Molecules

12 pages, 2733 KiB

Open AccessArticle

A New BODIPY-Based Receptor for the Fluorescent Sensing of Catecholamines

by Roberta Puglisi, Alessia Cavallaro, Andrea Pappalardo, Manuel Petroselli, Rossella Santonocito and Giuseppe Trusso Sfrazzetto

Molecules 2024, 29(15), 3714; https://doi.org/10.3390/molecules29153714 - 5 Aug 2024

Viewed by 648

Abstract

The human body synthesizes catecholamine neurotransmitters, such as dopamine and noradrenaline. Monitoring the levels of these molecules is crucial for the prevention of important diseases, such as Alzheimer’s, schizophrenia, Parkinson’s, Huntington’s, attention-deficit hyperactivity disorder, and paragangliomas. Here, we have synthesized, characterized, and functionalized [...] Read more.

The human body synthesizes catecholamine neurotransmitters, such as dopamine and noradrenaline. Monitoring the levels of these molecules is crucial for the prevention of important diseases, such as Alzheimer’s, schizophrenia, Parkinson’s, Huntington’s, attention-deficit hyperactivity disorder, and paragangliomas. Here, we have synthesized, characterized, and functionalized the BODIPY core with picolylamine (BDPy-pico) in order to create a sensor capable of detecting these biomarkers. The sensing properties of the BDPy-pico probe in solution were studied using fluorescence titrations and supported by DFT studies. Catecholamine sensing was also performed in the solid state by a simple strip test, using an optical fiber as the detector of emissions. In addition, the selectivity and recovery of the sensor were assessed, suggesting the possibility of using this receptor to detect dopamine and norepinephrine in human saliva. Full article

(This article belongs to the Special Issue Boron Dipyrromethene (BODIPY) Dyes and Their Derivatives)

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22 pages, 28263 KiB

Open AccessArticle

Investigation of the Sensing Properties of Lanthanoid Metal–Organic Frameworks (Ln-MOFs) with Terephthalic Acid

by Denitsa Elenkova, Yana Dimitrova, Martin Tsvetkov, Bernd Morgenstern, Maria Milanova, Dimitar Todorovsky and Joana Zaharieva

Molecules 2024, 29(15), 3713; https://doi.org/10.3390/molecules29153713 - 5 Aug 2024

Viewed by 633

Abstract

The solvothermal synthesis of LnCl₃^.nH₂O with terephthalic acid (benzene-1,4-dicarboxylic acid, H₂BDC) produced metal–organic frameworks (LnBDC), [Ln₂(BDC)₃(H₂O)₄]_∞, where Ln = Sm, Eu, Tb, and Dy. The materials [...] Read more.

The solvothermal synthesis of LnCl₃^.nH₂O with terephthalic acid (benzene-1,4-dicarboxylic acid, H₂BDC) produced metal–organic frameworks (LnBDC), [Ln₂(BDC)₃(H₂O)₄]_∞, where Ln = Sm, Eu, Tb, and Dy. The materials obtained were characterized by a number of physico-chemical techniques. The influence of the ionic radius of the lanthanides on the microstructural characteristics of the Ln-MOFs was evaluated by performing Rietveld refinement. The MOFs obtained were tested as fluorescent sensors for numerous cations and anions in water. The highly luminescent EuBDC and TbBDC demonstrated multi-responsive luminescence sensing functions to detect Ag(I), Fe(III), Cr(III), and Cr(VI), which are essential for their environmental applications. By applying the non-linear Stern–Volmer equation, the fluorescent quenching mechanism was determined. The stability of the obtained materials in water in a wide pH range (acidity pH = 4 and alkalinity pH = 9 solutions) was confirmed. Full article

(This article belongs to the Special Issue Rare Earth Based Luminescent Materials)

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21 pages, 6341 KiB

Open AccessArticle

Functionalization of Artwork Packaging Materials Utilizing Ag-Doped TiO₂ and ZnO Nanoparticles

by Tilde de Caro, Roberta Grazia Toro, Luminita Cassone, Francesca Irene Barbaccia, Camilla Zaratti, Irene Angela Colasanti, Mauro Francesco La Russa and Andrea Macchia

Molecules 2024, 29(15), 3712; https://doi.org/10.3390/molecules29153712 - 5 Aug 2024

Viewed by 533

Abstract

Most of the artworks stored in museums are often kept in inappropriate climatic and environmental conditions that facilitate the formation and growth of microorganisms, such as fungi, which are responsible for many types of biodegradation phenomena. To mitigate and prevent these deteriorative processes, [...] Read more.

Most of the artworks stored in museums are often kept in inappropriate climatic and environmental conditions that facilitate the formation and growth of microorganisms, such as fungi, which are responsible for many types of biodegradation phenomena. To mitigate and prevent these deteriorative processes, functionalized packaging materials can be used for the storage and handling of artworks. The aim of this study was to develop a potential anti-biodeterioration coating suitable for packaging purposes. TiO₂ and ZnO doped with different amounts of Ag (0.5 wt%, 1 wt%, and 3 wt%) were synthesized and dispersed in polyvinyl alcohol (PVA) and acrylic resin (Paraloid B72), then applied on different types of packaging materials (cellulose and the high-density spunbound polyethylene fiber Tyvek^®, materials that are frequently used as packaging in museums). Analytical investigations (SEM/EDS, Raman, FTIR, and XRD) were employed to assess dispersion on the packaging material. Furthermore, resistance against biodeteriogens was assessed using Cladosporium sp., a bioluminometer, to define the biocidal efficacy. Full article

(This article belongs to the Special Issue Advances in Analytical Strategies to Study Cultural Heritage Samples, 2nd Edition)

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30 pages, 9980 KiB

Open AccessArticle

Enhanced Removal of Cd(II) Ions from Aqueous Media via Adsorption on Facilely Synthesized Copper Ferrite Nanoparticles

by Nada S. Al-Kadhi and Maram T. Basha

Molecules 2024, 29(15), 3711; https://doi.org/10.3390/molecules29153711 - 5 Aug 2024

Viewed by 655

Abstract

In this study, magnetic copper ferrite (CuFe₂O₄) nanoparticles were synthesized via the Pechini sol-gel method and evaluated for the removal of Cd(II) ions from aqueous solutions. PF600 and PF800 refer to the samples that were synthesized at 600 °C [...] Read more.

