Multifunctional Biomass-Based Ionic Liquids/CuCl-Catalyzed CO2-Promoted Hydration of Propargylic Alcohols: A Green Synthesis of α-Hydroxy Ketones

α-Hydroxy ketones are a class of vital organic skeletons that generally exist in a variety of natural products and high-value chemicals. However, the traditional synthetic route for their production involves toxic Hg salts and corrosive H2SO4 as catalysts, resulting in harsh conditions and the undesired side reaction of Meyer-Schuster rearrangement. In this study, CO2-promoted hydration of propargylic alcohols was achieved for the synthesis of various α-hydroxy ketones. Notably, this process was catalyzed using an environmentally friendly and cost-effective biomass-based ionic liquids/CuCl system, which effectively eliminated the side reaction. The ionic liquids utilized in this system are derived from natural biomass materials, which exhibited recyclability and catalytic activity under 1 bar of CO2 pressure without volatile organic solvents or additives. Evaluation of the green metrics revealed the superiority of this CuCl/ionic liquid system in terms of environmental sustainability. Further mechanistic investigation attributed the excellent performance to the ionic liquid component, which exhibited multifunctionality in activating substrates, CO2 and the Cu component.

Correlating Single-Atomic Ruthenium Interdistance with Long-Range Interaction Boosts Hydrogen Evolution Reaction Kinetics

Correlated single-atom catalysts (c-SACs) with tailored intersite metal-metal interactions are superior to conventional catalysts with isolated metal sites. However, precise quantification of the single-atomic interdistance (SAD) in c-SACs is not yet achieved, which is essential for a crucial understanding and remarkable improvement of the correlated metal-site-governed catalytic reaction kinetics. Here, three Ru c-SACs are fabricated with precise SAD using a planar organometallic molecular design and π-π molecule-carbon nanotube confinement. This strategy results in graded SAD from 2.4 to 9.3 Å in the Ru c-SACs, wherein tailoring the Ru SAD into 7.0 Å generates an exceptionally high turnover frequency of 17.92 H2 s-1 and a remarkable mass activity of 100.4 A mg-1 under 50 and 100 mV overpotentials, respectively, which is superior to all the Ru-based catalysts reported previously. Furthermore, density functional theory calculations confirm that Ru SAD has a negative correlation with its d-band center owing to the long-range interactions induced by distinct local atomic geometries, resulting in an appropriate electrostatic potential and the highest catalytic activity on c-SACs with 7.0 Å Ru SAD. The present study promises an attractive methodology for experimentally quantifying the metal SAD to provide valuable insights into the catalytic mechanism of c-SACs.

Recent Progress on the Synthesis and Modified Strategies of Zeolitic-Imidazole Framework-67 Towards Electrocatalytic Oxygen Evolution Reaction

As a class of metal-organic framework, the zeolitic-imidazole framework-67 is constructed from bridging cobalt ions and 2-methylimidazole. The high content of abundant active cobalt species, uniform structure, ultrahigh porosity, and large surface area show the potential for multiple catalytic applications, especially electrocatalytic oxygen evolution reaction (OER). The design and synthetic strategies of catalyst-based ZIF-67 that approach the maximized catalytic performance are still challenging in further development. Herein, the current progress strategy on the structural design, synthetic route, and functionalization of electrocatalysts based on ZIF-67 to boost the catalytic performance of OER is reviewed. Besides, the structurally designed catalyst from various fabricated strategies corresponding to enhancing catalytic activity is discussed. The emphasized review for understanding design and synthetic structure with catalytic performance could guide researchers in further developing catalyst-based ZIF-67 for improving the efficient electrocatalytic OER.

Single-thermal synthesis of bimetallic Co/Zn@NC under solvent-free conditions as an efficient dual-functional oxygen electrocatalyst in Zn-air batteries

