Engineered MOFs and Enzymes for the Synthesis of Active Pharmaceutical Ingredients

Metal-organic frameworks for biomedical applications: A review

Metal-organic frameworks (MOFs) are emergent materials in diverse prospective biomedical uses, owing to their inherent features such as adjustable pore dimension and volume, well-defined active sites, high surface area, and hybrid structures. The multifunctionality and unique chemical and biological characteristics of MOFs allow them as ideal platforms for sensing numerous emergent biomolecules with real-time monitoring towards the point-of-care applications. This review objects to deliver key insights on the topical developments of MOFs for biomedical applications. The rational design, preparation of stable MOF architectures, chemical and biological properties, biocompatibility, enzyme-mimicking materials, fabrication of biosensor platforms, and the exploration in diagnostic and therapeutic systems are compiled. The state-of-the-art, major challenges, and the imminent perspectives to improve the progressions convoluted outside the proof-of-concept, especially for biosensor platforms, imaging, and photodynamic therapy in biomedical research are also described. The present review may excite the interdisciplinary studies at the juncture of MOFs and biomedicine.

Tuning Ni-Pyrazolate Frameworks by Post-Synthetic Fe-Incorporation for Oxidase-Mimicking H2 O2 Activation

The introduction of iron ionic sites by metal exchange of defective homometallic nickel pyrazolate frameworks generates non-precious, Earth-abundant, first-row heterometallic Fe/Ni-pyrazolate frameworks. The Fe incorporation at the Ni nodes of the framework allows to control the hydrogen peroxide activation, minimizing its decomposition and O2 liberation, occurring at the homometallic Ni nodes. The generation of Fe-OH reactive oxygen species at the heterometallic Fe/Ni nodes is demonstrated by the higher activity in the proof-of-concept oxidation of 1-phenylethanol to acetophenone in an aqueous medium.

MOF-supported crystalline ionic liquid: new type of solid electrolyte for enhanced and high ionic conductivity

Solid-state electrolyte (SSE) is crucial for a high-performance all-solid-state battery. Here, a new solid sodium electrolyte based on the ionic liquid EIMS-NaTFSI and one metal-organic framework (MOF) UiO-67-MIMS functionalized with zwitterion groups MIMS was obtained (UiO-67 and was assembled with 4,4'-biphenyldicarboxylate linker and cluster Zr₆O₄(OH)₄) (EIMS = 1-(1-ethyl-3-imidazolio)propane-3-sulfonate, NaTFSI = sodium bis(trifluoromethanesulfonyl)imide, MIMS = 1-(1-mthyl-3-imidazolio)propane-3-sulfonate). By contacting and pairing EIMS-NaTFSI (abbreviated as EN-1) to the MIMS group on the framework, EN-1 was directed and arranged along the channels within UiO-67-MIMS, forming a solid composite EN-1@UiO-67-MIMS with Bragg scatter, i.e., a crystalline ionic liquid containing Na⁺ salts (NaTFSI). Such an ionic liquid EN-1@UiO-67-MIMS bearing crystalline MOF matrix showed and preserved fast ion conduction (1.02 × 10^-2 S cm^-1) at 150 °C even after 30 days, and exhibited 1-2 orders of magnitude higher conductivities than the bulk ionic liquid EN-1 within a wide temperature range, although the ion content in the latter was higher. The infinite pathway paved by the EN-1 arranged and contacted the MIMS along the channels within MOF well accounts for the fast ion transmission and the stability of the solid-state electrolyte. Such MOF-based crystalline ionic liquid provides a new strategy for developing high-performance solid-state electrolytes for ions.

Microfluidic fabrication of hydrogel microparticles with MOF-armoured multi-enzymes for cascade biocatalytic reactions

Uniform hydrogel microparticles with ZIF-8 nanoparticles for molecular co-confinement of cascade enzymes are developed by microfluidics to achieve enhanced stability and reusability under harsh conditions.

Controlling the molecular diffusion in MOFs with the acidity of monocarboxylate modulators

The catalytic performance of metal-organic frameworks (MOFs) is related to their physicochemical properties, such as particle size, defect chemistry and porosity, which can be potentially controlled by coordination modulation. By combining PXRD, ¹HNMR, FT-IR, and N₂ uptake measurements we have gained insights into the control of different types of defects (missing linker or missing cluster consequence of the spatial distribution of missing linkers, and a combination of both) by the type of modulator employed. We show that the molar percent of defects, either as missing linkers or as a part of missing cluster defects, is related to the acidity of a modulator and its subsequent incorporation into the UiO-66 structure. Modulators with strong acidity and small size result in a considerable defect induction that causes an increase in the external surface area and mesopore volume, which is beneficial for the ring-opening of epoxides with amines, using UiO-66 defect-modulated MOFs as heterogeneous catalysts.

