Iron complex immobilized catalyst based on β-ketiminate ligand: Alkene oxygenation activity depending on the morphology of silica support and the structures of base additives

Novel immobilized iron complex catalysts based on a β-ketiminate ligand have been developed. Dehydrative condensation between β-diketone and the ethylenediamine derivative of silane-coupling reagent yields the silanol ester of the ligand motif which can be anchored on the silica supports through covalent bond. The morphology of the silica supports affects the structures of active sites and catalytic activities on alkene oxygenation with H2O2. The ordered flat surface of SBA-15 allows to immobilize the ligand with highly-dispersion and to form the coordinatively unsaturated iron active site. Addition of small amount of pyrazoles improves the catalytic performance without leaching of iron.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (159 K)Download as PowerPoint slideHighlights► Immobilized catalysts based on an iron complex of NNO-β-ketiminate are developed. ► Morphology of the supports affects the structures of active sites and activities. ► Addition of pyrazoles improves the catalytic performance without leaching of iron.