Chemical Applications Research Articles

The Spectrum of a Certain Large Block Matrix

Large matrices appear in many applications in computer science, physics, chemistry and many other disciplines. This is because such matrices have the ability to hold huge amounts of memory. On of the main properties that researchers are interested is studying the spectral theory of these matrices. In this paper, we compute the spectrum of a certain large matrix that can serve as an adjacency matrix of a certain clean graph. In particular, we give a full characterization of the eigenvalues and eigenvectors of the intended matrix.

Sulfonated Hydroxyaryl-Tetrazines with Increased pKa for Accelerated Bioorthogonal Click-to-Release Reactions in Cells.

Bioorthogonal reactions that enable switching molecular functions by breaking chemical bonds have gained prominence, with the tetrazine-mediated cleavage of trans-cyclooctene caged compounds (click-to-release) being particularly noteworthy for its high versatility, biocompatibility, and fast reaction rates. Despite several recent advances, the development of highly reactive tetrazines enabling quantitative elimination from trans-cyclooctene linkers remains challenging. In this study, we present the synthesis and application of sulfo-tetrazines, a class of derivatives featuring phenolic hydroxyl groups with increased acidity constants (pKa). This unique property leads to accelerated elimination and complete release of the caged molecules within minutes. Moreover, the inclusion of sulfonate groups provides a valuable synthetic handle, enabling further derivatization into sulfonamides, modified with diverse substituents. Significantly, we demonstrate the utility of sulfo-tetrazines in efficiently activating fluorogenic compounds and prodrugs in living cells, offering exciting prospects for their application in bioorthogonal chemistry.

Sulfonated Hydroxyaryl‐Tetrazines with Increased pKa for Accelerated Bioorthogonal Click‐to‐Release Reactions in Cells

AbstractBioorthogonal reactions that enable switching molecular functions by breaking chemical bonds have gained prominence, with the tetrazine‐mediated cleavage of trans‐cyclooctene caged compounds (click‐to‐release) being particularly noteworthy for its high versatility, biocompatibility, and fast reaction rates. Despite several recent advances, the development of highly reactive tetrazines enabling quantitative elimination from trans‐cyclooctene linkers remains challenging. In this study, we present the synthesis and application of sulfo‐tetrazines, a class of derivatives featuring phenolic hydroxyl groups with increased acidity constants (pKa). This unique property leads to accelerated elimination and complete release of the caged molecules within minutes. Moreover, the inclusion of sulfonate groups provides a valuable synthetic handle, enabling further derivatization into sulfonamides, modified with diverse substituents. Significantly, we demonstrate the utility of sulfo‐tetrazines in efficiently activating fluorogenic compounds and prodrugs in living cells, offering exciting prospects for their application in bioorthogonal chemistry.

Linear Paired Electrolysis Enables Redox-Neutral (3 + 2) Annulation of Benzofuran with Vinyldiazo Compounds.

Electrosynthesis has emerged as a versatile and sustainable tool in organic chemistry, offering an efficient pathway for the construction of complex molecular architectures under mild and environmentally benign conditions. Traditional electrochemical approaches, however, predominantly rely on either anodic oxidation or cathodic reduction, limiting their capacity to achieve redox-neutral transformations using a single electrode. In this work, we introduce a linear paired electrolysis strategy that circumvents these limitations, enabling a redox-neutral (3 + 2) annulation of benzofuran with vinyldiazo compounds. This method facilitates the formation of benzofuran-fused tricyclic scaffolds, which are valuable in synthetic chemistry and medicinal applications. The transformation proceeds through sequential anodic oxidation and cathodic reduction, leveraging a radical cation pathway to deliver polycyclic compounds with high selectivity. The efficiency and mechanism of this process are thoroughly validated using cyclic voltammetry and in situ electrochemical mass spectrometry (EC-MS) and supported by theoretical calculations, shedding light on the potential of redox-neutral electrochemical transformations.

The Great Versatility of Supercritical Fluids in Industrial Processes: A Focus on Chemical, Agri-Food and Energy Applications

Long a thermodynamic curiosity, supercritical fluids (SCFs) have gradually gained ground in today’s life, generating an increasing number of new, efficient processes in diverse industrial sectors and fueling active R&D programs. Indeed, the versatility of SCFs allows them to serve a wide variety of applications. The list includes not only food processing, biofuel production, extraction of biomolecules marketable as medicines, cosmetics and nutraceuticals, but also emerging technologies for the production of electrical power, based on supercritical or transcritical thermodynamic cycles. This jointly authored article will provide a review of important applications covered by our laboratories in the agri-food, chemical and energy sectors. We will then try to detect recent trends and outline future prospects.

