Porous aluminum-based DUT metal-organic frameworks for the transformation of CO2 into cyclic carbonates: A computationally supported study

Nanocomposites Based on Magnetic Nanoparticles and Metal-Organic Frameworks for Therapy, Diagnosis, and Theragnostics

In the last two decades, metal-organic frameworks (MOFs) with highly tunable structure and porosity, have emerged as drug nanocarriers in the biomedical field. In particular, nanoscaled MOFs (nanoMOFs) have been widely investigated because of their potential biocompatibility, high drug loadings, and progressive release. To enhance their properties, MOFs have been combined with magnetic nanoparticles (MNPs) to form magnetic nanocomposites (MNP@MOF) with additional functionalities. Due to the magnetic properties of the MNPs, their presence in the nanosystems enables potential combinatorial magnetic targeted therapy and diagnosis. In this Review, we analyze the four main synthetic strategies currently employed for the fabrication of MNP@MOF nanocomposites, namely, mixing, in situ formation of MNPs in presynthesized MOF, in situ formation of MOFs in the presence of MNPs, and layer-by-layer methods. Additionally, we discuss the current progress in bioapplications, focusing on drug delivery systems (DDSs), magnetic resonance imaging (MRI), magnetic hyperthermia (MHT), and theragnostic systems. Overall, we provide a comprehensive overview of the recent advances in the development and bioapplications of MNP@MOF nanocomposites, highlighting their potential for future biomedical applications with a critical analysis of the challenges and limitations of these nanocomposites in terms of their synthesis, characterization, biocompatibility, and applicability.

Covalent-Frameworked 2D Crown Ether with Chemical Multifunctionality

Here, we present the synthesis and characterization of a novel 2D crystalline framework, named C2O, which mainly consists of carbon and oxygen in a 2:1 molar ratio and features crown ether holes in its skeletal structure. The covalent-frameworked 2D crown ether can be synthesized on a gram-scale and exhibits fine chemical stability in various environments, including acid, base, and different organic solvents. The C2O efficiently activates KI through the strong coordination of K+ with crown ether holes in a rigid framework, which enhances the nucleophilicity of I- and significantly improves its catalytic activity for CO2 fixation with epoxides. The presence of C2O with KI results in remarkable increases in CO2 conversion from 5.7% to 99.9% and from 2.9% to 74.2% for epichlorohydrin and allyl glycidyl ether, respectively. Moreover, C2O possesses both electrophilic and nucleophilic sites at the edge of its framework, allowing for the customization of physicochemical properties by a diverse range of chemical modifications. Specifically, incorporating allyl glycidyl ether (AGE) as an electrophile or ethoxyethylamine (EEA) as a nucleophile into C2O enables the synthesis of C2O-AGE or C2O-EEA, respectively. These modified frameworks exhibit improved conversions of 97.2% and 99.9% for CO2 fixation with allyl glycidyl ether, outperforming unmodified C2O showing a conversion of 74.2%. This newly developed scalable, durable, and customizable covalent framework holds tremendous potential for the design and preparation of outstanding materials with versatile functionalities, rendering them highly attractive for a wide range of applications.

Application of DUT-4 MOF structure switching for optical and electrical humidity sensing

The threshold structural transformation of the DUT-4 metal-organic framework (MOF) from an ordered to distorted phase during exposure to ambient conditions has been revealed. The in situ X-ray diffraction analysis, in situ Raman and FTIR spectroscopy, scanning electron microscopy and synchronous thermal analysis have been used for investigation. The reversible effect of exposure time and humidity on such a phase transition has been confirmed. We also demonstrated that the observed phase transition correlated well with changes in the optical and electronic properties of DUT-4, paving the way to a new family of MOF-based phase change materials for optoelectronic applications.

Cordierite@MOFs with Easy Recovery in CO2 Cycloaddition

The objective of this research is to create monolithic heterogeneous catalysts (cordierite@MOFs) through the application of metal-organic framework (MOF) materials onto honeycomb cordierite for CO2 cycloaddition. By employing monolithic catalysts instead of powdered catalysts, the recycling and reusability of catalysts during postreaction treatment can be significantly improved.

Insight into the Varying Reactivity of Different Catalysts for CO2 Cycloaddition into Styrene Oxide: An Experimental and DFT Study

The cycloaddition of CO₂ into epoxides to form cyclic carbonates is a highly sought-after reaction for its potential to both reduce and use CO₂, which is a greenhouse gas. In this paper, we present experimental and theoretical studies and a mechanistic approach for three catalytic systems. First, as Lewis base catalysts, imidazole and its derivatives, then as a Lewis acid catalyst, ZnI₂ alone, and after that, the combined system of ZnI₂ and imidazole. In the former, we aimed to discover the reasons for the varied reactivities of five Lewis base catalysts. Furthermore, we succeeded in reproducing the experimental results and trends using DFT. To add, we emphasized the importance of non-covalent interactions and their role in reactivity. In our case, the presence of a hydrogen bond was a key factor in decreasing the reactivity of some catalysts, thus leading to lower conversion rates. Finally, mechanistically understanding this 100% atom economy reaction can aid experimental chemists in designing better and more efficient catalytic systems.

Zn(II)-Functionalized COF as a Recyclable Catalyst for the Sustainable Synthesis of Cyclic Carbonates and Cyclic Carbamates from Atmospheric CO2

A simple covalent organic framework (COF) bearing β-ketoenamine units as a potential heterogeneous ligand for ZnII-catalyzed fixation and transformation of CO2 into value-added chemicals is reported. Catalytic investigations convincingly demonstrated...