Journal Description
Molecules
Molecules
is the leading international, peer-reviewed, open access journal of chemistry. Molecules is published semimonthly online by MDPI. The International Society of Nucleosides, Nucleotides & Nucleic Acids (IS3NA), the Spanish Society of Medicinal Chemistry (SEQT) and the International Society of Heterocyclic Chemistry (ISHC) are affiliated with Molecules and their members receive a discount on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), PubMed, MEDLINE, PMC, Reaxys, CaPlus / SciFinder, MarinLit, AGRIS, and other databases.
- Journal Rank: JCR - Q2 (Chemistry, Multidisciplinary) / CiteScore - Q1 (Chemistry (miscellaneous))
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 14.6 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Sections: published in 26 topical sections.
- Testimonials: See what our editors and authors say about Molecules.
- Companion journals for Molecules include: Foundations and Photochem.
Impact Factor:
4.6 (2022);
5-Year Impact Factor:
4.9 (2022)
Latest Articles
Photocatalytic Degradation of Naproxen: Intermediates and Total Reaction Mechanism
Molecules 2024, 29(11), 2583; https://doi.org/10.3390/molecules29112583 (registering DOI) - 30 May 2024
Abstract
Photochemical and photocatalytic oxidation of naproxen (NPX) with UV-A light and commercial TiO2 under constant flow of oxygen have been investigated. Adsorption experiments indicated that 90% of the solute remained in the solution. Combined chemical analysis of samples on the photochemical degradation
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Photochemical and photocatalytic oxidation of naproxen (NPX) with UV-A light and commercial TiO2 under constant flow of oxygen have been investigated. Adsorption experiments indicated that 90% of the solute remained in the solution. Combined chemical analysis of samples on the photochemical degradation indicated that NPX in an aqueous solution (20 ppm) is efficiently transformed into other species but only 18% of the reactant is mineralized into CO2 and water after three hours of reaction. Performing the photocatalytic oxidation in the presence of TiO2, more than 80 % of the organic compounds are mineralized by reactive oxidation species (ROS) within four hours of reaction. Analysis of reaction mixtures by a combination of analytical techniques indicated that naproxen is transformed into several aromatic naphthalene derivatives. These latter compounds are eventually transformed into polyhydroxylated aromatic compounds that are strongly adsorbed onto the TiO2 surface and are quickly oxidized into low-molecular-weight acids by an electron transfer mechanism. Based on this and previous studies on NPX photocatalytic oxidation, a unified and complete degradation mechanism is presented.
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(This article belongs to the Special Issue Promising Catalytic Materials for Energy and Environmental Applications)
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Open AccessArticle
The Theoretical Calculation of the Cu Isotope Fractionation Effect in Solution/Hydrothermal Solution Systems
by
Jixi Zhang
Molecules 2024, 29(11), 2582; https://doi.org/10.3390/molecules29112582 (registering DOI) - 30 May 2024
Abstract
Abstract: Copper (Cu) is an important transition metal, and its isotopes have important applications in geology, environmental science, soil science, and other fields. Cu isotope fractionation can occur in many natural processes. However, the mechanism of Cu isotope fractionation in solution/hydrothermal solution systems
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Abstract: Copper (Cu) is an important transition metal, and its isotopes have important applications in geology, environmental science, soil science, and other fields. Cu isotope fractionation can occur in many natural processes. However, the mechanism of Cu isotope fractionation in solution/hydrothermal solution systems is not very clear. In this study, the fractionation effects of complexes of Cu(I) and Cu(II) in solution/hydrothermal solution systems were systematically studied by means of an ab initio method based on first principles. In the simulation of an aqueous solution system, the theoretical treatment method used is the “water-droplet” method. The results show that the heavy Cu isotope (65Cu) enrichment capacity of the Cu-bearing complex solutions is greatly affected by the ligand types both for Cu(I) and Cu(II). For Cu(I) complex solutions, the heavy Cu isotope enrichment sequence is [Cu(HS)2]−·(H2O)42 > [Cu(HS)(H2O)]·(H2O)42 ≈ [Cu(HS)(H2S)]·(H2O)42 > [CuCl]·(H2O)42 > [CuCl2]−·(H2O)42 > [CuCl3]2−·(H2O)42. For the aqueous solutions of Cu(II) with an inorganic ligand (such as H2O, OH−, NO3−, SO42− and CN−), the order of heavy Cu isotope enrichment is as follows: [Cu(H2O)6]2+·(H2O)42 > [Cu(NO3)2]·(H2O)42 > [Cu(OH)2]·(H2O)42 > [CuSO4(H2O)3]·(H2O)42 > [CuNO3(H2O)4]+·(H2O)42 > [CuCN]+·(H2O)42. For the Cu(II) complex solutions with a halogen as ligands, the change order of 1000lnβ is [CuCl]+·(H2O)42 > [CuCl2]·(H2O)42 > [CuBr2]·(H2O)42 > [CuCl3]−·(H2O)42. The sequence of 1000lnβ for Cu(II) organic complex aqueous solutions is [Cu(HOC6H4COO)]+·(H2O)42 > [Cu(CH3CH2COO)]+·(H2O)42 > [Cu(COOHCOO)]+·(H2O)42. The calculation also found that for Cu(I) complex aqueous solutions, the difference in Cu isotope fractionation parameters (1000lnβ) between [CuCl2]−·(H2O)42 and [Cu(HS)2]−·(H2O)42 is relatively large. At 100 °C, the 1000lnβ of the two species are 1.14 and 1.55 (‰), respectively. The difference between the two could be reached up to 0.41 (‰). The Cu isotope fractionation parameter obtained with the “water droplet” method is also very different from the results of previous studies, which indicate that the Cu isotope fractionation behavior of the two is similar. At the same time, the exciting discovery is that the enrichment capacity of heavy Cu isotopes is significantly different between Cu(I) complex aqueous solutions and Cu(II) complex aqueous solutions. At 100 °C, the 1000lnβ of 6 Cu(I) complex aqueous solutions and 13 Cu(II) complex aqueous solutions ranged from 0.90 to 1.55 and 2.24 to 3.25(‰), respectively. It also shows that the REDOX reaction has a significant effect on the Cu isotope fractionation, especially in ore-forming fluids. Therefore, the ligand type is a factor that cannot be ignored when considering the mechanism of Cu isotope fractionation in solution/hydrothermal solution systems. Whether the solvation effect of an aqueous solution is considered or not has a great influence on the numerical values of the final Cu isotope fractionation factors. Hence, the solvation effect of an aqueous solution is an essential determinant in the theoretical calculation of the Cu isotope fractionation factors for Cu-bearing complex solutions.