A straightforward in situ thermal (IST) method is developed to synthesize bimetallic Co/Zn embedded in nitrogen-doped three-dimensional carbon (CoZn@NC_IST). The facile IST process is a single-step thermal treatment of a mixture of metals (Co/Zn) and 2-methylimidazole precursors under solvent-free conditions. This straightforward method is advantageous over the traditional synthesis derived from CoZn-ZIF (CoZn@NC_Solv). During the IST method, the bimetallic Co/Zn bridged with 2-methylimidazole forming zeolitic-imidazole frameworks (ZIFs) under low-temperature (<200 °C) conditions before being de-coordinated and sacrificed their structure into a carbon material at high temperature (>500 °C). Loading zinc into the mixture of precursors contributed to the metal distribution and increased the surface area compared with the sample without zinc (Co@NC_IST). CoZn@NC_IST exhibits a bifunctional electrocatalytic ability for the ORR (0.855 V@E_1/2) and OER (overpotential of 325 mV@10 mA cm^-2). Applying CoZn@NC_IST in a zinc-air battery confirmed its excellent and effective dual-function electrocatalytic performance. Herein, using the advanced single-step method of IST in the absence of any solvent, we provide a powerful and green synthesis of an electrocatalyst that is a potential candidate for industrial applications.

Strategies for induced defects in metal-organic frameworks for enhancing adsorption and catalytic performance

Metal-organic frameworks (MOFs) have emerged among porous materials. The designable structure and specific functionality make them stand out for diverse applications. In conceptual MOF, the metal ions/clusters and organic ligands...

Simultaneous transformation of 2D to 3D and doped metal transitions of zeolitic imidazole frameworks under solid phase and free-solvent conditions

The post-thermal treatment (PTT) method was applied for crystal transformation on the structure of zeolitic imidazolate frameworks (ZIFs) from 2D to 3D under solvent-free conditions. The investigation was performed based on bridging of the cobalt ions by the 2-methylimidazole linker to form the ZIF structure. Extensive characterization revealed that the reaction mechanism was a transformation in the solid crystal phase and resulted from the de-coordination of the framework and reformation of the crystalline structure. In addition, the PTT method opens the opportunity to simultaneously dope transition metals (Zn, Co, Fe, Ni, and Mn) in the framework during the transformation of ZIFs. The materials with doped metals showed enhanced properties and excellent performance for applications including gas adsorption, dye degradation, and the catalytic activity of CO₂ fixation.

Sacrificial ZnO nanorods drive N and O dual-doped carbon towards trifunctional electrocatalysts for Zn–air batteries and self-powered water splitting devices

Integrated energy systems (IES) have attracted increasing attention in recent years.

Cross-Linked Mixed-Matrix Membranes Using Functionalized UiO-66-NH2 into PEG/PPG-PDMS-Based Rubbery Polymer for Efficient CO2 Separation

Mixed-matrix membranes (MMMs) with an ideal polymer-filler interface and high gas separation performance are very challenging to fabricate because of incompatibility between the fillers and the polymer matrix. This work provides a simple technique to prepare a series of cross-linked MMMs (xMMM@n) by covalently attaching UiO-66-NB metal-organic frameworks (MOFs) within the PEG/PPG-PDMS copolymer matrix via ring-opening metathesis polymerization and in situ membrane casting. The norbornene-modified MOF (UiO-66-NB) is successfully copolymerized and dispersed homogeneously into a PEG/PPG-PDMS matrix because of very fast polymer formation and strong covalent interaction between MOFs and the rubbery polymer. A significant improvement in gas permeability is achieved in membranes up to a 5 wt % MOF loading compared to the pristine polymer membrane without affecting selectivity. The CO₂/N₂ separation performance of xMMM@1, xMMM@3, and xMMM@5 with 1, 3, and 5 wt % MOF loading, respectively, surpassed Robeson's 2008 upper bound. In addition, the best performing membrane, xMMM@3 (P_CO2 = 585 Barrer and CO₂/N₂ ∼53), approaches the 2019 upper bound, indicating that the cross-linked MMMs (xMMM@n) are very promising for CO₂ separation from flue gas. The experimental results of our study were evaluated and are supported by theoretical data obtained using the Maxwell model for MMMs. Moreover, the developed MMMs, xMMM@ns, displayed outstanding antiplasticization performance at pressures of up to 25 atm and very stable antiaging performance for up to 11 months with good temperature switching behaviors.

Kinetic modeling of heterogeneous esterification reaction using initial reaction rate analysis: data extraction and evaluation of mass transfer criteria

This data article provides detailed guidance to obtain heterogeneous reaction rate expressions and the corresponding initial reaction rates and their application. Explanation is provided to deal with specific criteria to rule out internal and external concentration gradients, so that the usage of intrinsic catalytic data is guaranteed. Overall, the main goal is to provide an easy tool to evaluate both aforementioned results by simple plug-and-play of available reaction data.

