Enantioselective Hydrogenation of Olefins Enhanced by Metal-Organic Framework Additives

Robust Homochiral Polycrystalline Metal-Organic Framework Membranes for High-Performance Enantioselective Separation

Homochiral MOF membranes offer a promising route to efficient chiral separation, but their fabrication remains challenging. Here, we report for the first time the design and preparation of homochiral polycrystalline MOF-808 membranes for the first time. The membrane exhibits a high integrity and thin membrane thickness. Achieving homochirality through chiral amino acid postsynthetic modification, MOF-808 membranes demonstrate remarkable solvent stability. Notably, they successfully separated racemic naproxen enantiomers, achieving enantiomeric excess (ee) values of up to ∼95.0%. This work paves the way for turning achiral polycrystalline MOF membranes into high-performance chiral membranes for enantioselective separation.

as a Versatile and Predictable Chiral Stationary Phase for the Resolution of Racemic Mixtures

Metal-organic frameworks (MOFs) have become promising materials for multiple applications due to their controlled dimensionality and tunable properties. The incorporation of chirality into their frameworks opens new strategies for chiral separation, a key technology in the pharmaceutical industry as each enantiomer of a racemic drug must be isolated. Here, we describe the use of a combination of computational modeling and experiments to demonstrate that high-performance liquid chromatography (HPLC) columns packed with TAMOF-1 as the chiral stationary phase are efficient, versatile, robust, and reusable with a wide array of mobile phases (polar and non-polar). As proof of concept, in this article, we report the resolution with TAMOF-1 HPLC columns of nine racemic mixtures with different molecular sizes, geometries, and functional groups. Initial in silico studies allowed us to predict plausible separations in chiral compounds from different families, including terpenes, calcium channel blockers, or P-stereogenic compounds. The experimental data confirmed the validity of the models and the robust performance of TAMOF-1 columns. The added value of in silico screening is an unprecedented achievement in chiral chromatography.

The use of metal-organic frameworks as heterogeneous catalysts

This article presents an overview of some of the available research studies of MOFs as catalysts. Catalytic studies of magnetic iron oxide nanoparticles with modified surfaces, MOFs with precious metals such as palladium, platinum, and silver, with zirconium, hafnium, copper, alkaline earth metals, lanthanides are generalized. The studies of the catalytic activity of micro- and mesoporous MOF structures are described.

Chiral Metal-Organic Frameworks

In the past two decades, metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) assembled from metal ions or clusters and organic linkers via metal-ligand coordination bonds have captivated significant scientific interest on account of their high crystallinity, exceptional porosity, and tunable pore size, high modularity, and diverse functionality. The opportunity to achieve functional porous materials by design with promising properties, unattainable for solid-state materials in general, distinguishes MOFs from other classes of materials, in particular, traditional porous materials such as activated carbon, silica, and zeolites, thereby leading to complementary properties. Scientists have conducted intense research in the production of chiral MOF (CMOF) materials for specific applications including but not limited to chiral recognition, separation, and catalysis since the discovery of the first functional CMOF (i.e., d- or l-POST-1). At present, CMOFs have become interdisciplinary between chirality chemistry, coordination chemistry, and material chemistry, which involve in many subjects including chemistry, physics, optics, medicine, pharmacology, biology, crystal engineering, environmental science, etc. In this review, we will systematically summarize the recent progress of CMOFs regarding design strategies, synthetic approaches, and cutting-edge applications. In particular, we will highlight the successful implementation of CMOFs in asymmetric catalysis, enantioselective separation, enantioselective recognition, and sensing. We envision that this review will provide readers a good understanding of CMOF chemistry and, more importantly, facilitate research endeavors for the rational design of multifunctional CMOFs and their industrial implementation.

Heterogeneous Metal-Organic Framework Catalysts for Suzuki-Miyaura Cross Coupling in the Pharma Industry

The synthesis of drug substances (DS) requires the continuous effort of the pharma industry to ensure high sustainability standards. The Suzuki-Miyaura cross coupling is a fundamental C-C bond-forming reaction to produce complex DS intermediates. The present contribution points out the way in which the synthesis of DS intermediates by C-C cross coupling can be economically competitive, while minimizing waste by selecting the appropriate heterogeneous catalyst. By comparing homogeneous, immobilized heterogeneous catalysts on silica and metal-organic framework (MOF) catalysts, while considering the perspectives of academia and industry, the critical parameters for a successful industrial application of heterogeneous catalytic Suzuki-Miyaura cross coupling reactions were identified. Heterogeneous catalysts, such as MOFs, may provide a complementary platform for reducing waste and the costs of production related to such transformations.

Green Conversion of CO2 and Propargylamines Triggered by Triply Synergistic Catalytic Effects in Metal-Organic Frameworks

Cyclization of propargylamines with CO₂ to obtain 2-oxazolidone heterocyclic compounds is an essential reaction in industry but it is usually catalyzed by noble-metal catalysts with organic bases as co-catalysts under harsh conditions. We have synthesized a unique Cu^I /Cu^II mixed valence copper-based framework {[(Cu^I ₆ I₅ )Cu₃ ^II L₆ (DMA)₃ ](NO₃ )⋅9DMA}_n (1) with good solvent and thermal stability, as well as a high density of uncoordinated amino groups evenly distributed in the large nanoscopic channels. Catalytic experiments show that 1 can effectively catalyze the reaction of propargylamines with CO₂ , and the yield can reach 99 %. The turnover frequency (TOF) reaches a record value of 230 h^-1 , which is much higher than that of reported noble-metal catalysts. Importantly, this is the first report of heterogeneously catalyzed green conversion of propargylamines with CO₂ without solvents and co-catalysts under low temperature and atmospheric pressure. A mechanistic study reveals that a triply synergistic catalytic effect between Cu^I /Cu^II and uncoordinated amino groups promotes highly efficient and green conversion of CO₂ . Furthermore, 1 directly catalyzes this reaction with high efficiency when using simulated flue gas as a CO₂ source.

Metal-organic frameworks as kinetic modulators for branched selectivity in hydroformylation

Finding heterogeneous catalysts that are superior to homogeneous ones for selective catalytic transformations is a major challenge in catalysis. Here, we show how micropores in metal-organic frameworks (MOFs) push homogeneous catalytic reactions into kinetic regimes inaccessible under standard conditions. Such property allows branched selectivity up to 90% in the Co-catalysed hydroformylation of olefins without directing groups, not achievable with existing catalysts. This finding has a big potential in the production of aldehydes for the fine chemical industry. Monte Carlo and density functional theory simulations combined with kinetic models show that the micropores of MOFs with UMCM-1 and MOF-74 topologies increase the olefins density beyond neat conditions while partially preventing the adsorption of syngas leading to high branched selectivity. The easy experimental protocol and the chemical and structural flexibility of MOFs will attract the interest of the fine chemical industries towards the design of heterogeneous processes with exceptional selectivity.

The Co-catalysed hydroformylation of olefins produces selectively linear but not branched aldehydes. Here, the authors show that microporous MOFs increase the olefins density in the pores beyond neat conditions allowing high branched selectivity through kinetic modulation when added to a liquid phase hydroformylation mixture.

Homochiral metal–organic frameworks as heterogeneous catalysts

Homochiral metal–organic frameworks (HMOFs) are attractive materials for asymmetric catalysis because they possess high surface area and uniform active sites.