Our research focuses on supramolecular chemistry, particularly the supramolecular chemistry of anions.
Specifically, we are interested in using anions to template the formation of complex, three-dimensional supramolecular systems. The development of template-directed synthesis has allowed the creation of intricate and complex systems, but nearly all of these systems rely on transition metal templates to bring together ligands and hold them in place. We are investigating whether anions can be used to assemble positively-charged ligands into similarly complex structures with novel host-guest and adsorption properties.
Specific areas of research are described in more detail below.
Switchable hydrogen bonded framework materials
We are interested in using strong hydrogen bonds between cationic receptors and anions to assemble 3D framework materials. We recently demonstrated that we could assemble these frameworks in water, and use a range of stimuli to switch between various forms of the frameworks. Since this time we have prepared a range of supramolecular frameworks using the favourable hydrogen bonding interactions between amidinium cations and carboxylate anions. We have been able to vary the framework topology and incorporate a range of functionality into the materials (e.g. porphyrin, pentiptycene, amines). We collaborate with Christan Doonan’s group (University of Adelaide) to study the gas adsorption properties of these systems.
Anion-templated assembly of cages and other complex architectures
We are investigating the use of anions to assemble large cage structures, and to order these, and other, cages into well-defined 3D superstructures. We are particularly interested in preparing overall-neutral systems so that we do not have to worry about non-coordinating anions/cations (the few anion-templated cages prepared to date have all been highly negatively-charged, necessitating the presence of a large number of non-coordinating organic cations).
Understanding dynamic self–assembly processes
Working with Megan O’Mara and Michael Thomas at ANU, we use a combination of NMR spectroscopy, molecular dynamics (MD) simulations and X-ray crystallography to understand how hydrogen bond donors and acceptors (particularly anions) interact in solution in competitive solvents. Recent work has investigated the interaction of simple benzamidinium receptors with anions in aqueous solvents, and the complex self–assembly of bisamidinium cations and dicarboxylate anions in a range of solvents. We have also looked at the dynamic processes occurring in a family of simple hydroxy anion receptors.