Catalytic Applications Research Articles

Synthesis of Porphyrin Derivatives Bearing Six Carboxylic Acids for the Formation of Three-Dimensional Hydrogen-Bonded Network Structures.

we synthesized a series of porphyrin derivatives with six carboxylic acid groups to explore their potential in forming hydrogen-bonded networks (YSHs). By systematically varying the position and structure of these carboxylic acid groups, we observed distinct types of hydrogen-bonded frameworks, including two- and three-dimensional networks. Using single-crystal X-ray crystallography, we confirmed that these derivatives form YSHs with unique structural properties influenced by carboxylic acid positioning and π-π interactions. The 1Zn derivative forms a robust 3D hydrogen-bonded network stabilized by π-π stacking interactions, while the 2Ni derivative, with no such stacking, exhibits reduced stability and collapses upon solvent removal. Structural variations like the terphenylene and biphenyl linkers in 3Zn and 4Zn lead to flexible frameworks, while the 5Zn dimer forms two distinct structures depending on the solvent environment. Our findings reveal that careful control over carboxylic acid orientation and linker structure enables the design of diverse hydrogen-bonded networks with tunable stability and dimensionality. These insights advance our understanding of supramolecular assembly principles in porphyrin-based materials and offer new pathways for developing high-performance frameworks for applications in catalysis, sensing, and materials science.

Synthesis of Multishelled Silica Particles by Using Choline Hydroxide as Catalyst.

We present a facile one-pot strategy for synthesizing multishelled silica particles with precisely controlled structural parameters by using choline hydroxide (ChOH) as catalyst. As an efficient organic base catalyst, ChOH effectively regulates the hydrolysis and condensation kinetics of tetraethyl orthosilicate (TEOS), enabling precise control over the silica network condensation degree. Through systematic manipulation of the ChOH addition sequence and ChOH concentration, the shell multiplicity correlates directly with the ChOH addition sequence, while shell thickness can be fine-tuned by adjusting the ChOH concentration. The subsequent hot water etching process selectively removes lower condensation degrees regions of silica particles, yielding well-defined multishelled architectures. This synthetic approach demonstrates versatility in engineering silica particle structures, from simple monoshelled to complex multishelled architectures, providing new opportunities for designing advanced silica-based materials with potential applications in catalysis, molecular sensing, and drug delivery systems.

Elementally Doped Carbonized Polymer Dots: Control of Optical Properties and Their Versatile Applications

AbstractCarbonized polymer dots (CPDs) are a class of luminescent nanomaterials formed through cross‐linking and polymerization. Owing to their excellent biocompatibility, ease of synthesis, good aqueous dispersion, high chemical stability, unique cross‐linking structure, and modifiable surface properties, CPDs have attracted significant attention. However, pure CPDs exhibit certain limitations in terms of optical performance, particularly in terms of fluorescence intensity, phosphorescence intensity, and emission wavelength tunability, which may not meet the requirements of specific applications. To address these limitations, doping CPDs with various elements, such as nitrogen (N), sulfur (S), and phosphorus (P) to modify their band structure and surface functionalization can significantly enhance their optical properties and photochemical stability, thereby expanding their application potential. This paper reviews the main synthesis methods for elementally doped CPDs, examines the effects of different types of elemental doping on their photochemical properties, and explores promising applications in optoelectronic devices, sensors, and catalysis. Finally, recent advancements in elementally doped CPDs are summarized, along with future development directions and challenges.

Tetrafluororesorcin[4]arene Hexameric Capsule Enables the Expansion of the Reactivity Space in Supramolecular Catalysis.

This study presents the development and catalytic applications of the tetrafluororesorcin[4]arene hexameric capsule (capsule II) as a novel supramolecular catalyst. It demonstrates unprecedented catalytic activity, enabling the β-selective glycosylation of glycals to 2-deoxy glycosides─a transformation that has not been achieved before in molecular and supramolecular catalysis. Mechanistic investigations, including experimental and computational studies, revealed that the high β-selectivity arises from a proton wire mechanism along the capsule's surface, coupling glycal protonation with nucleophile deprotonation. Control experiments confirmed the unique reactivity of capsule II compared to its nonfluorinated predecessor, capsule I, showcasing its potential to expand the boundaries of supramolecular catalysis.

