MOFs based on 1D structural sub-domains with Brønsted acid and redox active sites as effective bi-functional catalysts

Abstract

A novel family of lamellar MOF-type materials, which contain Brønsted acid sites together with redox active centers, based on assembled 1D organic–inorganic nanoribbons were obtained through direct solvothermal synthesis routes, using specific monotopic benzylcarboxylate spacers with thiol substituents in the para-position like structural modulator compounds and effective post-synthesis oxidized treatments to generate accessible sulfonic groups. Low-dimensional aluminum metal–organic materials, containing free sulfonic pendant groups (Al-ITQ-SO₃H), were successfully tested in several acid reactions, such as acetalization, esterification and ring opening of epoxides with a significant impact on fine chemistry processes. The direct introduction of stabilized Pd nanoparticles, cohabitating with pendant sulfonic groups, allowed the preparation of active bi-functional MOF-type hybrid materials (Al-ITQ-SO₃H/Pd) capable of carrying out one-pot two-step oxidation–acetalization reactions, exhibiting high yield and high activity during consecutive catalytic cycles.