Fellows seminar - Frontiers in chemistry: "Click" chemistry for polymersomes & Dreaming of "naked" metal dications

This last Fellows seminar of the academic year will present two frontier projects with exciting results in the field of chemistry. 

Process meets chemistry: Endless possibilities

Madeline Vauthier, 2023 Fellow

In recent decades, due to the growing development of smart and eco-friendly (miniaturised) materials, polymersomes - self-assembled amphiphilic spheres that can encapsulate a liquid - are of high interest due to their stability and unique structure that resembles liposomes.

They can be obtained through different processes and devices. During the USIAS project, the work focused on the production of the smallest polymersomes based on biocompatible block copolymers in flow. Controlling their size (30 - 60 nm) and polydispersity, comparing microfluidics and batch self-assembly, was the first target of this study in order to later scaling up the process.

Two questions were subsequently tackled: is it possible to control their aggregation by external stimulation? Can we control their assembly the same way? There, process met “click” Diels-Alder chemistry to produce thermoresponsive objects able to selectively form/break covalent bonds depending on their environment. Outstanding results were obtained, confirming the potential use for various application fields. 

"Naked" earth-abundant metal dications: dream or reality? 

Rudi Wehmschulte & Samuel Dagorne, Fellows 2023

Manganese, cobalt and nickel are metals that are found in abundance on Earth, and which have important chemical qualities. These metals typically exist as positively charged particles (dications) such as Mn2+, Co2+ and Ni2+ and have, in this form, been used to facilitate (mediate) various chemical transformations over the past 80 years.

These charged metal particles are never truly "alone"; they are always associated in some way with other molecules, such as the solvent they are dissolved in or negatively charged ions. This significantly reduces their chemical reactivity (Lewis acidity), limiting their effectiveness. However, to date, nobody has managed to produce "free" or "naked" metal dications in a liquid or solid form (condensed phase), despite their fundamental interest and potential utility in various areas of applied chemistry.

This presentation will describe unprecedented approaches designed to obtain unassociated, "naked" Mn2+, Co2+ and Ni2+ dications, that interact only weakly with their environment in solution. Preliminary studies on how these isolated particles might be utilised in different areas of chemistry will also be discussed.