Synthesis and practical applications of 2-(2-nitroalkyl)pyrroles

Functionalization of pyrroles introducing a 2-nitroalkyl moiety allows the formation of nitro-containing compounds to be used as pivotal intermediates for the synthesis of bioactive compounds. The reaction of pyrroles with nitroalkenes under the Friedel-Crafts conditions allows a direct entry to 2-(2-nitroalkyl)pyrroles. This approach can also be used for the preparation of enantioenriched derivatives exploiting asymmetric catalysis. In a complementary fashion, the Henry reaction between 2-formylpyrroles and nitroalkanes generates the corresponding nitroaldol products which upon dehydration and reduction of the intermediate 2-pyrrolylnitroethene efficiently afford 2-(2-nitroalkyl)pyrroles. This review article summarizes the most relevant procedures for the preparation of 2-(2-nitroalkyl)pyrroles during the last two decades as well as their significant practical applications.

Metal-Organic Frameworks as Versatile Heterogeneous Solid Catalysts for Henry Reactions

Metal–organic frameworks (MOFs) have become one of the versatile solid materials used for a wide range of applications, such as gas storage, gas separation, proton conductivity, sensors and catalysis. Among these fields, one of the more well-studied areas is the use of MOFs as heterogeneous catalysts for a broad range of organic reactions. In the present review, the employment of MOFs as solid catalysts for the Henry reaction is discussed, and the available literature data from the last decade are grouped. The review is organized with a brief introduction of the importance of Henry reactions and structural properties of MOFs that are suitable for catalysis. The second part of the review discusses the use of MOFs as solid catalysts for the Henry reaction involving metal nodes as active sites, while the third section provides data utilizing basic sites (primary amine, secondary amine, amides and urea-donating sites). While commenting on the catalytic results in these two sections, the advantage of MOFs over other solid catalysts is compared in terms of activity by providing turnover number (TON) values and the structural stability of MOFs during the course of the reaction. The final section provides our views on further directions in this field.

Catalytic activity of a CuGHK peptide-based porous material

The CuGHK peptide-based porous material acts as a heterogeneous organocatalyst in the Henry reaction due to a periodic distribution of pockets decorated with lysine side chain active sites.

Unexpected linker-dependent Brønsted acidity in the (Zr)UiO-66 metal organic framework and application to biomass valorization

The functionality of the UiO-66(Zr) linkers affects the number of defects on the Zr6 clusters, leading to differences in the MOFs' Brønsted acidity, which promotes the dehydration of fructose into HMF.

Cooperative acid–base bifunctional ordered porous solids in sequential multi-step reactions: MOF vs. mesoporous silica

Two different catalytic platforms, MOF and mesoporous silica, were compared as porous support for basic amino groups to promote sequential multi-step reactions.

Organic synthesis of high added value molecules with MOF catalysts

Recent examples of organic synthesis of fine chemicals and pharmaceuticals in confined spaces of MOFs are highlighted and compared with silica-based ordered porous solids, such as zeolites or mesoporous (organo)silica. These heterogeneous catalysts offer the possibility of stabilizing the desired transition states and/or intermediates during organic transformations of functional groups and (C-C/C-N) bond forming steps towards the desired functional high added value molecular scaffolds. A short introduction on zeolites, mesoporous silica and metal-organic frameworks is followed by relevant applications in which confined active sites in the pores promote single or multi-step organic synthesis of industrially relevant molecules. A critical discussion on the catalytic performances of the different types of hybrid inorganic-organic catalysts in the synthesis of O- and N-containing acyclic and heterocyclic molecules has been presented.

Fluorescent biosensor based on magnetic cross-linking enzyme aggregates/CdTe quantum dots for the detection of H2O2-bioprecursors

A fluorescent sensing system for H₂O₂-bioprecursors based on CdTe quantum dots and magnetic cross-linking enzyme aggregates was designed.

Layered Double Hydroxides: A Toolbox for Chemistry and Biology

Layered double hydroxides (LDHs) are an emergent class of biocompatible inorganic lamellar nanomaterials that have attracted significant research interest owing to their high surface-to-volume ratio, the capability to accumulate specific molecules, and the timely release to targets. Their unique properties have been employed for applications in organic catalysis, photocatalysis, sensors, drug delivery, and cell biology. Given the widespread contemporary interest in these topics, time-to-time it urges to review the recent progresses. This review aims to summarize the most recent cutting-edge reports appearing in the last years. It firstly focuses on the application of LDHs as catalysts in relevant chemical reactions and as photocatalysts for organic molecule degradation, water splitting reaction, CO2 conversion, and reduction. Subsequently, the emerging role of these materials in biological applications is discussed, specifically focusing on their use as biosensors, DNA, RNA, and drug delivery, finally elucidating their suitability as contrast agents and for cellular differentiation. Concluding remarks and future prospects deal with future applications of LDHs, encouraging researches in better understanding the fundamental mechanisms involved in catalytic and photocatalytic processes, and the molecular pathways that are activated by the interaction of LDHs with cells in terms of both uptake mechanisms and nanotoxicology effects.