Harnessing Multi‐Center‐2‐Electron Bonds for Carbene Metal‐Hydride Nanocluster Catalysis

AbstractN‐Heterocyclic carbene (NHC) ligands possess the ability to stabilize metal‐based nanomaterials for a broad range of applications. With respect to metal‐hydride nanomaterials, however, carbenes are rare, which is surprising if one considers the importance of metal‐hydride bonds across the chemical sciences. In this study, we introduce a bottom‐up approach that leverages preexisting metal‐metal m‐center‐n‐electron (mc‐ne) bonds to access a highly stable cyclic(alkyl)amino carbene (CAAC) copper‐hydride nanocluster, [(CAAC)6Cu14H12][OTf]2 with superior stability compared to Stryker's reagent, a popular commercial phosphine‐based copper hydride catalyst. Density functional theory (DFT) calculations reveal that the enhanced stability stems from hydride‐to‐ligand backbonding with the π‐accepting carbene. This new cluster emerges as an efficient and selective copper‐hydride pre‐catalyst, thereby providing a bench‐stable alternative for catalytic applications.

A Rapid and Surfactant-Free Synthesis Strategy for Variously Faceted Cuprous Oxide Polyhedra

We systematically investigated the morphology-controlled synthesis of Cu2O micro-nano crystals, especially under surfactant-free conditions, targeting a simple, rapid, and morphologically controllable preparation strategy for polyhedral Cu2O micro-nano crystals. By systematically investigating the effects of NaOH concentration, types of reducing agents, and copper salt precursors on crystal growth, precise control over the morphology of Cu2O crystals under surfactant-free conditions was achieved. This method can rapidly prepare variously faceted Cu2O crystals under mild conditions (70 °C, 7 min), including regular polyhedra with low-index facets exposure including cubes, octahedra and rhombic dodecahedra, as well as more complex polyhedra with high-index facets exposure such as 18-faceted, 26-faceted, 50-faceted and 74-faceted crystals. NaOH concentration is found to be the key factor in controlling Cu2O crystal morphology: as the concentration of NaOH increases, the morphology of Cu2O crystals gradually transforms from cubes that fully expose the {100} faces to regular polyhedra that expose the {110}, {111} faces, and even other high-index faces, ultimately presenting octahedra that fully expose the {111} faces. Additionally, Cu2O crystals with unique morphologies such as hollow cubes and 18-faceted with {110} face etched can be obtained by introducing surfactants or prolonging reaction durations. This work provides new insights into the morphology control of Cu2O crystals and establishes foundation in acquiring distinct Cu2O polyhedra in a facile manner for their application in catalysis, optoelectronics, sensing, and energy conversion fields.

Controlled Quantum Well Formation on DNA-Wrapped Carbon Nanotubes via Peroxide-Mediated Aryl Diazonium Reduction.

Quantum well defect-modified single-walled carbon nanotubes are nanomaterials with wide-ranging applications in biosensing, imaging, quantum computing, and catalysis. The most common method for covalent functionalization of nanotubes for biosensing applications involves reactions with aryl diazonium salts to generate sp3 aryl defect sites, commonly followed by wrapping with single-stranded DNA for aqueous dispersion. We describe herein a rapid aryl diazonium functionalization reaction directly compatible with DNA-wrapped nanotubes, mediated by hydrogen peroxide. The reaction uses mild aqueous conditions at physiological pH and can be easily monitored in real-time via fluorescence analysis to control the degree of functionalization. Overall, this reaction greatly simplifies the production of covalently functionalized DNA-wrapped carbon nanotubes, expanding their potential for industrial and biomedical applications.