In this study, magnetic copper ferrite (CuFe₂O₄) nanoparticles were synthesized via the Pechini sol-gel method and evaluated for the removal of Cd(II) ions from aqueous solutions. PF600 and PF800 refer to the samples that were synthesized at 600 °C and 800 °C, respectively. Comprehensive characterization using FTIR, XRD, FE-SEM, HR-TEM, and EDX confirmed the successful formation of CuFe₂O₄ spinel structures, with crystallite sizes of 22.64 nm (PF600) and 30.13 nm (PF800). FE-SEM analysis revealed particle diameters of 154.98 nm (PF600) and 230.05 nm (PF800), exhibiting spherical and irregular shapes. HR-TEM analysis further confirmed the presence of aggregated nanoparticles with average diameters of 52.26 nm (PF600) and 98.32 nm (PF800). The PF600 and PF800 nanoparticles exhibited exceptional adsorption capacities of 377.36 mg/g and 322.58 mg/g, respectively, significantly outperforming many materials reported in the literature. Adsorption followed the Langmuir isotherm model and pseudo-second-order kinetics, indicating monolayer adsorption and strong physisorption. The process was spontaneous, exothermic, and predominantly physical. Reusability tests demonstrated high adsorption efficiency across multiple cycles when desorbed with a 0.5 M ethylenediaminetetraacetic acid (EDTA) solution, emphasizing the practical applicability of these nanoparticles. The inherent magnetic properties of CuFe₂O₄ facilitated easy separation from the aqueous medium using a magnet, enabling efficient and cost-effective recovery of the adsorbent. These findings highlight the potential of CuFe₂O₄ nanoparticles, particularly PF600, for the effective and sustainable removal of Cd(II) ions from water. Full article

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13 pages, 2091 KiB

Open AccessArticle

A Formal Synthesis of (+)-Hannokinol Using a Chiral Horner–Wittig Reagent

by Michael Tapera, Federica Borghi, Jan Lukas Mayer-Figge, Fabia Mittendorf, Ibrahim-Ethem Celik, Adrián Gómez-Suárez and Stefan F. Kirsch

Molecules 2024, 29(15), 3710; https://doi.org/10.3390/molecules29153710 - 5 Aug 2024

Viewed by 508

Abstract

Herein, we report a concise and efficient formal synthesis of (+)-hannokinol. Key to this new strategy is the use of a chiral Horner–Wittig reagent, readily available from 2-deoxy-D-ribose, to introduce the chiral 1,3-diol motif. Full article

(This article belongs to the Section Organic Chemistry)

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15 pages, 2677 KiB

Open AccessArticle

Adsorption of Bichromate and Arsenate Anions by a Sorbent Based on Bentonite Clay Modified with Polyhydroxocations of Iron and Aluminum by the “Co-Precipitation” Method

by Bakytgul Kussainova, Gaukhar Tazhkenova, Ivan Kazarinov, Marina Burashnikova, Aisha Nurlybayeva, Gulnaziya Seitbekova, Saule Kantarbayeva, Nazgul Murzakasymova, Elvira Baibazarova, Dinara Altynbekova, Assem Shinibekova and Aidana Bazarkhankyzy

Molecules 2024, 29(15), 3709; https://doi.org/10.3390/molecules29153709 - 5 Aug 2024

Viewed by 493

Abstract

The physicochemical properties of natural bentonite and its sorbents were studied. It has been established the modification of natural bentonites using polyhydroxoxides of iron (III) (mod.1_Fe_5-c) and aluminum (III) (mod.1_Al_5-c) by the “co-precipitation” method led to changes in their chemical composition, structure, and [...] Read more.

The physicochemical properties of natural bentonite and its sorbents were studied. It has been established the modification of natural bentonites using polyhydroxoxides of iron (III) (mod.1_Fe_5-c) and aluminum (III) (mod.1_Al_5-c) by the “co-precipitation” method led to changes in their chemical composition, structure, and sorption properties. It was shown that modified sorbents based on natural bentonite are finely porous (nanostructured) objects with a predominance of pores of 1.5–8.0 nm in size. The modification of bentonite with iron (III) and aluminum compounds by the “co-precipitation” method also leads to an increase in the sorption capacity of the obtained sorbents with respect to bichromate and arsenate anions. A kinetic analysis showed that, at the initial stage, the sorption process was controlled by an external diffusion factor, that is, the diffusion of the sorbent from the solution to the liquid film on the surface of the sorbent. The sorption process then began to proceed in a mixed diffusion mode when it limited both the external diffusion factor and the intra-diffusion factor (diffusion of the sorbent to the active centers through the system of pores and capillaries). To clarify the contribution of the chemical stage to the rate of adsorption of bichromate and arsenate anions by the sorbents under study, kinetic curves were processed using equations of chemical kinetics (pseudo-first-order, pseudo-second-order, and Elovich models). It was found that the adsorption of the studied anions by the modified sorbents based on natural bentonite was best described by a pseudo-second-order kinetic model. The high value of the correlation coefficient for the Elovich model (R² > 0.9) allows us to conclude that there are structural disorders in the porous system of the studied sorbents, and their surfaces can be considered heterogeneous. Considering that heterogeneous processes occur on the surface of the sorbent, it is natural that all surface properties (structure, chemical composition of the surface layer, etc.) play an important role in anion adsorption. Full article

(This article belongs to the Special Issue Zeolites and Porous Materials: Synthesis, Properties and Applications)

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13 pages, 6204 KiB

Open AccessArticle

Enhanced Fire Safety of Energy-Saving Foam by Self-Cleavage CO₂ Pre-Combustion and Phosphorus Release Post-Combustion

by Fengyun Sun, Lijun Wang, Tiantian Gao, Yuanyuan Zhong and Kefa Ren

Molecules 2024, 29(15), 3708; https://doi.org/10.3390/molecules29153708 - 5 Aug 2024

Viewed by 446

Abstract

Rigid polyurethane foam (RPUF) is widely utilized in construction and rail transportation due to its lightweight properties and low thermal conductivity, contributing to energy conservation and emission reduction. However, the inherent flammability of RPUF presents significant challenges. Delaying the time to ignition and [...] Read more.

Rigid polyurethane foam (RPUF) is widely utilized in construction and rail transportation due to its lightweight properties and low thermal conductivity, contributing to energy conservation and emission reduction. However, the inherent flammability of RPUF presents significant challenges. Delaying the time to ignition and preventing flame spread post-combustion is crucial for ensuring sufficient evacuation time in the event of a fire. Based on this principle, this study explores the efficacy of using potassium salts as a catalyst to promote the self-cleavage of RPUF, generating substantial amounts of CO₂, thereby reducing the local oxygen concentration and delaying ignition. Additionally, the inclusion of a reactive flame retardant (DFD) facilitates the release of phosphorus-oxygen free radicals during combustion, disrupting the combustion chain reaction and thus mitigating flame propagation. Moreover, potassium salt-induced catalytic carbonization and phosphorus derivative cross-linking enhance the condensed phase flame retardancy. Consequently, the combined application of potassium salts and DFD increases the limiting oxygen index (LOI) and reduces both peak heat release rate (PHRR) and total heat release (THR). Importantly, the incorporation of these additives does not compromise the compressive strength or thermal insulation performance of RPUF. This integrated approach offers a new and effective strategy for the development of flame retardant RPUF. Full article

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11 pages, 3808 KiB

Open AccessArticle

Gold Nanoparticle Mesoporous Carbon Composite as Catalyst for Hydrogen Evolution Reaction

by Erik Biehler, Qui Quach and Tarek M. Abdel-Fattah

Molecules 2024, 29(15), 3707; https://doi.org/10.3390/molecules29153707 - 5 Aug 2024

Viewed by 480

Abstract

Increased environmental pollution and the shortage of the current fossil fuel energy supply has increased the demand for eco-friendly energy sources. Hydrogen energy has become a potential solution due to its availability and green combustion byproduct. Hydrogen feedstock materials like sodium borohydride (NaBH [...] Read more.