C−X (X=C, O, S, N, B, P) Bond Deuteration and Late‐Stage Applications

AbstractPrecise deuterium labeling has gained significant attentions owing to the wide applications in organic synthesis, medicinal chemistry, and organic materials. C−C and C‐heteroatom bonds constitute the skeleton of organic molecules. This review summarizes the advancements on C−C and C‐heteroatom bond deuterations as well as their applications in late‐stage deuterations of natural products and pharmaceutically relevant molecules.

Site-Specific and Fluorescently Enhanced Installation of Post-Translational Protein Modifications via Bifunctional Biarsenical Linker.

To understand how particular post-translational modifications (PTMs) affect the function of a target protein, it is essential to first prepare and investigate the target with the modification at the desired position. This drives the continuous development of site-specific protein modification technologies. Here, we present the chemical synthesis and application of the biarsenical linker SrtCrAsH-EDT2, which has a dual labeling functionality. This linker, containing a sortase A recognition motif, can be conjugated with any protein containing the LPXTG motif at the C terminus, such as ubiquitin and the SUMO tag, and then attached to a protein of interest (POI) containing a terminal or bipartite (intramolecularly placed) tetracysteine motif. This modification of the POI facilitates the straightforward and rapid incorporation of PTMs, which are further highlighted by the fluorescent biarsenical probe. Consequently, this directly correlates proteins' physical properties and cellular roles under various physiological conditions or in disease states. The proposed one-pot labeling methodology can be utilized to explore the effects of PTMs on proteins, affecting their structure, function, localization, and interactions within the cellular environment. Understanding these effects is crucial for uncovering the complex mechanisms that regulate cellular function and dysfunction.

Sympathetic Mechanism for Vibrational Condensation Enabled by Polariton Optomechanical Interaction.

We demonstrate a macrocoherent regime in exciton-polariton systems, where nonequilibrium polariton Bose-Einstein condensation coexists with macroscopically occupied vibrational states. Strong exciton-vibration coupling induces an effective optomechanical interaction between cavity polaritons and vibrational degrees of freedom of molecules, leading to vibrational amplification in a resonant blue-detuned configuration. This interaction provides a sympathetic mechanism to achieve vibrational condensation with potential applications in cavity-controlled chemistry, nonlinear, and quantum optics.

IPr*F - Highly Hindered, Fluorinated N-Heterocyclic Carbenes.

The introduction of fluorine atom has attracted considerable interest in molecular design owing to the high electronegativity and the resulting polarization of carbon-fluorine bonds. Simultaneously, sterically-hindered N-heterocyclic carbenes (NHCs) have received major interest due to high stabilization of the reactive metal centers, which has paved the way for the synthesis of stable and reactive organometallic compounds with broad applications in main group chemistry, inorganic synthesis and transition-metal-catalysis. Herein, we report the first class of sterically-hindered, fluorinated N-heterocyclic carbenes. These ligands feature variable fluorine substitution at the N-aromatic wingtip, permitting to rationally vary steric and electronic characteristics of the carbene center imparted by the fluorine atom. An efficient, one-pot synthesis of fluorinated IPr*F ligands is presented, enabling broad access of academic and industrial researchers to the fluorinated ligands. The evaluation of steric, electron-donating and π-accepting properties as well as coordination chemistry to Au(I), Rh(I) and Se is presented. Considering the unique properties of carbon-fluorine bonds, we anticipate that this novel class of fluorinated carbene ligands will find widespread application in stabilizing reactive metal centers.

Exploring unsteady radiative nanofluid dynamics: Thomson–Troian wall slip effects on a stretching rotating disk

AbstractFluid flow over rotating disk possesses many potential application in many engineering, biological, electrical, and chemical. Along with nanoparticles flow become more enriched in terms of chemical and physical properties. This study investigates the laminar, unsteady, incompressible flow of a water‐based nanofluid above a rotating, stretchable disk. The nanofluid consists of three distinct nanoparticles (magnetite), (copper), and (silver), under the influence of radiation. The behavior of the nanofluid is modeled using the Tiwari and Das model with generalized slip on the disk surface. The new facet of study is to examines the effects of different parameters including stretching, slip, radiation, skin friction, and Nusselt numbers on the flow dynamics. The fluid motion is driven by the rotation and stretching of the disk. Through appropriate similarity transformations, the governing partial differential equations for the flow and thermal transport processes are transformed into a set of coupled ordinary differential equations. These equations are then numerically solved using bvp4c method in MATLAB. The results indicate that velocities in both the radial and axial directions increase with rising stretching parameters, due which skin friction coefficient mount by . And, Nusselt number of fluid surge by increasing volume fraction of , , nanoparticles respectively. Additionally, the temperature increases with increment in the radiation parameter . An increase in the slip parameter's value results in a reduction in both radial and axial velocities.

