Metallo-foldamers

Friday, 14 May 11:00am – 12:00pm

This seminar will be delivered via Zoom – Please email chemistry.researchsupport@sydney.edu.au for zoom link and password.

Speaker: Dr Dan Preston; Australian National University

Host: Dr Derrick Roberts

Abstract:

Foldamers are sequences that fold up into secondary structural elements dependent on the identity of the components within the sequence. Peptidic foldamers such as a-helices and b-sheets provide the scaffold by which nature is able achieve precise spatial control within its biological machinery. These structures, and abiotic analogues, are self-assembled in terms of their folding, but not in terms of construction of their primary structure or sequence. These sequences have to be synthesised in a stepwise manner: this ensures fidelity of information, but makes synthesis more difficult.

Metallosupramolecular structures are formed under thermodynamic control, and therefore theoretically a sequence can be assembled directly from a mixture of components. However, in practice to assemble a molecule with a specific sequence, components must come together at metal ion nodes in a predictable way. This talk will detail our efforts to combine mixtures of metal ions and ligands that spontaneously assemble into 1) specific sequences, which fold into 2) persistent secondary structures. We have used the principles of 3:1 and 2:2′ complementary denticity in square planar metal ions to control the process of sequence formation, while folding is driven by π-π interactions between electron rich and electron poor aromatic surfaces.

Figure 1 3:1 and 2:2′ complementary denticity with palladium(II) to create self-assembled sequences that fold into secondary structures.

Abstract: 

Dan Preston completed his undergraduate studies at the University of Otago, followed by a doctorate at the same university under the supervision of Professor James Crowley (awarded 2017). Dan was then awarded a Rutherford Postdoctoral Fellowship (2018) to carry out independent research under the mentorship of Professor Paul Kruger at the University of Canterbury (NZ). In April 2020, Dan started his independent career as a DECRA Fellow at the Research School of Chemistry at the Australian National University. His research centres on supramolecular chemistry, in the formation of structurally, functionally or behaviourally complex architectures from metal ions and organic ligands. He likes to do his chemistry in solution, working on discrete systems.