Click on silica: systematic immobilization of Co(ii)Schiff bases to the mesoporous silicavia click reaction and their catalytic activity for aerobic oxidation of alcohols

Abstract

The systematic immobilization of cobalt(II) Schiff base complexes on SBA-15 mesoporous silica via copper catalyzed [3 + 2] azide–alkyne cycloaddition (CuAAC) “click reaction” involving either step-wise synthesis of silica-bound Schiff base ligand followed by its subsequent complexation with cobalt ions, or by the direct immobilization of preformed Co(II) Schiff base complex to the silica support is described. The catalytic activity of the prepared complexes was studied for the oxidation of alcohols to carbonyl compounds using molecular oxygen as oxidant. The immobilized complexes were recycled for several runs without loss in catalytic activity and no leaching was observed during this course.