Selective formation of a coordinatively unsaturated metal complex at a surface: A SiO2-immobilized, three-coordinate ruthenium catalyst for alkene epoxidation

Article abstract of DOI:10.1002/anie.200700980

(Chemical Equation Presented) Unsaturated but air-stable: A three-coordinate Ru complex, 2, highly active for alkene epoxidation and recyclable in air, was prepared on SiO₂ by exploiting the exothermic reaction between O₂ and isobutyraldehyde (IBA) to eliminate a p-cymene ligand from a coordinatively saturated precursor 1 (Ru red, Cl dark blue, N green, S yellow, O blue, C gray, H white). In contrast, direct activation with O₂ alone was calculated to be endothermic.