Multifunctional Thick Films Obtained by Electrodeposition of 1,8-Dihydroxynaphtalene, an Allomelanin Precursor.

The deposition of conformal films from redox-active biological molecules, such as catechols, catecholamines, and other polyphenols, has demonstrated great versatility in terms of the substrate used. Precursors of allomelanins, mainly found in plants and fungi, have been largely overlooked as precursors for the design of conformal and robust coatings. Moreover, their potential application for the electrodeposition of films on conductive substrates has not yet been investigated. Here, the electrodeposition by cyclic voltammetry and chronoamperometry of 1,8-dihydroxynaphthalene (1,8-DHN), a precursor of allomelanin, onto gold electrodes and onto Co-Cr alloys from aqueous solution-ethanol mixtures yields films with potential sweep rate tunable thickness and swelling. The resulting films are antioxidants, and the reservoir of antioxidant moieties is not limited to their surface but also extends into the bulk of the film. In addition, the films produced after a limited energy supply (in the potential window -1 to +1 V vs Ag/AgCl) are strongly antimicrobial against two strains of Pseudomonas aeruginosa without further post-deposition treatment. In addition, their mechanical properties allow them to be detached from their substrates as free-standing films, opening avenues for diverse applications in biomedicine, energy storage, catalysis, sensing, and optoelectronics.

Innovative Microstructure and Morphology Engineering of MOF‐Derived Single‐Atom Sn‐Doped ZnO Nanosheet Showing Highly Sensitive Acetone Sensing

AbstractSingle‐atom materials (SAMs) have garnered widespread attention due to their maximum utilization of active metal atoms for catalytic related applications. However, the facile preparation of oxide materials with high single‐atom loading is still challenging. Herein, derivation of highly tunable metal‐organic frameworks (MOFs) precursor is found to be a potential method for the preparation of single‐atom Sn‐doped ZnO materials for high‐performance chemiresistive sensing applications. Specifically, Sn/Zn‐MOF‐L precursor with interdigitated lamellar morphology is transferred from bimetallic Sn/Zn‐MOF‐B featuring tunable microstructure and morphology through solvent treatment. Utilizing the finely Sn‐doped MOF as precursor, single‐atom Sn‐doped ZnO featuring nanosheet morphology and porous structure is successfully constructed. The as‐prepared single‐atom doped oxides show superior acetone sensing performances, as sensor based on 8% Sn‐doped ZnO demonstrates an astonishing response value of 213 (Ra/Rg) toward 10 ppm acetone and low detection limit of 0.52 ppb. The high sensitivity of Sn‐doped ZnO is attributed to the nanosheet morphology with high specific surface area and the distribution of single‐atom Sn active sites, benefiting from the manipulation of MOF precursor. The method for the preparation of single‐atom loaded oxides and their considerable sensing performance offers a new perspective for the design and application of SAMs.

Diversity of Potential (Bio)technological Applications of Amino Acid-Based Ionic Liquids

This review explores the emerging potential of amino acid-based ionic liquids (AA ILs) in various (bio)applications, emphasizing their unique properties and versatility. It provides a comprehensive analysis of recent advancements, covering applications in drug delivery, catalysis, environmental remediation, and biotechnology. The review also offers an overview of the synthetic methods for preparing AA ILs, highlighting both traditional and innovative approaches, and examines key physicochemical properties—such as biocompatibility, stability, and tunability—that make AA ILs highly attractive for diverse applications. Additionally, challenges hindering their widespread adoption, including high production costs, toxicity concerns, scalability issues, and environmental impact, are discussed. This review concludes with perspectives on future research directions and strategies to overcome these challenges, unlocking the full potential of AA ILs in both scientific and industrial contexts.