Increased environmental pollution and the shortage of the current fossil fuel energy supply has increased the demand for eco-friendly energy sources. Hydrogen energy has become a potential solution due to its availability and green combustion byproduct. Hydrogen feedstock materials like sodium borohydride (NaBH₄) are promising sources of hydrogen; however, the rate at which the hydrogen is released during its reaction with water is slow and requires a stable catalyst. In this study, gold nanoparticles were deposited onto mesoporous carbon to form a nano-composite catalyst (AuNP-MCM), which was then characterized via transmission electron microscopy (TEM), powder X-ray diffraction (P-XRD), and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). The composite’s catalytic ability in a hydrogen evolution reaction was tested under varying conditions, including NaBH₄ concentration, pH, and temperature, and it showed an activation of energy of 30.0 kJ mol⁻¹. It was determined that the optimal reaction conditions include high NaBH4 concentrations, lower pH, and higher temperatures. This catalyst, with its stability and competitively low activation energy, makes it a promising material for hydrogen generation. Full article

(This article belongs to the Special Issue Two-Dimensional Materials: From Synthesis to Applications)

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21 pages, 3151 KiB

Open AccessArticle

Establishing the Thermodynamic Cards of Dipine Models’ Oxidative Metabolism on 21 Potential Elementary Steps

by Guang-Bin Shen, Shun-Hang Gao, Yan-Wei Jia, Xiao-Qing Zhu and Bao-Chen Qian

Molecules 2024, 29(15), 3706; https://doi.org/10.3390/molecules29153706 - 5 Aug 2024

Viewed by 627

Abstract

Dipines are a type of important antihypertensive drug as L-calcium channel blockers, whose core skeleton is the 1,4-dihydropyridine structure. Since the dihydropyridine ring is a key structural factor for biological activity, the thermodynamics of the aromatization dihydropyridine ring is a significant feature parameter [...] Read more.

Dipines are a type of important antihypertensive drug as L-calcium channel blockers, whose core skeleton is the 1,4-dihydropyridine structure. Since the dihydropyridine ring is a key structural factor for biological activity, the thermodynamics of the aromatization dihydropyridine ring is a significant feature parameter for understanding the mechanism and pathways of dipine metabolism in vivo. Herein, 4-substituted-phenyl-2,6-dimethyl-3,5-diethyl-formate-1,4-dihydropyridines are refined as the structurally closest dipine models to investigate the thermodynamic potential of dipine oxidative metabolism. In this work, the thermodynamic cards of dipine models’ aromatization on 21 potential elementary steps in acetonitrile have been established. Based on the thermodynamic cards, the thermodynamic properties of dipine models and related intermediates acting as electrons, hydrides, hydrogen atoms, protons, and two hydrogen ions (atoms) donors are discussed. Moreover, the thermodynamic cards are applied to evaluate the redox properties, and judge or reveal the possible oxidative mechanism of dipine models. Full article

(This article belongs to the Section Organic Chemistry)

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13 pages, 3585 KiB

Open AccessArticle

Anti-Inflammatory Effect of Xanthones from Hypericum beanii on Macrophage RAW 264.7 Cells through Reduced NO Production and TNF-α, IL-1β, IL-6, and COX-2 Expression

by Wei Ma, Fu-Cai Ren, Xue-Ru Wang and Ning Li

Molecules 2024, 29(15), 3705; https://doi.org/10.3390/molecules29153705 - 5 Aug 2024

Viewed by 574

Abstract

Hypericum beanii N. Robson, a perennial upright herb, predominantly inhabits temperate regions. This species has been utilized for the treatment of various inflammation-related diseases. One new xanthone 3,7-dihydroxy-1,6-dimethoxyxanthone (1) and twenty-three known xanthones (2–24) were isolated from [...] Read more.

Hypericum beanii N. Robson, a perennial upright herb, predominantly inhabits temperate regions. This species has been utilized for the treatment of various inflammation-related diseases. One new xanthone 3,7-dihydroxy-1,6-dimethoxyxanthone (1) and twenty-three known xanthones (2–24) were isolated from the aerial parts of H. beanii. The structure of the new compound was determined based on high-resolution electrospray ionization mass spectroscopy (HR-ESIMS), nuclear magnetic resonance (NMR), Infrared Spectroscopy (IR), ultraviolet spectrophotometry (UV) spectroscopic data. The anti-inflammatory effects of all the isolates were assessed by measuring the inhibitory effect on nitric oxide (NO) production in LPS-stimulated RAW 264.7 macrophages. Compounds 3,4-dihydroxy-2-methoxyxanthone (15), 1,3,5,6-tetrahydroxyxanthone (19), and 1,3,6,7-tetrahydroxyxanthone (22) exhibited significant anti-inflammatory effects at a concentration of 10 μM with higher potency compared to the positive control quercetin. Furthermore, compounds 15, 19, and 22 reduced inducible NO synthase (iNOS), tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), IL-6, and cyclooxygenase 2 (COX-2) mRNA expression in the LPS-stimulated RAW 264.7 macrophages, suggesting that these compounds may mitigate the synthesis of the aforementioned molecules at the transcriptional level, provisionally confirming their anti-inflammatory efficacy. Full article

(This article belongs to the Special Issue Isolation, Identification and Application of Biologically Active Natural Products—Second Edition)

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16 pages, 1534 KiB

Open AccessReview

Recent Progress in Photothermal, Photodynamic and Sonodynamic Cancer Therapy: Through the cGAS-STING Pathway to Efficacy-Enhancing Strategies

by Kelan Fang, Huiling Zhang, Qinghong Kong, Yunli Ma, Tianchan Xiong, Tengyao Qin, Sanhua Li and Xinting Zhu

Molecules 2024, 29(15), 3704; https://doi.org/10.3390/molecules29153704 - 5 Aug 2024

Viewed by 734

Abstract

Photothermal, photodynamic and sonodynamic cancer therapies offer opportunities for precise tumor ablation and reduce side effects. The cyclic guanylate adenylate synthase-stimulator of interferon genes (cGAS-STING) pathway has been considered a potential target to stimulate the immune system in patients and achieve a sustained [...] Read more.

Photothermal, photodynamic and sonodynamic cancer therapies offer opportunities for precise tumor ablation and reduce side effects. The cyclic guanylate adenylate synthase-stimulator of interferon genes (cGAS-STING) pathway has been considered a potential target to stimulate the immune system in patients and achieve a sustained immune response. Combining photothermal, photodynamic and sonodynamic therapies with cGAS-STING agonists represents a newly developed cancer treatment demonstrating noticeable innovation in its impact on the immune system. Recent reviews have concentrated on diverse materials and their function in cancer therapy. In this review, we focus on the molecular mechanism of photothermal, photodynamic and sonodynamic cancer therapies and the connected role of cGAS-STING agonists in treating cancer. Full article

(This article belongs to the Special Issue Nanomaterials in Cancer Therapy: Synthesis, Mechanisms, and Applications)

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9 pages, 1030 KiB

Open AccessArticle

Synthesis of N-(3-Acyloxyacyl)glycines, Small Molecules with Potential Role in Gut Microbiome-Endocannabinoidome Communication

by Rosaria Villano and Vincenzo Di Marzo

Molecules 2024, 29(15), 3703; https://doi.org/10.3390/molecules29153703 - 5 Aug 2024

Viewed by 586

Abstract

The synthesis of some N-(3-acyloxyacyl)glycines, an interesting class of bioactive gut microbiota metabolites, is described. This procedure involves seven reaction steps using the commercially available Meldrum’s acid to obtain highly pure products, in normal or deuterated form. The key point of the [...] Read more.