Full article
(This article belongs to the Section Computational and Theoretical Chemistry)
Open AccessArticle
Structure Characterization and Dye Adsorption Properties of Modified Fiber from Wheat Bran
by
Wenbin Quan, Juan Wang, Jihong Huang and Dale Zhang
Molecules 2024, 29(11), 2581; https://doi.org/10.3390/molecules29112581 (registering DOI) - 30 May 2024
Abstract
The fibers from four wheat varieties (FT, XW 26, XW 45, and KW 1701) were selected and chemically modified with NaOH, epichlorohydrin, and dimethylamine to improve the adsorption capacity for anionic dye. The structure of the fibers with or without modification was characterized
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The fibers from four wheat varieties (FT, XW 26, XW 45, and KW 1701) were selected and chemically modified with NaOH, epichlorohydrin, and dimethylamine to improve the adsorption capacity for anionic dye. The structure of the fibers with or without modification was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectrometry. The modified products were studied from the aspects of adsorption capacities, adsorption kinetics, and thermodynamics to provide a reference for the utilization of wheat bran. By SEM, more porous and irregular structures were found on the modified fibers. The XRD results showed that the crystals from the original fibers were destroyed in the modification process. The changes in fibers’ infrared spectra before and after modification suggested that quaternary ammonium salts were probably formed in the modification process. The maximum adsorption capacity of wheat bran fibers for Congo red within 120 min was 20 mg/g for the unmodified fiber (XW 26) and 93.46 mg/g for the modified one (XW 45). The adsorption kinetics of Congo red by modified wheat bran fiber was in accord with the pseudo-second-order kinetic model at 40 °C, 50 °C, and 60 °C, indicating that the adsorption process might be mainly dominated by chemisorption. The adsorption was more consistent with the Langmuir isothermal adsorption model, implying that this process was monolayer adsorption. The thermodynamic parameters suggested that the adsorption occurred spontaneously, and the temperature increase was favorable to the adsorption. As mentioned above, this study proved that the wheat bran fiber could possess good adsorption capacities for anion dye after chemical modification.
Full article
(This article belongs to the Special Issue Innovative Adsorbents for Pollutant Removal: An Overview of Current Research)
Open AccessArticle
Solid State and Solution Structures of Lanthanide Nitrate Complexes of Tris-(1-napthylphosphine Oxide)
by
Simon J. Coles, Laura J. McCormick McPherson, Andrew W. G. Platt and Kuldip Singh
Molecules 2024, 29(11), 2580; https://doi.org/10.3390/molecules29112580 - 30 May 2024
Abstract
Coordination complexes of lanthanide metals with tris-1-naphthylphosphine oxide (Nap3PO, L) have not been previously reported in the literature. We describe here the formation of lanthanide(III) nitrate complexes Ln(NO3)3L4 (Ln = Eu to Lu) and the structures
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Coordination complexes of lanthanide metals with tris-1-naphthylphosphine oxide (Nap3PO, L) have not been previously reported in the literature. We describe here the formation of lanthanide(III) nitrate complexes Ln(NO3)3L4 (Ln = Eu to Lu) and the structures of [Ln(NO3)3L2]·2L (Ln = Eu, Dy, Ho, Er) and L. The core structure of the complexes is an eight-coordinate [Ln(NO3)3L2] with the third and fourth ligands H-bonded via their oxygen atoms to one of the naphthyl rings. The structures are compared with those of the analogous complexes of triphenylphosphine oxide and show that the Ln-O(P) bond in the Nap3PO complexes is slightly longer than expected on the basis of differences in coordination numbers. The reaction solutions, investigated by 31P and 13C NMR spectroscopy in CD3CN, show that coordination of L occurs across the lanthanide series, even though complexes can only be isolated from Eu onwards. Analysis of the 31P NMR paramagnetic shifts shows that there is a break in the solution structures with a difference between the lighter lanthanides (La–Eu) and heavier metals (Tb–Lu) which implies a minor difference in structures. The isolated complexes are very poorly soluble, but in CDCl3, NMR measurements show dissociation into [Ln(NO3)3L2] and 2L occurs.