Recent Advances in Functionalization of Graphene Oxide and Its Role in Catalytic Organic Transformations: A Comprehensive Review (2018–2024)

AbstractHeterogeneous catalysis has become a key methodology for the sustainable synthesis of organic reactions and heterocyclic compounds. Among various catalysts, graphene oxide (GO) and its functionalized graphene oxide derivatives (fGO) stand out due to their high surface area, mechanical strength, and tunable electronic properties. This review provides a detailed overview of the role of GO in catalysis, emphasizing its structural features, functionalization strategies, and catalytic applications. Specific reactions such as oxidation, reduction, esterification, and heterocyclic synthesis are discussed, with a focus on the superior performance of functionalized graphene oxide (fGO). Challenges like stability and aggregation are explored, alongside potential solutions through chemical, thermal, and electrochemical functionalization. The review also examines future directions, highlighting graphene oxide (GO's) versatility and emerging applications in energy storage, sensors, and biomedical devices. By summarizing current advancements and addressing ongoing challenges, this review underscores the potential of fGO to revolutionize catalytic processes and contribute to sustainable chemistry.

Comprehensive characterization and unprecedented photocatalytic efficacy of TiO2-CuO-La2O3 and TiO2-CuO-Bi2O3 nanocomposites: A novel approach to environmental remediation

In this comprehensive investigation, the properties of TiO2-CuO-La2O3 and TiO2-CuO-Bi2O3 nanocomposites were systematically explored, unveiling their structural, textural, optical, and photocatalytic characteristics. X-ray diffraction analysis identified key solid phases, while scanning electron microscopy revealed consistent surface features, emphasizing the reproducibility of the observed structures. Textural analysis highlighted the mesoporous nature of the nanocomposites, with TiO2-CuO-La2O3 exhibiting a higher surface area, indicating potential for enhanced adsorption and catalytic activity. Optical exploration demonstrated distinctive features, and the incorporation of Bi2O3 reduced the band gap, suggesting applications in photocatalysis or optoelectronics. Further insights into molecular composition, bonding dynamics, and surface defects were provided by FT-IR and photoluminescence spectra. Photocatalysis experiments confirmed the activity of the two nanocomposites, with TiO2-CuO-Bi2O3 demonstrating superior performance. Kinetic studies underscored the importance of reactive species in photocatalytic reactions. Solar irradiation experiments demonstrated the high efficiency of the 500Ti-Cu-Bi7 nanocomposite, with 91% dye degradation, confirming its superior photocatalytic performance and suggesting promising applications in environmental remediation and catalysis.

Deep eutectic solvents (DES): Structure, properties, and cutting-edge applications in green catalysis

Deep eutectic solvents (DES): Structure, properties, and cutting-edge applications in green catalysis

A semisynthetic, multicofactor artificial metalloenzyme retains independent site activity.

Native metalloenzymes are unparalleled in their ability to perform efficient small molecule activation reactions, converting simple substrates into complex products. Most of these natural systems possess multiple metallocofactors to facilitate electron transfer or cascade catalysis. While the field of artificial metalloenzymes is growing at a rapid rate, examples of artificial enzymes that leverage two distinct cofactors remain scarce. In this work, we describe a new class of artificial enzymes containing two different metallocofactors, incorporated through bioorthogonal strategies. Nickel-substituted rubredoxin (NiRd), which is a structural and functional mimic of [NiFe] hydrogenases, is used as a scaffold. Incorporation of a synthetic bimetallic inorganic complex based on a macrocyclic biquinazoline ligand (MMBQ) was accomplished using a novel chelating thioether linker. Neither the structure of the NiRd active site nor the MMBQ were altered upon attachment, and each site retained independent redox activity. Electrocatalysis was observed from each site, with the switchability of the system demonstrated through the use of catalytically inert metal centers. This MMBQ-NiRd platform offers a new avenue to create multicofactor artificial metalloenzymes in a robust system that can be easily tuned both through modifications to the protein scaffold and the synthetic moiety, with applications for redox catalysis and tandem reactivity.