The synthesis of some N-(3-acyloxyacyl)glycines, an interesting class of bioactive gut microbiota metabolites, is described. This procedure involves seven reaction steps using the commercially available Meldrum’s acid to obtain highly pure products, in normal or deuterated form. The key point of the synthetic strategy was the use of commendamide t-butyl ester as a synthetic intermediate, a choice that allowed the removal of the protecting group at the end of the synthetic procedure without degrading of the other ester bond present in the molecule. The developed synthetic sequence is particularly simple, uses readily available reagents and involves a limited number of purifications by chromatographic column, with a reduction in the volume of solvent and energy used. Full article

(This article belongs to the Section Organic Chemistry)

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14 pages, 2152 KiB

Open AccessArticle

Experimental and Modeling Study on Methane Hydrate Equilibrium Conditions in the Presence of Inorganic Salts

by Qiang Fu, Mingqiang Chen, Weixin Pang, Zhen Xu, Zengqi Liu, Huiyun Wen and Xin Lei

Molecules 2024, 29(15), 3702; https://doi.org/10.3390/molecules29153702 - 5 Aug 2024

Viewed by 486

Abstract

The aim of this study was to determine the influence of four inorganic salts, KCl, NaCl, KBr and NaBr, on the thermodynamic conditions of methane hydrate formation. In order to achieve this, the vapor–liquid water-hydrate (VL_WH) equilibrium conditions of methane (CH [...] Read more.

The aim of this study was to determine the influence of four inorganic salts, KCl, NaCl, KBr and NaBr, on the thermodynamic conditions of methane hydrate formation. In order to achieve this, the vapor–liquid water-hydrate (VL_WH) equilibrium conditions of methane (CH₄) hydrate were measured in the temperature range of 274.15 K–282.15 K by the isothermal pressure search method. The results demonstrated that, in comparison with deionized water, the four inorganic salts exhibited a significant thermodynamic inhibition on CH₄ hydrate. Furthermore, the inhibitory effect of Na⁺ on methane hydrate is more pronounced than that of K⁺, where there is no discernible difference between Cl⁻ and Br⁻. The dissociation enthalpy (

∆ H_{d i s s}

) of CH₄ hydrate in the four inorganic salt solutions is comparable to that of deionized water, indicating that the inorganic salt does not participate in the formation of hydrate crystals. The Chen–Guo hydrate model and N–NRTL–NRF activity model were employed to forecast the equilibrium conditions of CH₄ hydrate in electrolyte solution. The absolute relative deviation (AARD) between the predicted and experimental values were 1.24%, 1.08%, 1.18% and 1.21%, respectively. The model demonstrated satisfactory universality and accuracy. This study presents a novel approach to elucidating the mechanism and model prediction of inorganic salt inhibition of hydrate. Full article

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16 pages, 3164 KiB

Open AccessArticle

Synthesis and Evaluation of Chloride-Substituted Ramalin Derivatives for Alzheimer’s Disease Treatment

by Tai Kyoung Kim, Yongeun Cho, Jaewon Kim, Jeongmi Lee, Ju-Mi Hong, Heewon Cho, Jun-Sik Kim, Yeongyeong Lee, Kyung Hee Kim, Il-Chan Kim, Se Jong Han, Hyuncheol Oh, Dong-Gyu Jo and Joung Han Yim

Molecules 2024, 29(15), 3701; https://doi.org/10.3390/molecules29153701 - 5 Aug 2024

Viewed by 522

Abstract

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder marked by the accumulation of amyloid-beta plaques and hyperphosphorylated tau proteins, leading to cognitive decline and neuronal death. However, despite extensive research, there are still no effective treatments for this condition. In this study, a [...] Read more.

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder marked by the accumulation of amyloid-beta plaques and hyperphosphorylated tau proteins, leading to cognitive decline and neuronal death. However, despite extensive research, there are still no effective treatments for this condition. In this study, a series of chloride-substituted Ramalin derivatives is synthesized to optimize their antioxidant, anti-inflammatory, and their potential to target key pathological features of Alzheimer’s disease. The effect of the chloride position on these properties is investigated, specifically examining the potential of these derivatives to inhibit tau aggregation and beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1) activity. Our findings demonstrate that several derivatives, particularly RA-3Cl, RA-4Cl, RA-26Cl, RA-34Cl, and RA-35Cl, significantly inhibit tau aggregation with inhibition rates of approximately 50%. For BACE-1 inhibition, Ramalin and RA-4Cl also significantly decrease BACE-1 expression in N2a cells by 40% and 38%, respectively, while RA-23Cl and RA-24Cl showed inhibition rates of 30% and 35% in SH-SY5Y cells. These results suggest that chloride-substituted Ramalin derivatives possess promising multifunctional properties for AD treatment, warranting further investigation and optimization for clinical applications. Full article

(This article belongs to the Section Organic Chemistry)

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13 pages, 3706 KiB

Open AccessArticle

Signal-On Detection of Caspase-3 with Methylene Blue-Loaded Metal-Organic Frameworks as Signal Reporters

by Yaliang Huang, Jiaqiang Wang, Yirui Xu, Jiwen Zhang and Ning Xia

Molecules 2024, 29(15), 3700; https://doi.org/10.3390/molecules29153700 - 5 Aug 2024

Viewed by 434

Abstract

In this work, we report on an electrochemical method for the signal-on detection of caspase-3 and the evaluation of apoptosis based on the biotinylation reaction and the signal amplification of methylene blue (MB)-loaded metal–organic frameworks (MOFs). Zr-based UiO-66-NH₂ MOFs were used as [...] Read more.

In this work, we report on an electrochemical method for the signal-on detection of caspase-3 and the evaluation of apoptosis based on the biotinylation reaction and the signal amplification of methylene blue (MB)-loaded metal–organic frameworks (MOFs). Zr-based UiO-66-NH₂ MOFs were used as the nanocarriers to load electroactive MB molecules. Recombinant hexahistidine (His₆)-tagged streptavidin (rSA) was attached to the MOFs through the coordination interaction between the His₆ tag in rSA and the metal ions on the surface of the MOFs. The acetylated peptide substrate Ac-GDEVDGGGPPPPC was immobilized on the gold electrode. In the presence of caspase-3, the peptide was specifically cleaved, leading to the release of the Ac-GDEVD sequence. A N-terminal amine group was generated and then biotinylated in the presence of biotin-NHS. Based on the strong interaction between rSA and biotin, rSA@MOF@MB was captured by the biotinylated peptide-modified electrode, producing a significantly amplified electrochemical signal. Caspase-3 was sensitively determined with a linear range from 0.1 to 25 pg/mL and a limit of detection down to 0.04 pg/mL. Further, the active caspase-3 in apoptosis inducer-treated HeLa cells was further quantified by this method. The proposed signal-on biosensor is compatible with the complex biological samples and shows great potential for apoptosis-related diagnosis and the screening of caspase-targeting drugs. Full article

(This article belongs to the Special Issue Metal Organic Frameworks (MOFs) for Sensing Applications)

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19 pages, 6568 KiB

Open AccessArticle

Quantitative Analysis of Pb in Soil Using Laser-Induced Breakdown Spectroscopy Based on Signal Enhancement of Conductive Materials

by Shefeng Li, Qi Zheng, Xiaodan Liu, Peng Liu and Long Yu

Molecules 2024, 29(15), 3699; https://doi.org/10.3390/molecules29153699 - 5 Aug 2024

Viewed by 479

Abstract

Studying efficient and accurate soil heavy-metal detection technology is of great significance to establishing a modern system for monitoring soil pollution, early warning and risk assessment, which contributes to the continuous improvement of soil quality and the assurance of food safety. Laser-induced breakdown [...] Read more.