Full article
(This article belongs to the Special Issue Inorganic Chemistry in Europe)
Open AccessArticle
Structural Analysis of the Large Stokes Shift Red Fluorescent Protein tKeima
by
Ki Hyun Nam and Yongbin Xu
Molecules 2024, 29(11), 2579; https://doi.org/10.3390/molecules29112579 - 30 May 2024
Abstract
The Keima family comprises large Stokes shift fluorescent proteins that are useful for dual-color fluorescence cross-correlation spectroscopy and multicolor imaging. The tKeima is a tetrameric large Stokes shift fluorescent protein and serves as the ancestor fluorescent protein for both dKeima and mKeima. The
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The Keima family comprises large Stokes shift fluorescent proteins that are useful for dual-color fluorescence cross-correlation spectroscopy and multicolor imaging. The tKeima is a tetrameric large Stokes shift fluorescent protein and serves as the ancestor fluorescent protein for both dKeima and mKeima. The spectroscopic properties of tKeima have been previously reported; however, its structural basis and molecular properties have not yet been elucidated. In this study, we present the crystallographic results of the large Stokes shift fluorescent protein tKeima. The purified tKeima protein spontaneously crystallized after purification without further crystallization. The crystal structure of tKeima was determined at 3.0 Å resolution, revealing a β-barrel fold containing the Gln-Tyr-Gly chromophores mainly with cis-conformation. The tetrameric interfaces of tKeima were stabilized by numerous hydrogen bonds and salt–bridge interactions. These key residues distinguish the substituted residues in dKeima and mKeima. The key structure-based residues involved in the tetramer formation of tKeima provide insights into the generation of a new type of monomeric mKeima. This structural analysis expands our knowledge of the Keima family and provides insights into its protein engineering.
Full article
(This article belongs to the Special Issue Protein Structure, Function and Interaction)
Open AccessArticle
SiOx/C Composite Anode for Lithium-Ion Battery with Improved Performance Using Graphene Quantum Dots and Carbon Nanoparticles
by
Sung Won Hwang
Molecules 2024, 29(11), 2578; https://doi.org/10.3390/molecules29112578 - 30 May 2024
Abstract
In this study, a composite was manufactured by mixing graphene quantum dots, silicon oxide, and carbon nanoparticles, and the characteristics of the anode materials for secondary batteries were examined. To improve the capacity of the graphene quantum dot (GQD) anode material, the added
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In this study, a composite was manufactured by mixing graphene quantum dots, silicon oxide, and carbon nanoparticles, and the characteristics of the anode materials for secondary batteries were examined. To improve the capacity of the graphene quantum dot (GQD) anode material, the added silicon oxide content was varied among 0, 5, 10, 15, and 30 wt%, and carbon nanoparticles were added as a structural stabilizer to alleviate silicon oxide volume expansion. The physical properties of the prepared GQD/SiOx/C composite were investigated through XRD, SEM, EDS, and powder resistance analysis. Additionally, the electrochemical properties of the manufactured composite were observed through an analysis of the charge–discharge cycle, rate, and impedance of a lithium secondary battery. In the GQD/SiOx/C composite, by adding carbon nanoparticles, an internal cavity was formed that can alleviate the volume expansion of silicon oxide, and the carbon nanoparticles and silicon oxide particles were uniformly distributed. The formed internal cavity had a silicon oxide content of 5 wt%. Low initial efficiency was observed, and above 30 wt%, low cycle stability was observed. The GQD/SiOx/C composite with 15 wt% of silicon oxide added showed an initial discharge capacity of 595 mAh/g, a capacity retention rate of 92%, and a rate characteristic of 81 at 2 C/0.1 C. Silicon oxide was added to improve the capacity of the anode material, and carbon nanoparticles were added as a structural stabilizer to buffer the volume change of the silicon oxide. To use GQD/SiOx/C composite as a highly efficient anode material, the optimal silicon oxide content and carbon nanoparticle mechanism as a structural stabilizer were discussed.
