Advantages of Covalent Immobilization of Metal‐Salophen on Amino‐Functionalized Mesoporous Silica in Terms of Recycling and Catalytic Activity for CO ₂ Cycloaddition onto Epoxides

NiII and MnIII Schiff base complexes (Salophen-Ni Salophen-MnCl) bearing a pending carboxylic group were prepared characterized. Both grafted onto mesoporous amino-functionalized SBA-15 silica, by formation of an amide function between the propylamine groups support acid functions salophen ligand (corresponding respective to 1.30 wt.% Ni 1.06 Mn). The co-catalytic behaviour free was then evaluated in CO2 cycloaddition reaction styrene oxide, using tetra-butylammonium bromide (n−Bu4NBr) as main catalyst. In homogeneous conditions, complex one, lesser extent, behave efficient co-catalysts for this (styrene conversion 100 % 65 respectively after 3 h at 120 °C, under 15 bars CO2). Upon immobilization surface SBA-15, we showed that activity less i. e. Ni2+ complex, could be enhanced (reaching full 7 h), hence highlighting potential synergistic effect unused amine co-catalyst. successfully re-used conditions or their without any appreciable loss activity. This work is only first step towards completely heterogeneous catalytic system, which tetraalkylammonium halide catalyst metal-salophen co-catalyst will both covalently anchored on same support.