Studying efficient and accurate soil heavy-metal detection technology is of great significance to establishing a modern system for monitoring soil pollution, early warning and risk assessment, which contributes to the continuous improvement of soil quality and the assurance of food safety. Laser-induced breakdown spectroscopy (LIBS) is considered to be an emerging and effective tool for heavy-metal detection, compared with traditional detection technologies. Limited by the soil matrix effect, the LIBS signal of target elements for soil heavy-metal detection is prone to interference, thereby compromising the accuracy of quantitative detection. Thus, a series of signal-enhancement methods are investigated. This study aims to explore the effect of conductive materials of NaCl and graphite on the quantitative detection of lead (Pb) in soil using LIBS, seeking to find a reliable signal-enhancement method of LIBS for the determination of soil heavy-metal elements. The impact of the addition amount of NaCl and graphite on spectral intensity and parameters, including the signal-to-background ratio (SBR), signal-to-noise ratio (SNR), and relative standard deviation (RSD), were investigated, and the mechanism of signal enhancement by NaCl and graphite based on the analysis of the three-dimensional profile data of ablation craters and plasma parameters (plasmatemperature and electron density) were explored. Univariate and multivariate quantitative analysis models including partial least-squares regression (PLSR), least-squares support vector machine (LS-SVM), and extreme learning machine (ELM) were developed for the quantitative detection of Pb in soil with the optimal amount of NaCl and graphite, and the performance of the models was further compared. The PLSR model with the optimal amount of graphite obtained the best prediction performance, with an Rp that reached 0.994. In addition, among the three spectral lines of Pb, the univariate model of Pb I 405.78 nm showed the best prediction performance, with an Rp of 0.984 and the lowest LOD of 26.142 mg/kg. The overall results indicated that the LIBS signal-enhancement method based on conductive materials combined with appropriate chemometric methods could be a potential tool for the accurate quantitative detection of Pb in soil and could provide a reference for environmental monitoring. Full article

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17 pages, 20487 KiB

Open AccessArticle

The Impact of Cyclodextrins on the Physiology of Candida boidinii: Exploring New Opportunities in the Cyclodextrin Application

by Rita Márton, Márk Margl, Lilla Kinga Tóth, Éva Fenyvesi, Lajos Szente and Mónika Molnár

Molecules 2024, 29(15), 3698; https://doi.org/10.3390/molecules29153698 - 5 Aug 2024

Viewed by 542

Abstract

Cyclodextrins, commonly used as excipients in antifungal formulations to improve the physicochemical properties and availability of the host molecules, have not been systematically studied for their effects and bioactivity without a complex active substance. This paper evaluates the effects of various cyclodextrins on [...] Read more.

Cyclodextrins, commonly used as excipients in antifungal formulations to improve the physicochemical properties and availability of the host molecules, have not been systematically studied for their effects and bioactivity without a complex active substance. This paper evaluates the effects of various cyclodextrins on the physiology of the test organism Candida boidinii. The research examines their impact on yeast growth, viability, biofilm formation and morphological changes. Native ACD, BCD, randomly methylated α- and β-CD and quaternary ammonium α-CD and β-CD were investigated in the 0.5–12.5 mM concentration range in both static and dynamic systems. The study revealed that certain cyclodextrins exhibited notable antifungal effects (up to ~69%) in dynamic systems; however, the biofilm formation was enhanced in static systems. The magnitude of these effects was influenced by several variables, including the size of the internal cavity, the concentration and structure of the cyclodextrins, and the contact time. Furthermore, the study found that CDs exhibited distinct effects in both static and dynamic systems, potentially related to their tendency to form aggregates. The findings suggest that cyclodextrins may have the potential to act as antifungal agents or growth promoters, depending on their structure and surrounding environments. Full article

(This article belongs to the Special Issue Synthesis and Molecular Recognition of Macrocyclic Compounds, 2nd Edition)

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12 pages, 2613 KiB

Open AccessArticle

Sustainable Epoxy Composites with UV Resistance Based on New Kraft Lignin Coatings

by Rubén Seoane-Rivero, Patricia Ares-Elejoste, Koldo Gondra, Sara Amini, Pedro-Luis de Hoyos and Maria Gonzalez-Alriols

Molecules 2024, 29(15), 3697; https://doi.org/10.3390/molecules29153697 - 5 Aug 2024

Viewed by 461

Abstract

Currently, the composite industry is focusing on more environmentally friendly resources in order to generate a new range of biobased materials. In this manuscript, we present a new work using lignocellulosic wastes from the paper industry to incorporate into biobased epoxy systems. The [...] Read more.

Currently, the composite industry is focusing on more environmentally friendly resources in order to generate a new range of biobased materials. In this manuscript, we present a new work using lignocellulosic wastes from the paper industry to incorporate into biobased epoxy systems. The manufactured materials were composed of kraft lignin, glass fiber, and a sustainable epoxy system, obtaining a 40% biobased content. Using a vacuum infusion process, we fabricated the composites and analyzed their mechanical and UV resistance properties. The findings reveal a significant correlation between the lignin content and flexural modulus and strength, showing an increase of 69% in the flexural modulus and 134% in the flexural strength with the presence of 5% of lignin content. Moreover, it is necessary to highlight that the presence of synthesized lignin inhibits the UV degradation of the biobased epoxy coating. We propose that the use of lignocellulosic-based wastes could improve the mechanical properties and generate UV resistance in the composite materials. Full article

(This article belongs to the Special Issue Epoxy Resin Synthesis, Performance and Application Research)

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11 pages, 18667 KiB

Open AccessArticle

Corrosion and Interfacial Contact Resistance of NiTi Alloy as a Promising Bipolar Plate for PEMFC

by Yingping Li, Xiaofen Wang, Yuanyuan Li, Zhuo He, Guohong Zhang, Zhen Wang, Shaohua Wang, Fei Hu and Qiongyu Zhou

Molecules 2024, 29(15), 3696; https://doi.org/10.3390/molecules29153696 - 5 Aug 2024

Viewed by 568

Abstract

Titanium (Ti) is generally considered as an ideal bipolar plate (BPP) material because of its excellent corrosion resistance, good machinability and lightweight nature. However, the easy-passivation property, which leads to increased interfacial contact resistance (ICR) and subsequently decreased cell performance, limits its large-scale [...] Read more.