Full article
(This article belongs to the Section Applied Chemistry)
Open AccessArticle
Chemical Composition, Nutritional, and Biological Properties of Extracts Obtained with Different Techniques from Aronia melanocarpa Berries
by
Alessandra Piras, Silvia Porcedda, Antonella Smeriglio, Domenico Trombetta, Mariella Nieddu, Franca Piras, Valeria Sogos and Antonella Rosa
Molecules 2024, 29(11), 2577; https://doi.org/10.3390/molecules29112577 - 30 May 2024
Abstract
This study investigates the chemical composition, nutritional, and biological properties of extracts obtained from A. melanocarpa berries using different extraction methods and solvents. Hydrodistillation and supercritical fluid extraction with CO2 allowed us to isolate fruit essential oil (HDEX) and fixed
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This study investigates the chemical composition, nutritional, and biological properties of extracts obtained from A. melanocarpa berries using different extraction methods and solvents. Hydrodistillation and supercritical fluid extraction with CO2 allowed us to isolate fruit essential oil (HDEX) and fixed oil (SFEEX), respectively. A phenol-enriched extract was obtained using a mild ultrasound-assisted maceration with methanol (UAMM). The HDEX most abundant component, using gas chromatography-mass spectrometry (GC/MS), was italicene epoxide (17.2%), followed by hexadecanoic acid (12.4%), khusinol (10.5%), limonene (9.7%), dodecanoic acid (9.7%), and (E)-anethole (6.1%). Linoleic (348.9 mg/g of extract, 70.5%), oleic (88.9 mg/g, 17.9%), and palmitic (40.8 mg/g, 8.2%) acids, followed by α-linolenic and stearic acids, were the main fatty acids in SFEEX determined using high-performance liquid chromatography coupled with a photodiode array detector and an evaporative light scattering detector (HPLC-DAD/ELSD). HPLC-DAD analyses of SFEEX identified β-carotene as the main carotenoid (1.7 mg/g), while HPLC with fluorescence detection (FLU) evidenced α-tocopherol (1.2 mg/g) as the most abundant tocopherol isoform in SFEEX. Liquid chromatography-electrospray ionization-MS (LC-ESI-MS) analysis of UAMM showed the presence of quercetin-sulfate (15.6%, major component), malvidin 3-O-(6-O-p-coumaroyl) glucoside-4-vinylphenol adduct (pigment B) (9.3%), di-caffeoyl coumaroyl spermidine (7.6%), methyl-epigallocatechin (5.68%), and phloretin (4.1%), while flavonoids (70.5%) and phenolic acids (23.9%) emerged as the most abundant polyphenol classes. UAMM exerted a complete inhibition of the cholesterol oxidative degradation at 140 °C from 75 μg of extract, showing 50% protection at 30.6 μg (IA50). Furthermore, UAMM significantly reduced viability (31–48%) in A375 melanoma cells in the range of 500–2000 μg/mL after 96 h of incubation (MTT assay), with a low toxic effect in normal HaCaT keratinocytes. The results of this research extend the knowledge of the nutritional and biological properties of A. melanocarpa berries, providing useful information on specific extracts for potential food, cosmetic, and pharmaceutical applications.
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(This article belongs to the Special Issue Phytochemistry and Biological Activity Perspectives of Medicinal Plants)
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Open AccessReview
Exploring the Role of Phenolic Compounds in Chronic Kidney Disease: A Systematic Review
by
Filipa Baptista, Jessica Paié-Ribeiro, Mariana Almeida and Ana Novo Barros
Molecules 2024, 29(11), 2576; https://doi.org/10.3390/molecules29112576 - 30 May 2024
Abstract
Chronic kidney disease (CKD) presents a formidable global health concern, affecting one in six adults over 25. This review explores the potential of phenolic compounds in managing CKD and its complications. By examining the existing research, we highlight their diverse biological activities and
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Chronic kidney disease (CKD) presents a formidable global health concern, affecting one in six adults over 25. This review explores the potential of phenolic compounds in managing CKD and its complications. By examining the existing research, we highlight their diverse biological activities and potential to combat CKD-related issues. We analyze the nutritional benefits, bioavailability, and safety profile of these compounds. While the clinical evidence is promising, preclinical studies offer valuable insights into underlying mechanisms, optimal dosages, and potential side effects. Further research is crucial to validate the therapeutic efficacy of phenolic compounds for CKD. We advocate for continued exploration of their innovative applications in food, pharmaceuticals, and nutraceuticals. This review aims to catalyze the scientific community's efforts to leverage phenolic compounds against CKD-related challenges.
Full article
(This article belongs to the Special Issue Food Chemistry and Bioactive Compounds in Relation to Health, 2nd Edition)
Open AccessArticle
Hydrogen Production by Steam Reforming of Ethanol and Dry Reforming of Methane with CO2 on Ni/Vermiculite: Stability Improvement via Acid or Base Treatment of the Support
by
Hanane Mahir, Abdellah Benzaouak, Farah Mesrar, Adnane El Hamidi, Mohamed Kacimi, Luca Consentino and Leonarda Francesca Liotta
Molecules 2024, 29(11), 2575; https://doi.org/10.3390/molecules29112575 - 30 May 2024
Abstract
In this study, vermiculite was explored as a support material for nickel catalysts in two key processes in syngas production: dry reforming of methane with CO2 and steam reforming of ethanol. The vermiculite underwent acid or base treatment, followed by the preparation
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In this study, vermiculite was explored as a support material for nickel catalysts in two key processes in syngas production: dry reforming of methane with CO2 and steam reforming of ethanol. The vermiculite underwent acid or base treatment, followed by the preparation of Ni catalysts through incipient wetness impregnation. Characterization was conducted using various techniques, including X-ray diffraction (XRD), SEM–EDS, FTIR, and temperature-programmed reduction (H2-TPR). TG-TD analyses were performed to assess the formation of carbon deposits on spent catalysts. The Ni-based catalysts were used in reaction tests without a reduction pre-treatment. Initially, raw vermiculite-supported nickel showed limited catalytic activity in the dry reforming of methane. After acid (Ni/VTA) or base (Ni/VTB) treatment, vermiculite proved to be an effective support for nickel catalysts that displayed outstanding performance, achieving high methane conversion and hydrogen yield. The acidic treatment improved the reduction of nickel species and reduced carbon deposition, outperforming the Ni over alkali treated support. The prepared catalysts were also evaluated in ethanol steam reforming under various conditions including temperature, water/ethanol ratio, and space velocity, with acid-treated catalysts confirming the best performance.