Value of the Data

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The presented data and corresponding data treatment can be put forward by other researchers in order to guarantee the acquisition of intrinsic experimental data for catalytic reactions.

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The presented data can be used as an example to set up typical heterogeneous esterification reactions by researchers working on catalytic systems with the specific purpose of kinetic modeling.

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Data treatment in order to calculate initial reaction rates is explained in detail with example. This has a high applicability and very easy practicability for users in the research field of heterogeneous catalysis.

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Concentration gradients, which might destroy the intrinsic character of the experimental data, can be ruled out via simple criteria. How to use the data is explained in this manuscript.

Thermochemical transformation in the single-step synthesis of zeolitic imidazole frameworks under solvent-free conditions

An environmentally friendly and economical route for the synthesis of zeolitic imidazole frameworks (ZIFs) was developed based on the thermal treatment of mixed solid precursors in the absence of solvent and additive compounds. This facile, rapid, and one-step synthetic method involves the heat treatment of a mixture of solid precursors (metal and linker). The solid mixture was transformed into a porous crystalline material without post-treatment and in the absence of any solvent. The synthesized materials are nanocrystals (200-500 nm) with sodalite topology, similar to conventionally prepared ZIFs. The properties of the synthesized materials were evaluated using powder X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, porosity and surface area analysis, gas adsorption, and thermal gravimetric analysis. The metal-oxide precursor, which is typically considered to be inert in the context of chemical synthesis, was readily transformed into a ZIF using this thermochemical method. The developed solvent-free, fast, and eco-friendly synthetic method for the preparation of porous ZIFs may be applicable for large-scale industrial synthesis.

Author Correction: Chemical fixation of carbon dioxide catalyzed via cobalt (III) ONO pincer ligated complexes

In the original version of this Article, the affiliation for Hussein A. Younus with “Chemistry Department, Faculty of Science, Fayoum University, Fayoum 63514, Egypt” was omitted. This has now been corrected in both the PDF and HTML versions of the Article.

CO2 insertion into epoxides using cesium salts as catalysts at ambient pressure

Cesium salts (Cs₂CO₃, CsCl, and CsNO₃) were used for the coupling of CO₂ and epoxides.

Data for the synthesis of β-oxopropylcarbamates from propargylic alcohols, secondary amines and CO2 catalyzed by a recyclable AgBr/ionic liquid system under ambient pressure

Data presented here are related with the research article entitled "Synthesis of ß -oxopropylcarbamates in a recyclable AgBr/ionic liquid catalytic system: An efficient assembly of CO2 under ambient pressure" (Song et al., 2018) [1]. In this data article, the general synthetic procedures of ß-oxopropylcarbamates through the three-component reaction of propargylic alcohols, secondary amines and carbon dioxide (CO2) catalyzed by a recyclable AgBr/ionic liquid (IL) system under mild pressure are described. Furthermore, the process for recycling the catalysts is supplied as well. Specifically, the investigative data for the temperature, amount of ILs, reaction time as well as the state of silver in the system are also reported. Finally, all the target products are confirmed by 1H NMR, 13C NMR, and high-resolution mass spectroscopy (HR-MS).

MoO3NPs/ZIF-8 composite material prepared via RCVD for photodegradation of dyes

Toxic wastewaters from the textile industry have made its way into rivers and other waterways, posing a serious health treat on both human and wildlife. Herein, this data set presents the potential use of MoO₃ nanoparticles supported on ZIF-8 in the photodegradation of a cationic dye molecule. The data presented in this article report a concise description of experimental conditions for the spray-dried ZIF-8 synthesis and subsequent deposition of MoO₃ nanoparticles via rotary chemical vapor deposition (RCVD). The photodegradation and analysis data reviled that the MoO₃-NPs@ZIF-8 3 wt% displayed the ability of degrading methylene blue up to 82% and 95% after 180 and 300 min, respectively.

