Salen‐decorated Periodic Mesoporous Organosilica: From Metal‐assisted Epoxidation to Metal‐free CO2 Insertion. Issue 15 (19th June 2021)

• Record Type: Journal Article
• Authors: Haghighat, Mahdieh; Leus, Karen; Shirini, Farhad; Van Der Voort, Pascal
• Is Part Of: Chemistry, an Asian journal. Volume 16:Issue 15(2021)
• Page Start: 2126
• Page End: 2135
• Publication Date: 2021-06-19
• Subjects: Cyclic carbonate -- Carbon dioxide -- Epoxidation -- Salen ligand -- Thiol-ene click reaction -- Metal-free catalyst; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/asia.202100524
• Languages: English
• ISSNs: 1861-4728

Abstract

Abstract: We clicked a salen ligand onto a thiol‐ethane bridged periodic mesoporous organosilica (Salen‐PMO) using a photo‐initiated thiol‐ene click reaction. This process resulted in a covalently bonded salen ligand on the PMO material. The final BET surface area amounts 511 m 2 /g and the pore size diameter is approximately 7 nm. The functionalized PMO material showed an excellent carbon dioxide uptake capacity of 1.29 mmol/g at 273 K and 1 bar. More importantly, by coordinating a MoO2 2+ complex onto the Salen‐PMO material, we obtained a heterogeneous catalyst with a good catalytic performance for the epoxidation of cyclohexene. The catalyst was highly reusable, as no decrease in its activity was observed for at least four runs (99% conversion). Finally, the metal‐free Salen‐PMO showed an exceptional catalytic performance in the cycloaddition of CO2 to epoxides. The obtained results clearly demonstrate the versatility of the Salen‐PMO material not only as metal‐free catalyst but also as a support material to anchor metal complexes for specific catalytic applications. With the same catalytic platform, we were able to firstly create epoxides out of alkenes, and subsequently turn these epoxides into cyclic carbonates, consuming CO2 . Abstract : A PMO material decorated with salen ligand (Salen‐PMO) was developed using a photo‐initiated thiol‐ene click reaction. The resulted material was further functionalized with MoO2 2+ ion as well (Mo‐Salen‐PMO). The Mo‐Salen‐PMO and Salen‐PMO materials demonstrated excellent catalytic potential in the epoxidation of cyclohexene and in the preparation of cyclic carbonate, respectively.