Sustainable Heterogeneous Catalysts for CO₂ Utilization by Using Dual Ligand Zn^II/Cd^II Metal–Organic Frameworks

Abstract

Two-dimensional Zn /Cd -based dual ligand metal-organic frameworks (MOFs) {[M(CHDC)(L)]⋅H O} involving 4-pyridyl carboxaldehyde isonicotinoylhydrazone (L) in combination with flexible 1,4-cyclohexanedicarboxylic acid (H CHDC) as linkers have been synthesized by adaptable synthetic protocols including a green mechanochemical (grinding) method. Characterization, chemical/thermal stability, phase purity, and solid-state luminescent properties of both MOFs have been established by various analytical methods. Structural analysis revealed dimeric metal clusters composed of [M (CHDC) ] loops doubly pillared with L, generating a 2D framework. Both MOFs can be used as highly active solvent-free binary catalysts for CO cycloaddition with epoxides in the presence of the co-catalyst tetrabutylammonium bromide (TBAB) with good catalytic conversion in up to six catalytic cycles without significant loss of activity. The present investigation demonstrates the application of MOFs as efficient heterogeneous catalysts for CO utilization under moderate reaction conditions. Based on the single-crystal X-ray data, a probable mechanism for the cycloaddition reaction has also been proposed.

Design of Engineered Cyclodextrin Derivatives for Spontaneous Coating of Highly Porous Metal-Organic Framework Nanoparticles in Aqueous Media

“…Metal-organic frameworks (MOFs) are currently among the most versatile materials, with crystalline porous structures built using organic linkers and metal cations. Since they were discovered [1], their applications were focused on biosensing, gas storage, separation, heterogeneous catalysis, and imaging [2,3,4,5,6,7,8]. More recently, their innovative biomedical applications as potential drug delivery nanocarriers are gaining increasing interest for the treatment of a variety of diseases [9,10,11,12].…”

Synthesis of Metal Organic Frameworks by Ball-Milling

“…For example, PXRD patterns of products obtained by water slurry (WS) and mechanochemical (BM and twin screw extrusion, TSE) are different from the same starting materials of Co(NO 3 ) 2 •6H 2 O and BPY [80] (Figure 10). Moreover, the ball milling method can introduce more defects into MOFs (Figure 11) [82,83], which makes their specific surface area larger and pore structure richer, which is conducive to its application in adsorption [23] and catalysis [44]. Li et al [23] demonstrated that HKUST-1 synthesized by mechanochemical method has a larger specific surface area and higher pore volume than HKUST-1 synthesized by hydrothermal method, and it has a medium-micro and double-pored structure, in which the micropores are conducive to the strong adsorption of adsorbate molecules, and the porous mesopores are conducive to the adsorption and diffusion of adsorbate molecules.…”

Guanidyl-implanted UiO-66 as an efficient catalyst for the enhanced conversion of carbon dioxide into cyclic carbonates

“…Metal–organic frameworks (MOFs) are recognized as a promising platform for transforming carbon dioxide, 12–14 with fascinating features such as large surface areas, tailorable porosities, tunable configurations, and abundant metal active sites. 15 Metal clusters with coordinatively unsaturated sites (CUS) in MOF nodes generally serve as Lewis acidic sites for catalytic reactions.…”