Full article
(This article belongs to the Special Issue Efficient Catalytic CO2 Chemical Fixation)
Open AccessArticle
Total Syntheses and Antibacterial Studies of Natural Isoflavones: Scandenone, Osajin, and 6,8-Diprenylgenistein
by
Hongbo Dong, Yufei Che, Xingtong Zhu, Yi Zhong, Jiafu Lin, Jian Wang, Weihong Du and Tao Song
Molecules 2024, 29(11), 2574; https://doi.org/10.3390/molecules29112574 - 30 May 2024
Abstract
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Isoflavones are a class of natural products that exhibit a wide range of interesting biological properties, including antioxidant, hepatoprotective, antimicrobial, and anti-inflammatory activities. Scandenone (1), osajin (2), and 6,8-diprenylgenistein (3) are natural prenylated isoflavones that share the
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Isoflavones are a class of natural products that exhibit a wide range of interesting biological properties, including antioxidant, hepatoprotective, antimicrobial, and anti-inflammatory activities. Scandenone (1), osajin (2), and 6,8-diprenylgenistein (3) are natural prenylated isoflavones that share the same polyphenol framework. In this research, the key intermediate 15 was used for the synthesis of the natural isoflavones 1–3, establishing a stereoselective synthetic method for both linear and angular pyran isoflavones. The antibacterial activities of 1–3 were also evaluated, and all of them displayed good antibacterial activity against Gram-positive bacteria. Among them, 2 was the most potent one against MRSA, with a MIC value of 2 μg/mL, and the SEM assay indicated that the bacterial cell membranes of both MRSA and E. faecalis could be disrupted by 2. These findings suggest that this type of isoflavone could serve as a lead for the development of novel antibacterial agents for the treatment of Gram-positive bacterial infections.
Full article
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Open AccessReview
Metal–Flavonoid Interactions—From Simple Complexes to Advanced Systems
by
Paulina Katarzyna Walencik, Renata Choińska, Ewelina Gołębiewska and Monika Kalinowska
Molecules 2024, 29(11), 2573; https://doi.org/10.3390/molecules29112573 - 30 May 2024
Abstract
For many years, metal–flavonoid complexes have been widely studied as a part of drug discovery programs, but in the last decade their importance in materials science has increased significantly. A deeper understanding of the role of metal ions and flavonoids in constructing simple
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For many years, metal–flavonoid complexes have been widely studied as a part of drug discovery programs, but in the last decade their importance in materials science has increased significantly. A deeper understanding of the role of metal ions and flavonoids in constructing simple complexes and more advanced hybrid networks will facilitate the assembly of materials with tailored architecture and functionality. In this Review, we highlight the most essential data on metal–flavonoid systems, presenting a promising alternative in the design of hybrid inorganic–organic materials. We focus mainly on systems containing CuII/I and FeIII/II ions, which are necessary in natural and industrial catalysis. We discuss two kinds of interactions that typically ensure the formation of metal–flavonoid systems, namely coordination and redox reactions. Our intention is to cover the fundamentals of metal–flavonoid systems to show how this knowledge has been already transferred from small molecules to complex materials.
Full article
(This article belongs to the Special Issue Antioxidant Activity of Natural Products: 2nd Edition)
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Open AccessArticle
Assessment of the Novel Anti-Seizure Potential of Validamycin A Using Zebrafish Epilepsy Model
by
Eunhye Lee, Amit Banik, Ki-Baek Lee, Seung Min Sim, Ah Hyun Kil, Byung Joon Hwang and Yun Kee
Molecules 2024, 29(11), 2572; https://doi.org/10.3390/molecules29112572 - 30 May 2024
Abstract
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Epilepsy is a prevalent neurological disorder characterized by recurrent seizures. Validamycin A (VA) is an antibiotic fungicide that inhibits trehalase activity and is widely used for crop protection in agriculture. In this study, we identified a novel function of VA as a potential
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Epilepsy is a prevalent neurological disorder characterized by recurrent seizures. Validamycin A (VA) is an antibiotic fungicide that inhibits trehalase activity and is widely used for crop protection in agriculture. In this study, we identified a novel function of VA as a potential anti-seizure medication in a zebrafish epilepsy model. Electroencephalogram (EEG) analysis demonstrated that VA reduced pentylenetetrazol (PTZ)-induced seizures in the brains of larval and adult zebrafish. Moreover, VA reduced PTZ-induced irregular movement in a behavioral assessment of adult zebrafish. The developmental toxicity test showed no observable anatomical alteration when the zebrafish larvae were treated with VA up to 10 µM within the effective range. The median lethal dose of VA in adult zebrafish was > 14,000 mg/kg. These results imply that VA does not demonstrate observable toxicity in zebrafish at concentrations effective for generating anti-seizure activity in the EEG and alleviating abnormal behavior in the PTZ-induced epileptic model. Furthermore, the effectiveness of VA was comparable to that of valproic acid. These results indicate that VA may have a potentially safer anti-seizure profile than valproic acid, thus offering promising prospects for its application in agriculture and medicine.