Titanium (Ti) is generally considered as an ideal bipolar plate (BPP) material because of its excellent corrosion resistance, good machinability and lightweight nature. However, the easy-passivation property, which leads to increased interfacial contact resistance (ICR) and subsequently decreased cell performance, limits its large-scale commercial application in proton exchange membrane fuel cells (PEMFCs). In this paper, we proposed a NiTi alloy prepared by suction casting as a promising bipolar plate for PEMFCs. This NiTi alloy exhibits significantly decreased ICR values (16.8 mΩ cm² at 1.4 MPa) compared with pure Ti (88.6 mΩ cm² at 1.4 MPa), along with enhanced corrosion resistance compared with pure nickel (Ni). The superior corrosion resistance of NiTi alloy is accredited to the nobler open circuit potential and corrosion potential, coupled with low corrosion current densities and passive current densities. The improved ICR can be interpreted by the existence of high-proportioned metallic Ni in the passive film, which contributes to the reduced capacitance characteristic of the passive film (compared with Ti) and enhances charge conduction. This work provides a feasible option to ameliorate BPP material that may have desirable corrosion resistance and ICR. Full article

(This article belongs to the Special Issue Electroanalysis of Biochemistry and Material Chemistry)

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13 pages, 5211 KiB

Open AccessArticle

Thermodynamic Studies of Complexes in Cu(II)/Uridine-5′-Diphosphoglucuronic Acid System

by Klaudia Stachowiak, Michal Zabiszak, Jakub Grajewski, Anna Teubert, Anna Bajek and Renata Jastrzab

Molecules 2024, 29(15), 3695; https://doi.org/10.3390/molecules29153695 - 4 Aug 2024

Viewed by 747

Abstract

A binary system of uridine-5′-diphosphoglucuronic acid with copper (II) ions was studied. Potentiometric studies in aqueous solutions using computer data analysis were carried out. The pH of dominance, the overall stability constants (logβ), and the equilibrium constants of the formation reaction [...] Read more.

A binary system of uridine-5′-diphosphoglucuronic acid with copper (II) ions was studied. Potentiometric studies in aqueous solutions using computer data analysis were carried out. The pH of dominance, the overall stability constants (logβ), and the equilibrium constants of the formation reaction (logK_e) were determined for each complex compound formed in the studied system. Spectroscopic studies were carried out to determine the mode of coordination in the compounds studied. Cytotoxicity and metabolic activity tests of the compounds obtained showed an increase in the biological activity of the complexes tested against the free ligand. The current research may contribute to the knowledge of complex compounds of biomolecules found in the human body and may also contribute to the characterization of a group of complex compounds with potential anticancer properties. Full article

(This article belongs to the Special Issue Synthesis, Structure, Molecular Modeling, and Bioactivity of Metal Complexes)

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59 pages, 2461 KiB

Open AccessReview

From Classical to Alternative Pathways of 2-Arachidonoylglycerol Synthesis: AlterAGs at the Crossroad of Endocannabinoid and Lysophospholipid Signaling

by Fabienne Briand-Mésange, Isabelle Gennero, Juliette Salles, Stéphanie Trudel, Lionel Dahan, Jérôme Ausseil, Bernard Payrastre, Jean-Pierre Salles and Hugues Chap

Molecules 2024, 29(15), 3694; https://doi.org/10.3390/molecules29153694 - 4 Aug 2024

Viewed by 1239

Abstract

2-arachidonoylglycerol (2-AG) is the most abundant endocannabinoid (EC), acting as a full agonist at both CB1 and CB2 cannabinoid receptors. It is synthesized on demand in postsynaptic membranes through the sequential action of phosphoinositide-specific phospholipase Cβ1 (PLCβ1) and diacylglycerol lipase α (DAGLα), contributing [...] Read more.

2-arachidonoylglycerol (2-AG) is the most abundant endocannabinoid (EC), acting as a full agonist at both CB1 and CB2 cannabinoid receptors. It is synthesized on demand in postsynaptic membranes through the sequential action of phosphoinositide-specific phospholipase Cβ1 (PLCβ1) and diacylglycerol lipase α (DAGLα), contributing to retrograde signaling upon interaction with presynaptic CB1. However, 2-AG production might also involve various combinations of PLC and DAGL isoforms, as well as additional intracellular pathways implying other enzymes and substrates. Three other alternative pathways of 2-AG synthesis rest on the extracellular cleavage of 2-arachidonoyl-lysophospholipids by three different hydrolases: glycerophosphodiesterase 3 (GDE3), lipid phosphate phosphatases (LPPs), and two members of ecto-nucleotide pyrophosphatase/phosphodiesterases (ENPP6–7). We propose the names of AlterAG-1, -2, and -3 for three pathways sharing an ectocellular localization, allowing them to convert extracellular lysophospholipid mediators into 2-AG, thus inducing typical signaling switches between various G-protein-coupled receptors (GPCRs). This implies the critical importance of the regioisomerism of both lysophospholipid (LPLs) and 2-AG, which is the object of deep analysis within this review. The precise functional roles of AlterAGs are still poorly understood and will require gene invalidation approaches, knowing that both 2-AG and its related lysophospholipids are involved in numerous aspects of physiology and pathology, including cancer, inflammation, immune defenses, obesity, bone development, neurodegeneration, or psychiatric disorders. Full article

(This article belongs to the Special Issue Bioactive Lipids in Inflammatory Diseases)

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18 pages, 2492 KiB

Open AccessArticle

Product Selectivity Control in the Brønsted Acid-Mediated Reactions with 2-Alkynylanilines

by Valerio Morlacci, Massimiliano Aschi, Marco Chiarini, Caterina Momoli, Laura Palombi and Antonio Arcadi

Molecules 2024, 29(15), 3693; https://doi.org/10.3390/molecules29153693 - 4 Aug 2024

Viewed by 512

Abstract

Brønsted acid-catalysed/mediated reactions of the 2-alkynylanilines are reported. While metal-catalysed reactions of these valuable building blocks have led to the establishment of robust protocols for the selective, diverse-oriented syntheses of significant heterocyclic derivatives, we here demonstrate the practical advantages of an alternative methodology [...] Read more.

Brønsted acid-catalysed/mediated reactions of the 2-alkynylanilines are reported. While metal-catalysed reactions of these valuable building blocks have led to the establishment of robust protocols for the selective, diverse-oriented syntheses of significant heterocyclic derivatives, we here demonstrate the practical advantages of an alternative methodology under metal-free conditions. Our investigation into the key factors influencing the product selectivity in Brønsted acid-catalysed/mediated reactions of 2-alkynylanilines reveals that different reaction pathways can be directed towards the formation of diverse valuable products by simply choosing appropriate reaction conditions. The origins of chemo- and regioselectivity switching have been explored through Density Functional Theory (DFT) calculations. Full article

(This article belongs to the Special Issue Advances in Heterocyclic Synthesis)

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13 pages, 4199 KiB

Open AccessArticle

Utilization of Lead Nitrate to Enhance the Impact of Hydroxamic Acids on the Hydrophobic Aggregation and Flotation Behavior of Cassiterite

by Saizhen Jin, Xiaobo Liu, Yun Feng, Yanfei Chen, Mengtao Wang and Qingfei Xiao

Molecules 2024, 29(15), 3692; https://doi.org/10.3390/molecules29153692 - 4 Aug 2024

Viewed by 536

Abstract

Lead nitrate (LN) is frequently employed as an activator in the flotation of cassiterite using hydroxamic acids as the collectors. This study investigated the effect of LN on the hydrophobic aggregation of cassiterite when benzohydroxamic acid (BHA), hexyl hydroxamate (HHA), and octyl hydroxamate [...] Read more.

