Thermally activated bipyridyl-based Mn-MOFs with Lewis acid–base bifunctional sites for highly efficient catalytic cycloaddition of CO₂ with epoxides and Knoevenagel condensation reactions

Abstract

Metal-organic frameworks (MOFs) have become preferred heterogeneous catalytic materials for many reactions due to their advantages such as porosity and abundant active sites. Here, a 3D Mn-MOF-1 [Mn2(DPP)(H2O)3]·6H2O (DPP =...

Two 2D Metal–Organic Frameworks Based on Purine Carboxylic Acid Ligands for Photocatalytic Oxidation of Sulfides and CO2 Chemical Fixation

“…Adsorption experiments showed that the maximum adsorption capacity of CO 2 was 22.23 cm 3 /g (1 atm) at 273 K (Figure S60), indicating that Er-MOF had an affinity for CO 2 and contributed to the occurrence of the CO 2 cycloaddition reaction. In addition, the synergistic effects of Lewis acid and base sites were critical for the cycloaddition reaction of epoxides and CO 2 , so a plausible catalytic reaction mechanism was proposed. − First, the Lewis acid site (Er center) polarizes the epoxide through the coordination interaction, and the activated epoxide is opened by Br – ions of TBAB as nucleophiles to form a metal-coordinated bromoalkoxide intermediate. Meanwhile, the Lewis base site (uncoordinated N atoms in the ligand) activates the CO 2 molecule, which then forms an alkylcarbonate anion with the ring-opened epoxide, and then it is converted to cyclic carbonate by an intramolecular ring-closing reaction, and regenerating the catalyst and cocatalyst can be used in the next cycle (Figure ).…”

A thiol-containing zirconium MOF functionalized with silver nanoparticles for synergistic CO2 cycloaddition reactions

“…64,65 Mainly, synthesis of cyclic carbonates from epoxides has attracted considerable attention because of their applications as fine chemicals in pharmaceutical industries, starting materials in polymer industries, electrolytes in battery industries, etc . 66,67 Over the years, zeolites, 68 porous-organic polymers (POPs), 69 coordination organic frameworks (COFs), 70,71 metal–organic frameworks (MOFs), 72–77 and nanoparticle supported materials 49–53,78 have been utilized for the conversion of epoxides to cyclic carbonates. Still, due to the chemical inertness of CO 2 , the utilized reaction conditions in these catalysts are relatively harsh.…”