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Open AccessArticle
The Preparation of g-C3N4/ZnIn2S4 Nano-Heterojunctions and Their Enhanced Efficient Photocatalytic Hydrogen Production
by
Hubing Li, Yaoting Wang, Song Wang and Xin Xiao
Molecules 2024, 29(11), 2571; https://doi.org/10.3390/molecules29112571 - 30 May 2024
Abstract
Hydrogen production technology has triggered a research boom in order to alleviate the problems of environmental pollution and the pressure on non-renewable energy sources. The key factor of this technology is the use of an efficient photocatalyst. g-C3N4 is a
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Hydrogen production technology has triggered a research boom in order to alleviate the problems of environmental pollution and the pressure on non-renewable energy sources. The key factor of this technology is the use of an efficient photocatalyst. g-C3N4 is a typical semiconductor photocatalytic material that is non-toxic and environmentally friendly and does not cause any serious harm to human beings. Therefore, it can be applied to drug degradation and the photocatalytic production of H2. Combined with ZnIn2S4, this semiconductor photocatalytic material, with a typical lamellar structure, has become one of the most promising catalysts for research due to its suitable bandgap structure and excellent photoelectric properties. In this study, 10% g-C3N4/ZnIn2S4 nano-heterojunction composite photocatalytic materials were successfully prepared by compounding ZnIn2S4 and g-C3N4 semiconductor materials with good visible-light-trapping ability. Under visible light irradiation, the photocatalytic activity of the composites was significantly better than that of pure g-C3N4 and ZnIn2S4. This is attributed to the formation of a heterojunction structure, which effectively inhibited the recombination of photogenerated carriers through the interfacial contact between the two semiconducting materials, and then improved the separation efficiency of the photogenerated electron–hole pairs, thus enhancing the catalytic activity. In this study, pure g-C3N4 and ZnIn2S4 were prepared using calcination and hydrothermal methods, and then, the composites were synthesized using ultrasonic and hydrothermal means. The differences in the structure, morphology, and hydrogen production performance of the materials before and after recombination were analyzed in detail using XRD, SEM, and FTIR characterization, which further verified that the 10% g-C3N4/ZnIn2S4 nano-heterojunction composites possessed excellent photocatalytic activity and stability, providing new possibilities for the optimization and application of photocatalytic hydrogen production technology.
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(This article belongs to the Special Issue 2D Nanosheets and Their Nanohybrids)
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Open AccessArticle
Adsorption and Aggregation Behaviors of Oleyl Alcohol-Based Extended Surfactant and Its Mixtures
by
Ping Li, Peiyu Ren, Shuoyu Wang, Jiangshan Wang, Zidan Sun, Jiayi Sun and Weibo Gu
Molecules 2024, 29(11), 2570; https://doi.org/10.3390/molecules29112570 - 30 May 2024
Abstract
An oleyl alcohol-based extended surfactant, sodium oleyl polyethylene oxide-polypropylene oxide sulfate (OE3P3S), was synthesized and identified using FT-IR and 1H NMR. The adsorption and aggregation behaviors of OE3P3S and its mixture with cationic surfactant
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An oleyl alcohol-based extended surfactant, sodium oleyl polyethylene oxide-polypropylene oxide sulfate (OE3P3S), was synthesized and identified using FT-IR and 1H NMR. The adsorption and aggregation behaviors of OE3P3S and its mixture with cationic surfactant alkyltrimethylammoniumbromide (ATAB) were investigated under different molar ratios. The static surface tension analysis indicated that the critical micellization concentration (cmc) and the critical surface tension (γcmc) of OE3P3S were 0.72 mmol/L, and 36.16 mN/m, respectively. The cmc and γcmc values of the binary system were much lower than that of the individual component. And the cmc values of OE3P3S/ATAB = 6:4 mixtures decreased with an increase in the chain length of the cationic surfactant in the binary system. It was found from the dynamic surface tension that there was a slower diffusion rate in the binary system compared to the pure surfactant, and the adsorption processes for OE3P3S/ATAB = 6:4 were mixed diffusion-kinetic adsorption mechanisms. With a combination of DLS data and TEM measurements, formations of vesicles in OE3P3S/ATAB = 6:4 solutions appeared to occur at a concentration of 0.05 mmol/L. By studying the formation of liquid crystal structures in an emulsion prepared with OE3P3S as the surfactant, it was found that the oil-in-water emulsion is birefringent with a Maltese cross texture, and the rheological properties revealed its predominant viscoelastic behavior and shear thinning properties.