METAL-ORGANIC FRAMEWORKS APPLIED FOR WATER PURIFICATION

Metal-organic frameworks (MOFs) which are materials constructed from metal ions/clusters bridged with organic linkers have emerged as an important family of porous materials for widely varying applications. The purification of water polluted with both of organic and inorganic contaminants is a potentially promising application of MOFs since the chemical and thermal properties of the porous materials are easily tunable, e.g. ligand modification, different metal, etc. The demonstration of alignment and the obtained insights facilitate the direction of designing ideal MOF materials with improved water stability for application in water purification. This review gives a brief overview and will be beneficial to the design, functionalization, and promotion of the development of MOFs as adsorbent materials for applications in water purification.

Post-synthetically modified MOF for the A3-coupling reaction of aldehyde, amine, and alkyne

A new heterogeneous NHC catalyst (Ag-NHC-MOF) was synthesized by the post-synthetic modification of an azolium-containing metal–organic framework.

Synthesis and characterization of [Ru(NCNHCO)(bpy)L]+ complexes and their reactivity towards water oxidation

The role of charged axial ligands in tuning the reactivity and stability of Ru WOCs is well-known, less is explored when axial ligands are neutral molecules.

Spray drying of zeolitic imidazolate frameworks: investigation of crystal formation and properties

The mechanism of crystal growth for ZIFs (ZIF-67 and Zn/Co-ZIF) is explored for the first time using the spray-drying technique.

Ring-Opening Polymerization of l-Lactide to Cyclic Poly(Lactide) by Zeolitic Imidazole Framework ZIF-8 Catalyst

The catalytic activity of ZIF-8 in the ring-opening polymerization of l-lactide without solvents or cocatalysts is presented for the first time. Two different synthetic strategies have been applied for synthesizing ZIF-8, either under solvothermal condition or by spray-drying procedure. Their catalytic activities are found to be correlating with the presence of open active sites in ZIF-8 structure. The structural defects that afford active acid and basic sites are supposed to cooperatively catalyze the reaction. ZIF-8 assembled by spray-drying technique, displays a superior catalytic activity at temperature of 160 °C, leading to the formation of high molecular weight cyclic polylactide. The ZIF-8 catalysts could be recycled and reused without any significant loss of catalytic activity.

CO2 Cycloaddition to Epoxides by using M-DABCO Metal-Organic Frameworks and the Influence of the Synthetic Method on Catalytic Reactivity

A series of high‐quality M₂(BDC)₂(DABCO) metal–organic frameworks (abbreviated as M‐DABCO; M=Zn, Co, Ni, Cu; BDC=1,4‐benzene dicarboxylate; DABCO=1,4‐diazabicyclo[2.2.2]octane), were synthesized by using a solvothermal (SV) method, and their catalytic activity for the cycloaddition of CO₂ to epoxides in the absence of a co‐catalyst or solvent was demonstrated. Of these metal–organic frameworks (MOFs), Zn‐DABCO exhibited very high activity and nearly complete selectivity under moderate reaction conditions. The other members of this MOF series (Co‐DABCO, Ni‐DABCO, and Cu‐DABCO) displayed lower activity in the given sequence. Samples of Zn‐DABCO, Co‐DABCO, and Ni‐DABCO were recycled at least three times without a noticeable loss in catalytic activity. The reaction mechanism can be attributed to structural defects along with the acid–base bifunctional characteristics of these MOFs. Moreover, we illustrate that the synthetic method of M‐DABCO influences the yield of the reaction. In addition to the SV method, Zn‐DABCO was synthesized by using spray drying due to its industrial attractiveness. It was found that the synthesis procedure clearly influenced the crystal growth and thus the physicochemical properties, such as surface area, pore volume, and gas adsorption, which in turn affected the catalytic performance. The results clarified that although different synthetic methods can produce isostructural MOFs, the application of MOFs, especially as catalysts, strongly depends on the crystal morphology and textural properties and, therefore, on the synthesis method.

A simple and robust AgI/KOAc catalytic system for the carboxylative assembly of propargyl alcohols and carbon dioxide at atmospheric pressure

A simple, robust and economical AgI/KOAc system was developed for the carboxylative assembly of propargyl alcohols and CO₂ under mild conditions applying an unprecedentedly low level of 0.05 mol% Ag loading.

Zeolitic imidazole framework-67 as an efficient heterogeneous catalyst for the conversion of CO2 to cyclic carbonates

ZIF-67 acts as a very efficient catalyst for the cycloaddition of CO₂ to epoxides affording cyclic carbonates with high selectivity, without any need for a solvent or a co-catalyst.