Dendrimers and hyperbranched polymers are highly branched polymers with a central core, branches and a periphery of terminal groups. These types of molecules are used for drug delivery, binding metal ions, homogeneous catalysis, and lots of other applications.
Polyhedral Oligomeric Silsesquioxanes (POSS) molecules are silicon-oxygen cages with the general formula [RSiO3/2]2n. The cubic silsesquioxane (the cube in the centre of the image above) has been utilized as a core for dendrimers by various research groups and is advantageous because it allows 8 branches to be attached. Conventional dendrimer cores allow for 3 or 4 branches per molecule. 8 branches lead to a higher density of terminal and internal ligand groups in fewer reactive steps which is economical both in terms of time and reagents. So we do 8 reactions at once, which makes these far simpler to make than the structures suggest.
In this project, POSS cored dendrimers will be prepared using techniques from both organic and polymer synthesis. The products will be characterized by various analytical techniques including NMR and IR. We will try to avoid column chromatography where possible but the techniques of this project will be mainly organic synthesis. Ideally we will make some molecules in the first half of the year then devise some experiments to test them for a specific application (negotiated between KJH and the student) in the second semester.
Project Workers (3rd year project students):