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(This article belongs to the Special Issue Surfactants at the Soft Interfacial Layer)
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Open AccessArticle
Non-Substituted Imidazolium-Based Electrolytes as Potential Alternatives to the Conventional Acidic Electrolytes of Polyaniline-Based Electrode Materials for Supercapacitors
by
Fatima Al-Zohbi, Fouad Ghamouss, Johan Jacquemin, Bruno Schmaltz, Mohamad Fadel Tabcheh, Mohamed Abarbri, Khalil Cherry and François Tran-Van
Molecules 2024, 29(11), 2569; https://doi.org/10.3390/molecules29112569 - 30 May 2024
Abstract
Although disubstituted imidazolium cation is sterically crowded, hundreds of ionic liquids based on this cation have been reported as electrolytes for energy storage devices. In contrast to disubstituted imidazolium, non-substituted imidazolium is uncrowded sterically and has not yet been investigated as an electrolyte,
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Although disubstituted imidazolium cation is sterically crowded, hundreds of ionic liquids based on this cation have been reported as electrolytes for energy storage devices. In contrast to disubstituted imidazolium, non-substituted imidazolium is uncrowded sterically and has not yet been investigated as an electrolyte, to the best of our knowledge. Hence, imidazolium hydrogen sulfate [Imi][HSO4], in mixture with water, was studied as an electrolyte for PANI-based electrode materials. For comparison, pyrrolidinium with hydrogen sulfate or p-toluene sulfonate ([Pyrr][HSO4] or [Pyrr][PTS]), in mixture with water, were also investigated as alternatives to the conventional electrolyte (i.e., aqueous H2SO4) for PANI electrodes. Walden plots of binary mixture ionic liquid–water weight ratios with the optimal ionic conductivity (i.e., [Imi][HSO4]/water 48/52 wt% (195.1 mS/cm), [Pyrr][HSO4]/water 41/59 wt% (186.6 mS/cm), and [Pyrr][PTS]/water 48/52 wt% (43.4 mS/cm) along with the electrochemical performances of PANI in these binary mixtures showed that [Pyrr][HSO4]aq or [Imi][HSO4]aq are convenient electrolytes for PANI/PIL, as opposed to [Pyrr][PTS]aq. Furthermore, replacing the conventional aqueous electrolyte H2SO4 with [Imi][HSO4] aq increased the specific capacitance of PANI/PIL from 249.8 to 268.5 F/g at 15 mV/s. Moreover, PANI/PIL electrodes displayed a quasi-ideal capacitive behavior in [Imi][HSO4]aq (the correction factor of CPE4 was 0.99). This primary study has shown that non-substituted imidazolium as an electrolyte could enhance the electrochemical performances of PANI electrodes and could be a good alternative to the conventional electrolyte.
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(This article belongs to the Special Issue Advances of Ionic Liquids in Organic, Polymer and Material Chemistry: Key Trends in Green Chemistry)
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Open AccessArticle
Enhancement of Biodegradability of Chicken Manure via the Addition of Zeolite in a Two-Stage Dry Anaerobic Digestion Configuration
by
Achilleas Kalogiannis, Ioanna A. Vasiliadou, Athanasios Tsiamis, Ioannis Galiatsatos, Panagiota Stathopoulou, George Tsiamis and Katerina Stamatelatou
Molecules 2024, 29(11), 2568; https://doi.org/10.3390/molecules29112568 - 30 May 2024
Abstract
Leach bed reactors (LBRs) are dry anaerobic systems that can handle feedstocks with high solid content, like chicken manure, with minimal water addition. In this study, the chicken manure was mixed with zeolite, a novel addition, and packed in the LBR to improve
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Leach bed reactors (LBRs) are dry anaerobic systems that can handle feedstocks with high solid content, like chicken manure, with minimal water addition. In this study, the chicken manure was mixed with zeolite, a novel addition, and packed in the LBR to improve biogas production. The resulting leachate was then processed in a continuous stirred tank reactor (CSTR), where most of the methane was produced. The supernatant of the CSTR was returned to the LBR. The batch mode operation of the LBR led to a varying methane production rate (MPR) with a peak in the beginning of each batch cycle when the leachate was rich in organic matter. Comparing the MPR in both systems, the peaks in the zeolite system were higher and more acute than in the control system, which was under stress, as indicated by the acetate accumulation at 2328 mg L−1. Moreover, the presence of zeolite in the LBR played a crucial role, increasing the overall methane yield from 0.142 (control experiment) to 0.171 NL CH4 per g of volatile solids of chicken manure entering the system at a solid retention time of 14 d. Zeolite also improved the stability of the system. The ammonia concentration increased gradually due to the little water entering the system and reached 3220 mg L−1 (control system) and 2730 mg L−1 (zeolite system) at the end of the experiment. It seems that zeolite favored the accumulation of the ammonia at a lower rate (14.0 mg L−1 d−1) compared to the control experiment (17.3 mg L−1 d−1). The microbial analysis of the CSTR fed on the leachate from the LBR amended with zeolite showed a higher relative abundance of Methanosaeta (83.6%) compared to the control experiment (69.1%). Both CSTRs established significantly different bacterial profiles from the inoculum after 120 days of operation (p < 0.05). Regarding the archaeal communities, there were no significant statistical differences between the CSTRs and the inoculum (p > 0.05).
