectively. This provided the means to study the effect of functional groups on Q[n] homologues distribution. The synthesis of AcidCyPnQ[n] resulted in AcidCyP₅Q[5] and AcidCyP₆Q[6] but no higher homologues were present. Changes in, acid concentration, reactant concentration and template ions was found to increase only the AcidCyP₆Q[6] proportion slightly. In order to analyse the problem associated with higher homologue formation of AcidCyPnQ[n], the synthesis of THTnQ[n] was carried out. The proportion of THT₆Q[6] showed an improvement compared to AcidCyP₆Q[6], but again no higher homologues. The inability of either AcidCyPnQ[n] or THTnQ[n] to form higher homologues in their synthesis are discussed in chapter 2. In an attempt to explore the properties of the new AcidCyP₅Q[5], the binding of the gases CH₄, CH₃Cl, CH₂F₂, CH₃F were evaluated and compared with Q[5] and CyP₅Q[5]. Increases in the binding of gases across all three Q[5]’s were observed when there is an increase in K+ concentration and the reason for the increased binding has been discussed. Also comparative binding of THT₆Q[6] , CyP₆Q[6] and Me₄Q[6] with 1,4-dioxane demonstrated that binding was 10 fold higher in THT₆Q[6] compared to the other two. This thesis also reports the synthesis and a property exploration of the novel glycoluril based water soluble anionophoric macrocycle that has been named as tiara[n]uril in this thesis. This new macrocycle contains a concave wall of glycolurils and two linked pyrazoliums providing a planar facet to complete the cavity. In total, five macrocyclic derivatives (tiaraurils) have been discussed in chapter 3. In addition to the synthesis, the affinity of the host-Me₁₀TU[3] towards the zwitterions of amino acids, two tripeptides and insulin, have been demonstrated through changes in their CD spectra.