Lead nitrate (LN) is frequently employed as an activator in the flotation of cassiterite using hydroxamic acids as the collectors. This study investigated the effect of LN on the hydrophobic aggregation of cassiterite when benzohydroxamic acid (BHA), hexyl hydroxamate (HHA), and octyl hydroxamate (OHA) were used as the collectors through micro-flotation, focused beam reflectance measurement (FBRM) and a particle video microscope (PVM), zeta potential, and the extended DLVO theory. Micro-flotation tests confirmed that LN activated the flotation of cassiterite using the hydroxamic acids as collectors. Focused beam reflectance measurement (FBRM) and a particle video microscope (PVM) were used to capture in situ data on the changes in size distribution and morphology of cassiterite aggregates during stirring. The FBRM and PVM image results indicated that the addition of LN could promote the formation of hydrophobic aggregates of fine cassiterite, when BHA or HHA was used as the collector, and reduce the dosage of OHA needed to induce the formation of hydrophobic aggregates of cassiterite. The extended DLVO theory interaction energies indicated that the presence of LN could decrease the electrostatic interaction energies (V_edl) and increase the hydrophobic interaction energies (V_hy) between cassiterite particles, resulting in the disappearance of the high energy barriers that existed between the particles in the absence of LN. Thus, cassiterite particles could aggregate in the presence of LN when BHA, HHA, or a low concentration of OHA was used as the collector. Full article

(This article belongs to the Special Issue Molecular Structure of Minerals)

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28 pages, 9422 KiB

Open AccessReview

Comprehensive Review of Synthesis, Optical Properties and Applications of Heteroarylphosphonates and Their Derivatives

by Krzysztof Owsianik, Adrian Romaniuk, Marika Turek and Piotr Bałczewski

Molecules 2024, 29(15), 3691; https://doi.org/10.3390/molecules29153691 - 4 Aug 2024

Viewed by 848

Abstract

This review focuses on optical properties of compounds in which at least one phosphonate group is directly attached to a heteroaromatic ring. Additionally, the synthesis and other applications of these compounds are addressed in this work. The influence of the phosphonate substituent on [...] Read more.

This review focuses on optical properties of compounds in which at least one phosphonate group is directly attached to a heteroaromatic ring. Additionally, the synthesis and other applications of these compounds are addressed in this work. The influence of the phosphonate substituent on the properties of the described compounds is discussed and compared with other non-phosphorus substituents, with particular attention given to photophysical properties, such as UV-Vis absorption and emission, fluorescence quantum yield and fluorescence lifetime. Considering the presence of heteroatom, the collected material was divided into two parts, and a review of the literature of the last thirty years on heteroaryl phosphonates containing sulfur and nitrogen atoms in the aromatic ring was conducted. Full article

(This article belongs to the Special Issue Organophosphorus Chemistry: A New Perspective, 2nd Edition)

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16 pages, 3519 KiB

Open AccessArticle

Adsorptive–Photocatalytic Composites of α-Ferrous Oxalate Supported on Activated Carbon for the Removal of Phenol under Visible Irradiation

by Salomé Galeas, Víctor H. Guerrero, Patricia I. Pontón, Carla S. Valdivieso-Ramírez, Paul Vargas-Jentzsch, Paola Zárate and Vincent Goetz

Molecules 2024, 29(15), 3690; https://doi.org/10.3390/molecules29153690 - 4 Aug 2024

Viewed by 613

Abstract

Adsorptive–photocatalytic composites based on activated carbon (AC) and α-ferrous oxalate dihydrate (α-FOD) were synthesized by an original two-step method and subsequently used for the removal of phenol from aqueous solutions. To obtain the composites, ferrotitaniferous black mineral sands (0.6FeTiO₃·0.4Fe₂O [...] Read more.

Adsorptive–photocatalytic composites based on activated carbon (AC) and α-ferrous oxalate dihydrate (α-FOD) were synthesized by an original two-step method and subsequently used for the removal of phenol from aqueous solutions. To obtain the composites, ferrotitaniferous black mineral sands (0.6FeTiO₃·0.4Fe₂O₃) were first dissolved in an oxalic acid solution at ambient pressure, and further treated under hydrothermal conditions to precipitate α-FOD on the AC surface. The ratio of oxalic acid to the mineral sand precursor was tuned to obtain composites with 8.3 and 42.7 wt.% of α-FOD on the AC surface. These materials were characterized by X-ray powder diffraction, scanning electron microscopy, and the nitrogen adsorption–desorption method. The phenol removal efficiency of the composites was determined during 24 h of adsorption under dark conditions, followed by 24 h of adsorption–photocatalysis under visible light irradiation. AC/α-FOD composites with 8.3 and 42.7 wt.% of α-FOD adsorbed 60% and 51% of phenol in 24 h and reached a 90% and 96% removal efficiency after 12 h of irradiation, respectively. Given its higher photocatalytic response, the 42.7 wt.% α-FOD composite was also tested during successive cycles of adsorption and adsorption–photocatalysis. This composite exhibited a reasonable level of cyclability (~99% removal after four alternated dark/irradiated cycles of 24 h and ~68% removal after three simultaneous adsorption–photocatalysis cycles of 24 h). The promising performance of the as-prepared composites opens several opportunities for their application in the effective removal of organic micropollutants from water. Full article

(This article belongs to the Special Issue Heterogeneous Catalysis for Sustainability and Carbon-Neutrality)

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13 pages, 1304 KiB

Open AccessArticle

Substituent Effects in the Photophysical and Electrochemical Properties of Meso-Tetraphenylporphyrin Derivatives

by Alexandra Cruz Millheim, Enric Ponzano and Albert Moyano

Molecules 2024, 29(15), 3689; https://doi.org/10.3390/molecules29153689 - 4 Aug 2024

Viewed by 464

Abstract

Porphyrins were identified some years ago as a promising, easily accessible, and tunable class of organic photoredox catalysts, but a systematic study on the effect of the electronic nature and of the position of the substituents on both the ground-state and the excited-state [...] Read more.

