Selwyn F. Mapolie

Title: Professor
Office: 2011 Inorganic Chemistry Building
Phone: +27 (0)21 808-2722
Fax: +27 (0)21 808-3849
E-mail

Educational Background:
PhD, University of Cape Town, 1989
Sabbaticals: University of Western Ontario (Canada) and Howard University (USA)

Awards:
Andrew Mellon Research Fellowship
Fulbright Research Fellowship

Research Emphasis:
Synthetic Organometallic Chemistry, Homogeneous Catalysis, Dendrimer Chemistry, Polymer Chemistry.

Research Summary:
The main focus of our research is the development of new multifunctional ligands which could be employed as synthons for the production of new multinuclear metal complexes. The multinuclear complexes include metallo-dendrimers as well as metal-containing polymers. These metal complexes are used as catalyst precursors in a number of organic transformations. In recent times we have also focused on the immobilization of coordination complexes on mesoporous supports such as MCM-41 and SBA-15.

Research Description:
Metallo-dendrimers: Here we have developed a series of peripheral functionalized dendrimers largely based on the polypropyleneimine architecture. Functionalities incorporated onto the periphery include salicylaldimines, pyridine-imines and pyrrole–imines. These have been used as ligands to complex to a range of metal salts to yield metallo-dendrimers. Thus we have prepared new multinuclear metal complexes of Pd, Pt, Cu, Co, Ni and Fe. Many of these metallodendrimers have been evaluated as catalyst precursors in a range of catalytic processes. Included amongst these processes are olefin oligomerization/polymerization, alkene oxidation, hydroxylation of phenol and oxidation of alcohols.

In many cases we observe a dendritic effect in which both activity and selectivity are dependent on the dendrimer generation.


Immobilized Metal Complexes: We have developed methods for immobilizing coordination complexes on mesoporous silicas such as MCM-41 and SBA-15. The metal complexes are tethered onto the inorganic support via a siloxane linkage which is attached to the ligand network. We have employed various physical techniques to characterize these immobilized complexes, including FTIR, DRUVS,
SEM, BET surface analysis and XRD. The supported complexes have been used as catalysts in oxidation reactions.

Metal-containing.polymers: We have prepared organometallic polymers using metal-containing monomers as scaffolds. These materials have the potential to be employed in a range of applications such catalysts, photoresists, sensors and non-linear optics etc. An example of a a metal containg polymer prepared in our lab is shown in the figure. Our approach has been to develop metal-containing monomers and then to polymerise these to form the corresponding macromolecule.