Selective Oxidation of p-Cymene over Mesoporous LaCoO3 by Introducing Oxygen Vacancies.

The liquid-phase catalytic oxidation of p-cymene to 4-methylacetophenone is an industrially significant reaction. However, the targeted oxidation of a specific C-H bond of p-cymene is extremely difficult due to there being many branched chains in p-cymene. In here, we designed a simple method to synthesize mesoporous LaCoO3 catalysts with rich oxygen vacancy (Oov) sites. The as-prepared mesoporous LaCoO3 after 550 °C calcination (mLaCoO3) exhibits remarkable catalytic activity for solvent-free oxidation of the p-cymene reaction, with a selectivity of over 80.1% selectivity for 4-methylacetophenone and a conversion of 50.2% for p-cymene (120 °C, 3 MPa). Besides, recycling studies have demonstrated that the mLaCoO3 catalysts can be reused ten times in the aerobic oxidation of the p-cymene reaction without significant catalytic activity reduce. The experimental and characterization results indicated that the mesoporous structure of the catalyst is conducive to the generation of surface Oov, which can properly facilitate ion spread during the catalytic process and afford enough O2 for intermediate species, thus is beneficial for the generation of 4-methylacetophenone. This work demonstrates that the selectivity oxide p-cymene with an O2 employing mLaCoO3 catalyst is highly promising for chemical industrial applications.

Structural and Electronic Factors Controlling the Efficiency and Rate of Intersystem Crossing to the Triplet State in Thiophene Polycyclic Derivatives.

Thiophene polycyclic derivatives are widely used in organic light-emitting diodes, photovoltaics, and medicinal chemistry applications. Understanding the electronic and structural factors controlling their intersystem crossing rates is paramount for these applications to be successful. This study investigates the photophysical, electronic structure, and excited state dynamics of 1,2-benzodiphenylene sulfide, benzo[b]naphtho[1,2-d]thiophene, and benzo[b]naphtho[2,3-d]thiophene in polar aprotic and non-polar solvents. Steady-state absorption and emission spectroscopy, femtosecond transient absorption spectroscopy, and DFT and TD-DFT calculations are employed. Low fluorescence quantum yields of 1.2 to 2.7 % are measured in acetonitrile and cyclohexene, evidencing that the primary relaxation pathways in these thiophene derivatives are nonradiative. Linear interpolation of internal coordinates calculations predict that an S-C bond elongation reaction coordinate facilitates the efficient intersystem crossing to the T1 state. Excitation of 1,2-benzodiphenylene sulfide and benzo[b]naphtho[1,2-d]thiophene at 350 nm or benzo[b]naphtho[2,3-d]thiophene at 365 nm, populates the lowest-energy 1ππ* state, which relaxes to the 1ππ* minimum in tens of picoseconds or intersystem crosses to the triplet manifold in ca. 500 ps to 1.1 ns depending on the position at which the benzene rings are added. Excitation at 266 nm does not affect the intersystem crossing rates. Laser photodegradation experiments demonstrate that the thiophene polycyclic derivatives are highly photostable.

Analyzing the modified symmetric division deg index: mathematical bounds and chemical relevance

Abstract The modified symmetric division deg (MSD) index of a graph G is precisely defined as MSD ( G ) = ∑ j ∼ k 1 2 d j d k + d k d j , where d j and d k represent the degrees of j and k respectively. In this paper, we present precise bounds for the modified symmetric division deg index, expressed in the relation to the minimum and maximum degrees, the order and size of the graph, the number of pendant vertices and the minimum degree of a non-pendant vertex, the forgotten topological index, the modified second Zagreb index. We determine the upper bounds for the modified symmetric division deg index of unicyclic, bicyclic and k-cyclic graphs. Moreover, upon analyzing the modified symmetric division deg index, we observe its correlation with other well-known indices and its chemical applicability on the molecular graphs of octane isomers. At the end, we find the chemical applicability of the modified symmetric division deg index on benzenoid hydrocarbons and observe that the modified symmetric division deg index has a very strong correlation with the physical properties of benzenoid hydrocarbons.