Porphyrins were identified some years ago as a promising, easily accessible, and tunable class of organic photoredox catalysts, but a systematic study on the effect of the electronic nature and of the position of the substituents on both the ground-state and the excited-state redox potentials of these compounds is still lacking. We prepared a set of known functionalized porphyrin derivatives containing different substituents either in one of the meso positions or at a β-pyrrole carbon, and we determined their ground- and (singlet) excited-state redox potentials. We found that while the estimated singlet excited-state energies are essentially unaffected by the introduction of substituents, the redox potentials (both in the ground- and in the singlet excited-state) depend on the electron-withdrawing or electron-donating nature of the substituents. Thus, the presence of groups with electron-withdrawing resonance effects results in an enhancement of the reduction facility of the photocatalyst, both in the ground and in the excited state. We next prepared a second set of four previously unknown meso-substituted porphyrins, having a benzoyl group at different positions. The reduction facility of the porphyrin increases with the proximity of the substituent to the porphine core, reaching a maximum when the benzoyl substituent is introduced at a meso position. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application, 2nd Edition)

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14 pages, 5206 KiB

Open AccessArticle

Carbonized Ganoderma Lucidum/V₂O₃ Composites as a Superior Cathode for High-Performance Aqueous Zinc-Ion Batteries

by Guilin Zeng, Zhengda Li, Shaohua Jiang and Wei Zhou

Molecules 2024, 29(15), 3688; https://doi.org/10.3390/molecules29153688 - 4 Aug 2024

Viewed by 478

Abstract

In response to the suboptimal electrochemical performance of low-valence vanadium oxides, Ganoderma lucidum biomass-derived carbon@V₂O₃ (V₂O₃@CGL) composites were prepared by evaporative self-assembly technology and high-temperature calcination. In the prepared composites, V₂O₃ effectively encapsulates [...] Read more.

In response to the suboptimal electrochemical performance of low-valence vanadium oxides, Ganoderma lucidum biomass-derived carbon@V₂O₃ (V₂O₃@CGL) composites were prepared by evaporative self-assembly technology and high-temperature calcination. In the prepared composites, V₂O₃ effectively encapsulates CGL, serving as a support for V₂O₃ and enhancing electrical conductivity and structural stability. This results in improved overall performance for the composites. They revealed satisfactory electrochemical properties when assembled in aqueous zinc-ion batteries (AZIBs). The preliminary discharge specific capacity of the V₂O₃@CGL-2 (VOCG-2) composite electrode reached 407.87 mAh g⁻¹ at 0.05 A g⁻¹. After 1000 cycles, the capacity retention is 93.69% at 3 A g⁻¹. This research underscores the feasibility of employing V₂O₃ and abundantly available biomass for high-performance AZIB cathodes. Full article

(This article belongs to the Special Issue Novel Electrode Materials for Rechargeable Batteries, 2nd Edition)

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17 pages, 1623 KiB

Open AccessReview

Dynamic and Static Regulation of Nicotinamide Adenine Dinucleotide Phosphate: Strategies, Challenges, and Future Directions in Metabolic Engineering

by Nana Ding, Zenan Yuan, Lei Sun and Lianghong Yin

Molecules 2024, 29(15), 3687; https://doi.org/10.3390/molecules29153687 - 3 Aug 2024

Viewed by 724

Abstract

Reduced nicotinamide adenine dinucleotide phosphate (NADPH) is a crucial cofactor in metabolic networks. The efficient regeneration of NADPH is one of the limiting factors for productivity in biotransformation processes. To date, many metabolic engineering tools and static regulation strategies have been developed to [...] Read more.

Reduced nicotinamide adenine dinucleotide phosphate (NADPH) is a crucial cofactor in metabolic networks. The efficient regeneration of NADPH is one of the limiting factors for productivity in biotransformation processes. To date, many metabolic engineering tools and static regulation strategies have been developed to regulate NADPH regeneration. However, traditional static regulation methods often lead to the NADPH/NADP⁺ imbalance, causing disruptions in cell growth and production. These methods also fail to provide real-time monitoring of intracellular NADP(H) or NADPH/NADP⁺ levels. In recent years, various biosensors have been developed for the detection, monitoring, and dynamic regulate of the intracellular NADP(H) levels or the NADPH/NADP⁺ balance. These NADPH-related biosensors are mainly used in the cofactor engineering of bacteria, yeast, and mammalian cells. This review analyzes and summarizes the NADPH metabolic regulation strategies from both static and dynamic perspectives, highlighting current challenges and potential solutions, and discusses future directions for the advanced regulation of the NADPH/NADP⁺ balance. Full article

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17 pages, 15484 KiB

Open AccessArticle

Competitive Adsorptive Mechanism of H₂/N₂ in LTA/FAU Zeolites by Molecular Simulations and Experiments

by Zixu Dong, Zhilu Wang, Lina Zhang, Qiang Fu and Ming Wang

Molecules 2024, 29(15), 3686; https://doi.org/10.3390/molecules29153686 - 3 Aug 2024

Viewed by 705

Abstract

For industrial tail gas to be converted into high-purity hydrogen, the H₂-N₂ mixture needs to be separated efficiently. This work examined the adsorption characteristics and competitive mechanisms of H₂ and N₂ on LTA- and FAU-type zeolites, at 77 [...] Read more.

For industrial tail gas to be converted into high-purity hydrogen, the H₂-N₂ mixture needs to be separated efficiently. This work examined the adsorption characteristics and competitive mechanisms of H₂ and N₂ on LTA- and FAU-type zeolites, at 77 K, 298 K, and 0.1–10 bar by thoroughly analyzing results of adsorption capacity experiments and molecular simulations. In the Grand Canonical Monte Carlo (GCMC) simulations, the force field causing a molecular dipole of H₂ and the polarization force field of N₂ are first applied. The accuracy of the force field was experimentally verified. The findings indicate that N₂ and H₂ loading on Ca-FAU (Ca-LTA) are higher than Na-FAU (Na-LTA). On NaX at 77 K, the highest adsorption selectivity (N₂/H₂) is observed; on NaA at 298 K, it is the opposite. The GCMC data findings demonstrate that H₂ and N₂ have remarkably similar adsorption sites, with framework oxygen atoms and non-framework cations serving as the main adsorption sites for adsorbate molecules. Furthermore, the rate at which H₂ diffuses is higher than that of N₂. The study of redistribution charge before and after adsorption demonstrated that N₂ has a greater affinity for the framework oxygen atoms than H₂. This study provides a molecular theoretical foundation for the adsorption behavior of H₂-N₂ mixture in zeolites. Full article

(This article belongs to the Special Issue Application of Computer Simulation in Materials Science of Molecules, 2nd Edition)

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39 pages, 18396 KiB

Open AccessReview

Asymmetric Synthesis and Applications of Chiral Organoselenium Compounds: A Review

by Yanyu Jian, Thishana Singh, Pher G. Andersson and Taigang Zhou

Molecules 2024, 29(15), 3685; https://doi.org/10.3390/molecules29153685 - 3 Aug 2024

Viewed by 1067

Abstract

The synthesis and application of organoselenium compounds have developed rapidly, and chiral organoselenium compounds have become an important intermediate in the field of medicine, materials, organic synthesis. The strategy of developing a green economy is still a challenge in the synthesis of chiral [...] Read more.

The synthesis and application of organoselenium compounds have developed rapidly, and chiral organoselenium compounds have become an important intermediate in the field of medicine, materials, organic synthesis. The strategy of developing a green economy is still a challenge in the synthesis of chiral organoselenium compounds with enantioselective properties. This review covers in detail the synthesis of chiral organoselenium compounds from 1979 to 2024 and their application in the fields of asymmetric synthesis and catalysis. Full article

(This article belongs to the Section Organic Chemistry)

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