On the formation and reactivity of multinuclear silsesquioxane metal complexes

A new family of complexes, based on a general motif of four metal atoms in a μ3-oxygen surrounding has been synthesized and the reactivity was tested. Depending on the ligands on the outer (reactive) metal atoms, the reactivity ranges from very reactive towards protic and coordinating substances to completely unreactive. Based on the reaction mechanism, new heterobimetallic complexes could be synthesized, although caution should be taken regarding the ‘hardness’ of the metals. Selected complexes were tested in various catalytic reactions and were found to be inactive (Diels-Alder), active but unsuitable (lactide polymerization), or very active (ethene polymerization). Integrating the synthetic knowledge from this thesis into the relevant new developments in silsesquioxane chemistry could lead to the introduction of new and active catalysts for Lewis-acid based catalysis.