Streamlined Synthesis of Ellagitannins: Site-Selective Functionalization of the Glucose Core and Stereodivergent Construction of the Hexahydroxydiphenoic Groups.

Ellagitannins are a class of plant polyphenols with a structural diversity of around 1000. Because those with attractive biological activities have been reported, synthetic studies have been performed. The purpose of this perspective is to provide an outlook toward future developments on ellagitannin chemistry and medicinal applications by overviewing synthetic studies. In particular, we summarize recent synthetic efforts of ellagitannins via functionalization of the glucose core and stereodivergent construction of the characteristic hydroxydiphenoic groups. The development of chemical probes utilizing natural ellagitannins is also introduced.

Upcycling of waste polyethylene terephthalate (PET) into CoFe@C for highly efficient PV-driven bifunctional seawater splitting via a “waste materialization” strategy

Developing green and efficient techniques to convert plastic wastes into functional materials is attractive and remains highly challenging. This study employs a hydrothermal combining with pyrolysis process for constructing a Co3Fe1@C heterostructure from the polyethylene terephthalate (PET) waste-mediated metal-organic frameworks. The as-obtained Co3Fe1@C shows a core-shell structure and possesses good performance towards water electrolysis. The Co3Fe1@C can attain the current density of 100 mA cm−2 with an overpotential of 250 mV for oxygen evolution reaction (OER). In addition, the bifunctional Co3Fe1@C can realize the overall seawater electrolysis at 50 mA cm−2 with good stability for 280 h driven by a 2.2 V commercial silicon solar cell. Overall, this study demonstrates a green chemistry approach to simultaneous plastic waste upcycling and cost-effective electrocatalyst fabrication, which may stimulate further research on the “waste materialization” approach to converting solid waste into highly efficient catalysts for various chemistry and energy industry applications.

SERS Sensor for Acetylcholine Detection Based on Covalent Organic Framework Hybridized Gold Nanoparticles As Nanozymes.

An innovative and potent nanozyme with reductase-like activity was developed by integrating the in situ synthesis of gold nanoparticles (Au NPs) onto the surface of a covalent organic framework (COF). Based on the reductase-like activity of the COF-hybridized Au NPs, this nanozyme could efficiently catalyze the reduction of 4-nitrophenol (4-NPH). Moreover, the prepared nanohybrid was utilized as an excellent surface-enhanced Raman scattering (SERS) substrate for highly sensitive SERS detection by combining the excellent adsorption properties of COFs and the large number of Raman hotspots between the high-density Au NPs. For the first time, 4-NPH was used as an SERS marker to detect the electron receptor acetylcholine (Ach), with high sensitivity; Ach acted as an inhibitor in this catalytic reaction. The linear range of Ach was 1.0 pM to 10 nM, the correlation coefficient was 0.993, the detection limit was approximately 0.3 pM with a signal-to-noise ratio (s/n) of 3, and the acceptable recovery in the serum was 97.2% to 104.5%. The results from this study show that the nanozyme-SERS system has great potential for chemical and bioassay applications.

Experimental Elucidation of a Cubane Water Cluster in the Hydrophobic Cavity of UiO-66.

Nanoscale water plays a pivotal role in determining the properties and functionalities of materials, and the precise control of its quantity and atomic-scale ordered structure is a focal point in nanotechnology and chemistry. Several studies have theoretically discussed the nano-ordered ice within one- or two-dimensional space and without confinement through hydrogen bonds. In particular, the water cluster has been predicted to play a significant role in biomolecules or functional nanomaterials; however, there has been little experimental evidence for their presence in hydrophobic cavities. In this study, the cubane water octamer - the most stable isomer among small water clusters - was detected within the hydrophobic cavities of UiO-66 metal-organic frameworks, revealing the presence of the smallest ice in their hydrophobic cavity, in the absence of hydrogen bonding. This observation contrasts earlier examples of water clusters confined within nanocavities through hydrogen bonds and provides experimental evidence for water-cluster capturing within hydrophobic cavities. Consequently, our renewed understanding of hydrophilicity and hydrophobicity warrants a design re-evaluation of materials for chemical applications, including fuel cells, water harvesting, catalysts, and batteries.