Carboxyethylsilanetriol-Functionalized Al-MIL-53-Supported Palladium Catalyst for Enhancing Suzuki–Miyaura Cross-Coupling Reaction

The application of metal–organic frameworks (MOFs) has attracted increasing attention in organic synthesis. The modification of MOFs can efficiently tailor the structure and improve the property for meeting ongoing demand in various applications, such as the alteration of gas adsorption and separation, catalytic activity, stability, and sustainability or reusability. In this study, carboxyethylsilanetriol (CEST) disodium salt was used as a dual-functional ligand for modified Al-MIL-53 to fabricate CEST-functionalized Al-MIL-53 samples through a hydrothermal reaction of aluminum nitrate, terephthalic acid, and CEST disodium salt by varying the molar ratio of CEST to terephthalic acid and keeping a constant molar ratio of Al3+/-COOH of 1:1. The structure, composition, morphology, pore feature, and stability were characterized by XRD, different spectroscopies, electron microscopy, N2 physisorption, and thermogravimetric analysis. With increasing CEST content, CEST-Al-MIL-53 still preserves an Al-MIL-53-like structure, but the microstructure changed compared with pure Al-MIL-53 due to the integration of CEST. Such a CEST-Al-MIL-53 was used as the support to load Pd particles and afford a catalyst Pd/CEST-Al-MIL-53 for Suzuki–Miyaura C-C cross-coupling reaction of aryl halides and phenylboronic acid under basic conditions. The resulting Pd/CEST-Al-MIL-53 showed a high catalytic activity compared with Pd/Al-MIL-53, due to the nanofibrous structure of silicon species-integrated CEST-Al-MIL-53. The nanofiber microstructure undergoes a remarkable transformation into intricate 3D cross-networks during catalytic reaction, which enables the leachable Pd particles to orientally redeposit and inlay into these networks as the monodisperse spheres and thereby effectively preventing Pd particles from aggregation and leaching, therefore demonstrating a high catalytic performance, long-term stability, and enhanced reusability. Obviously, the integration of CEST into MOFs can effectively prevent the leaching of active Pd species and ensure the re-deposition during catalysis. Moreover, catalytic performance strongly depended on catalyst dosage, temperature, time, solvent, and the type of the substituted group on benzene ring. This work further extends the catalytic application of hybrid metal–organic frameworks.

Catalytic application of copper-doped barium cerate nanoparticles as anode material for robust methanol electro-oxidation

Catalytic application of copper-doped barium cerate nanoparticles as anode material for robust methanol electro-oxidation

Aggregation-induced Electrochemiluminescence of AgNCs Enhanced with Ti3C2Tx AuNPs@MXene Composites for Ultrasensitive Detection of microRNA.

MXene, a two-dimensional nanomaterial, has metal conductivity, high electronegativity, functionalized with surface groups, which makes them has wide applications in catalysis and biosensing. However, studies on the principle of enhanced electro-chemiluminescence (ECL) by MXene composites and the improvement of their performance in catalyzing the ECL reaction are still in their infancy. In this study, gold nanoparticles (AuNPs) are obtained by mild reductive reduction and loaded in situ on the Ti3C2Tx MXene surface to form the composites (AuNPs@MXene). In oxygenated PBS test buffer, AuNPs@MXene enhance the ECL emission of silver nanoclusters (AgNCs) with aggregation-induced electrochemiluminescence (AIECL) properties as luminophore. Approximately 7.5-fold enhancement of ECL signals is obtained by using two ECL enhancement strategies: an efficient AIECL emitter and a co-reaction accelerator. The special nucleic acid structure with "Three Way Junction (TWJ)" enables an ultra-sensitive detection of microRNA, providing an efficient and ultra-sensitive method for microRNA detection. The biosensor achieves a wide detection range of microRNA-21 from 100 aM to 1 nM, with a low detection limit of 31 aM, and exhibits excellent stability, selectivity and high reproducibility in real samples.

Nanopores for DNA and biomolecule analysis: Diagnostic, genomic insights, applications in energy conversion and catalysis.

