Surface OrganoMetallic Chemistry affords heterogeneous catalysts able to perform selective chemical transformations, by grafting organometallic species on surface hydroxyls of oxide supports. Past studies have focused on the modification of the coordination sphere of the grafted complex to be adjusted to the desired catalytic reaction. Moreover, the support has long been known to act as a ligand in these systems, and the podality of the grafted organometallic moiety strongly affects the resulting catalytic properties. Siloxane p-coordination at the metallic centres leads to various configurations of surface species and affect the unicity of sites obtained on the surface, which may prove detrimental to their catalytic properties. Novel organometallic surface species can be envisaged by inserting a spacer moiety, between the organometallic fragment and the surface, thus preventing any unwanted interaction. Aromatic compounds were more specifically chosen as spacers due to their large size, rigidity and inertness toward the metal; moreover they can be easily modified in order to change the electrophilicity or the steric hindrance at the metal centre. Hence, new silica supported, a single-site phenolic function was synthesized, thus providing a new support for SOMC on oxides. It was subsequently reacted with organometallic complexes. Dramatic improvements in terms of activity and stability were observed in olefin metathesis by supported molybdenum imido or tungsten oxo-carbene, olefin polymerization by supported zirconium complexes when compared to previously reported silica counterparts (eg. figure  1).

Design and application of a hybrid material featuring well-defined, tuneable grafting sites for supported catalysis

248th National Meeting (2014)

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