High-Resolution NMR Studies of Nano-Cages

This thesis concerns the NMR investigations of supramolecular metallo-nanocages as hosts for host-guest chemistry. The research is based on metallo-nanocages constructed from cyclotriveratrylene (CTV)-derivatives
The host-guest interaction between the [Pd6(L1)8]⋅12(BF4) stella octangula cage and sodium alkyl sulfate guests have been characterised by 1H 1 D, DOSY and 2-D ROESY NMR and ESI-MS. The host-guest stoichiometry was determined at 1:2 by Job’s plot analysis. The shorter the length of the guest’s alkyl tail, the more tightly bound it was to the host cage. The self-assembly and self-sorting of the [Pd6(L1)8]⋅12(BF4) stella octangula cage were also investigated. d6-DMSO competed with the L1 ligand for the palladium(II) cation. The rate of self-sorting of the [Pd6(L1)8]⋅12(BF4) stella octangula cage was found to be affected by concentration, with lower concentrations resulting in cage systems that self-sorted in to homochiral cages at a faster rate.
The novel FL1 ligand was characterised by 1H and 19F NMR spectroscopy in d6 DMSO and d3 MeCN and was used to produce stella octangula cage assemblies. The self-assembly of this system in d6 DMSO was observed and found to require an excess of palladium to form. This FL1 system was also investigated for host-guest interactions with sodium dodecyl sulfate (SDS). It formed a system that exhibited weaker binding than L1. The FL1 ligand formed quantitative cages in d3 MeCN. This system was characterised by 1H and 19F NMR spectroscopy, 2-D ROESY NMR, ESI-MS and X-ray crystallography.
The L1 and FL1 ligands were used to form cryptophanes with [1,3 bis(diphenylphosphino)propane] in d6 DMSO, d3 MeCN and d3 MeNO2. These were characterised by 1H, 19F, 31P NMR spectroscopy, 2-D ROESY NMR, ESI-MS and X-ray crystallography. Both ligands showed a strong preference for anti cryptophane isomers in solution, although a small amount of syn isomer was observed in the L1 systems. The syn isomer was predominant species in the solid state.