Holistic exploration of silver nanoparticles synthesized from Carthamus oxycantha leaf extracts: Characterization and assessment of antioxidant, anti-α-amylase, and anti-cholinesterase activities using comprehensive statistical methods

In the burgeoning field of nanotechnology, plant-mediated nanoparticles (NPs) have attracted significant attention due to their small size, favorable chemical properties, and eco-friendly nature. We utilized Carthamus oxycantha leaf extract to synthesize silver nanoparticles (AgNPs) and evaluate their potential as antioxidants and inhibitors of acetylcholinesterase (AChE) and alpha-amylase (α-amylase). The AgNPs were characterized using advanced techniques. The UV–Vis spectrum recorded at 410 nm, with an absorbance of 2.3 a.u., confirmed the presence of AgNPs. Fourier transform infrared spectroscopy (FT-IR) indicated that functional groups from the extract were attached to the AgNP surface, aiding in their formation and stabilization. X-ray diffraction analysis (XRD) revealed four major peaks at 37, 43, 64, and 77, confirming AgNP synthesis. Scanning electron microscopy (SEM) showed that 80 % of the AgNPs were spherical, measuring 25–50 nm, while energy dispersive X-ray (EDX) analysis indicated that silver constituted 83 % of the material. The AgNPs demonstrated significant scavenging activity: 59.3 % with ABTS, 67.2 % with ammonium molybdate, 60.35 % with DPPH, 65.2 % with ferric chloride, and 55.2 % with H2O2. Both α-amylase and AChE were inhibited by AgNPs, exhibiting uncompetitive inhibition characteristics. For glucophage, Km decreased from 143 to 75 µg, and Vmax decreased from 45 % to 72 % as concentrations increased from 50 to 150 µg. The Km of AgNPs decreased from 25 to 17 µg, and Vmax decreased from 16 % to 37 %. The extract showed noncompetitive inhibition against α-amylase, while AgNPs caused noncompetitive inhibition in AChE. These findings highlight the potential of AgNPs as therapeutic agents for managing oxidative stress and enzyme-related disorders, paving the way for future research and applications in medicinal chemistry.

Deep eutectic solvent as stationary phase for flow analysis: Automated trace metal determination in food products

BackgroundDeep eutectic solvents (DES) have emerged as effective solvents that address many challenges in analytical chemistry, particularly in microextraction. However, until now, their use has been primarily focused on extraction processes. This has significantly limited their application in analytical chemistry, especially in flow analysis, where the high viscosity of DES has made their use difficult. ResultsThis paper presents a novel DES-based liquid-liquid microextraction approach for the separation and determination of trace metals in foods using an automated flow analysis system. In this study, a DES composed of thymol and thionalide was first prepared and thoroughly characterized by spectroscopic (IR, NMR) and differential scanning calorimetry techniques. The COSMO-SAC model was employed to predict the solubility of metal salts (Cu, Cd, Pb, and Hg) in the new DES. The solvent was applied to glass fiber as a stationary phase in an extraction column in a flow analysis. After microwave digestion of food samples, metals were extracted by this DES in an automated mode and subsequently eluted with an aqueous thiourea solution. The procedure demonstrated limits of detection (LOD) of 6 μg kg−1 for mercury, 4 μg kg−1 for copper, 6 μg kg−1 for lead and 0.6 μg kg−1 for cadmium. SignificanceThis study represents the first application of a DES-based stationary phase in automated flow analysis, significantly enhancing extraction efficiency. The procedure enables precise and reliable determination of trace metals in food products, aligning with green chemistry principles by minimizing waste.

Applications of Diels-Alder Chemistry in Biomaterials and Drug Delivery.

Recent studies, leveraging click chemistry reactions, have significantly advanced the fields of biomaterials and drug delivery. Of these click reactions, the Diels-Alder cycloaddition is exceptionally valuable for synthetic organic chemistry and biomaterial design, as it occurs under mild reaction conditions and can undergo a retrograde reaction, under physiologically relevant conditions, to yield the initial reactants. In this review, potential applications of the Diels-Alder reaction are explored within the nexus of biomaterials and drug delivery. This includes an emphasis on key platforms such as polymers, nanoparticles, and hydrogels which utilize Diels-Alder for drug delivery, functionalized surfaces, bioconjugation, and other diverse applications. Specifically, this review will focus on the use of Diels-Alder biomaterials in applications of tissue engineering and cancer therapies, while providing a discussion of the advantages, platforms, and applications of Diels-Alder click chemistry.