Recently, nanopores have emerged as highly significant structures with broad applications in diverse scientific and technological fields. They can naturally occur in biological membranes or be artificially fabricated using advanced techniques. Recent advances in nanopore technology have revolutionized genomics by offering previously unheard-of capacities for deoxyribo nucleic acid (DNA) sequencing and analysis. These tiny holes allow individual molecules to be found more easily, allowing for real-time DNA analysis and providing currently unheard-of insights into genetics and diagnostics. By tracking alterations in electrical or ionic currents as biomolecules traverse the pore, nanopores make possible the real-time recognition of other biomolecules, like proteins, nucleic acids, and small molecules, eliminating the need for labeling. This label-free detection potential holds a huge promise in medical diagnostics, genotyping, environmental monitoring, etc. Nanopores have significantly improved DNA sequencing technology such as increment in read length, enabling researchers to sequence entire genomic regions, accuracy can be improved and recent updates have led to a reported increase in total DNA reads, demonstrating the technology's capacity for high-throughput applications via trapping individual DNA strands and monitoring the variations of ionic current as each nucleotide passes across the pore. Finally, nanopore sequencing is well-known as a novel and highly flexible technique for DNA analyses, which has a huge deal of promise in clinical diagnosis and genomics research. Hence, this review article comprehensively explains nanopores for DNA analysis and other biomolecules, their synthesis, and diverse applications.

Heteroleptic (NHC/MIC) Biscarbene Ag(I) and Au(I) Complexes: Synthesis, Characterization and Catalytic Applications.

A series of hetero-biscarbene silver(I) and gold(I) complexes of the general formula [NHC-M-MIC]PF6 (NHC = imidazol-2-ylidene, MIC = 1,2,3-triazol-5-ylidene) have been prepared via the treatment of NHC-M-Cl precursors in reaction with an in situ generated mesoionic carbene (MIC). The new heteroleptic complexes have been fully characterized including NMR spectroscopy, elemental analysis, melting points and single crystal X-ray diffraction. The silver(I) derivatives were employed successfully in the solvent free KA2 (ketone-alkyne-amine) coupling for the preparation of a series of quaternary carbon-containing propargyl amines while, the gold(I) biscarbenes, demonstrated a good performance in the A3 (aldehyde, amine, alkyne) coupling and the benzylic oxidation processes under low catalyst loadings.

Nanoscale Effects in the Room-Temperature UV-Visible Photoluminescence from Silica Particles and Its Cancer Cell Imaging.

Silica nano/microparticles have generated significant interest for the past decades, emerging as a versatile material with a wide range of applications in photonic crystals, bioimaging, chemical sensors, and catalysis. This study focused on synthesizing silica nano/microparticles ranging from 20 nm to 1.2 μm using the Stöber and modified Stöber methods. The particles exhibited photoluminescence emission across a UV-visible range, specifically in the UV (∼290, ∼327, ∼339, and ∼377 nm), blue (∼450 nm), green (∼500 nm), yellow (∼576 nm), and red (∼634 nm) range of the electromagnetic spectrum. These emissions are due to radiative relaxation processes involving oxygen-deficient centers arising due to unrelaxed oxygen vacancies, strong interacting surface silanols, 2-fold coordinated silicon, self-trapped excitons, hydrogen-related species, strain-induced defects, and nonbridging oxygen hole centers excited via two-photon and single photon absorption. The increased PL intensity with a decreasing particle size was attributed to higher concentrations of defect sites in the case of smaller-sized particles. The MTT assay, AO/EB staining, and the DCFDA assay confirmed the biocompatible nature of silica particles in the HepG2 cell line. In addition, the cell viability assay in a normal cell line (HEK293) also showed no substantial cell death. Successful bioimaging of HepG2 cells was performed with silica nano/microparticles, which exhibited blue and green fluorescence, along with Hoechst33258 dye. Even though 20 nm-sized silica particles showed higher PL emission, particles sized above 20 nm showed better fluorescence in HepG2 cells, citing their potential in in vitro bioimaging applications.