Ni(salphen)-based metal–organic framework for the synthesis of cyclic carbonates by cycloaddition of CO2 to epoxides

Abstract

A well-defined homogeneous molecular catalyst Ni(salphen) was introduced as a ''metalloligand'' in a MOF, providing an efficient and recyclable heterogeneous catalyst for the synthesis of cyclic carbonates by the cycloaddition of CO 2 to epoxides under relatively mild conditions.

The Potential Applications of Nanoporous Materials for the Adsorption, Separation, and Catalytic Conversion of Carbon Dioxide

“…This research group has also compared the activity of selected MOF systems for the cycloaddition of CO 2 onto styrene oxide and among them, UIO-66-NH 2 MOF was found to be the most active, with 70% conversion in 1 h. [ 138 ] However, the reaction conditions remained at high pressure and temperature with the use of a toxic solvent. There are other examples showing the catalytic activity of MOFs (Ni(salphen)-MOF, [ 139 ] Mg-MOF-74, [ 140 ] ZIF-8 [ 141 ] and MIXMOF-5 [ 142 ] as catalysts for cycloaddition of CO 2 onto an epoxide. Compared with zeolite catalysts, the larger pores of MOF catalysts did promote cycloaddition of CO 2 on larger epoxides, but most of these systems were operated at high pressure (>5 atm) and temperature (100-140 °C), with quarternary ammonium ions as co-catalysts in some cases.…”

A heterometal (Pd–Pb) organic framework: synthesis, structure and heterogeneous catalytic application

“…Metal–organic frameworks (MOFs) have attracted tremendous interests and an enormous amount of MOFs have been designed and synthesized for energy‐, environment‐ and medicine‐relevant applications, such as gas sorption, luminescence, sensors and so on. Especially, MOFs used as heterogeneous catalysts have been developed dramatically during the past decade and many MOF‐based catalysts containing various types of catalytic sites have been reported . Among them, the most intensively investigated topic is MOF‐based Lewis acid catalysts that utilize the coordinatively unsaturated metal centers in MOFs.…”

“…However, these MOF catalysts often suffer from the possible collapse of frameworks after catalytic reaction since the coordinatively unsaturated metal centers are also responsible for the stability of the frameworks. To overcome this problem, a more rational strategy is to utilize metalloligands involving well‐defined catalytic sites rather than pure organic ligands to construct MOF catalysts . For example, we have reported two Ni(salen)‐based MOFs that could be used as efficient and recyclable heterogeneous catalysts for the synthesis of cyclic carbonates by the cycloaddition of CO 2 with epoxides using the Ni(salen) moieties as Lewis acid catalytic sites .…”

“…To overcome this problem, a more rational strategy is to utilize metalloligands involving well‐defined catalytic sites rather than pure organic ligands to construct MOF catalysts . For example, we have reported two Ni(salen)‐based MOFs that could be used as efficient and recyclable heterogeneous catalysts for the synthesis of cyclic carbonates by the cycloaddition of CO 2 with epoxides using the Ni(salen) moieties as Lewis acid catalytic sites . Recently, the bipyridine palladium complex Pd(H 2 bpydc)Cl 2 (H 2 bpydc = 2,2′‐bipyridine‐5,5′‐dicarboxylic acid) has been used as metalloligand to prepare MOF catalysts, such as Pd/Ln‐MOFs, Pd/Y‐MOF, doped UiO‐67 and MOF‐253, which all exhibit good heterogeneous catalytic activity for C‐C coupling reactions.…”

Bi-functional heterogeneous catalysts for carbon dioxide conversion: enhanced performances at low temperature

“…However, this goal is usually achieved employing imidazolium or more oen ammonium salts in homogeneous phase. [40][41][42][43][44][45] It should be mentioned that a direct comparison with the literature is hampered by the huge differences in the reaction conditions employed for the synthesis of cyclic carbonates including presence of solvent, substrate to catalyst molar ratio, nature of nucleophile, use of co-catalyst, temperature, pressure and reaction time. These difficulties can be partially reduced if the catalysts are compared in terms of turnover number or turnover frequency (TOF dened as TON/ time).…”