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(This article belongs to the Special Issue Novel Biochemical Processes for Treatment and Valorization of Wastes and Biomass)
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Open AccessArticle
Insights into Transfer of Supramolecular Doxorubicin/Congo Red Aggregates through Phospholipid Membranes
by
Anna Stachowicz-Kuśnierz, Paulina Rychlik, Jacek Korchowiec and Beata Korchowiec
Molecules 2024, 29(11), 2567; https://doi.org/10.3390/molecules29112567 - 30 May 2024
Abstract
Doxorubicin (DOX) is a commonly used chemotherapeutic drug, from the anthracycline class, which is genotoxic to neoplastic cells via a DNA intercalation mechanism. It is effective and universal; however, it also causes numerous side effects. The most serious of them are cardiotoxicity and
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Doxorubicin (DOX) is a commonly used chemotherapeutic drug, from the anthracycline class, which is genotoxic to neoplastic cells via a DNA intercalation mechanism. It is effective and universal; however, it also causes numerous side effects. The most serious of them are cardiotoxicity and a decrease in the number of myeloid cells. For this reason, targeted DOX delivery systems are desirable, since they would allow lowering the drug dose and therefore limiting systemic side effects. Recently, synthetic dyes, in particular Congo red (CR), have been proposed as possible DOX carriers. CR is a planar molecule, built of a central biphenyl moiety and two substituted naphthalene rings, connected with diazo bonds. In water, it forms elongated ribbon-shaped supramolecular structures, which are able to selectively interact with immune complexes. In our previous studies, we have shown that CR aggregates can intercalate DOX molecules. In this way, they preclude DOX precipitation in water solutions and increase its uptake by MCF7 breast cancer cells. In the present work, we further explore the interactions between DOX, CR, and their aggregates (CR/DOX) with phospholipid membranes. In addition to neutral molecules, the protonated doxorubicin form, DXP, is also studied. Molecular dynamics simulations are employed to study the transfer of CR, DOX, DXP, and their aggregates through POPC bilayers. Interactions of CR, DOX, and CR/DOX with model monolayers are studied with Langmuir trough measurements. This study shows that CR may support the transfer of doxorubicin molecules into the bilayer. Both electrostatic and van der Waals interactions with lipids are important in this respect. The former promote the initial stages of the insertion process, the latter keep guest molecules inside the bilayer.
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(This article belongs to the Special Issue Advances in Computational and Theoretical Chemistry—2nd Edition)
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Phenanthroline-Mediated Photoelectrical Enhancement in Calix[4]arene-Functionalized Titanium-Oxo Clusters
by
Jinle Hou, Chen Huang, Yuxin Liu, Pengfei Fei, Dongxu Zhang, Konggang Qu, Wenwen Zi and Xianqiang Huang
Molecules 2024, 29(11), 2566; https://doi.org/10.3390/molecules29112566 - 30 May 2024
Abstract
Incorporating two organic ligands with different functionalities into a titanium-oxo cluster entity simultaneously can endow the material with their respective properties and provide synergistic performance enhancement, which is of great significance for enriching the structure and properties of titanium-oxo clusters (TOCs). However, the
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Incorporating two organic ligands with different functionalities into a titanium-oxo cluster entity simultaneously can endow the material with their respective properties and provide synergistic performance enhancement, which is of great significance for enriching the structure and properties of titanium-oxo clusters (TOCs). However, the synthesis of such TOCs is highly challenging. In this work, we successfully synthesized a TBC4A-functionalized TOC, [Ti2(TBC4A)2(MeO)2] (Ti2; MeOH = methanol, TBC4A = tert-butylcalix[4]arene). By adjusting the solvent system, we successfully introduced 1,10-phenanthroline (Phen) and prepared TBC4A and Phen co-protected [Ti2(TBC4A)2(Phen)2] (Ti2-Phen). Moreover, when Phen was replaced with bulky 4,7-diphenyl-1,10-phenanthroline (Bphen), [Ti2(TBC4A)2(Bphen)2] (Ti2-Bphen), which is isostructural with Ti2-Phen, was obtained, demonstrating the generality of the synthetic method. Remarkably, Ti2-Phen demonstrates good stability and stronger light absorption, as well as superior photoelectric performance compared to Ti2. Density functional theory (DFT) calculations reveal that there exists ligand-to-core charge transfer (LCCT) in Ti2, while an unusual ligand-to-ligand charge transfer (LLCT) is present in Ti2-Phen, accompanied by partial LCCT. Therefore, the superior light absorption and photoelectric properties of Ti2-Phen are attributed to the existence of the unusual LLCT phenomenon. This study not only deeply explores the influence of Phen on the performance of the material but also provides a reference for the preparation of materials with excellent photoelectric performance.
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(This article belongs to the Special Issue Metal Coordination Compounds: Synthesis, Electronic Structure, Properties and Application)
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Open AccessArticle
Construction of N-Aryl-Substituted Pyrrolidines by Successive Reductive Amination of Diketones via Transfer Hydrogenation
by
Jianhua Liao, Jinghui Tong, Liang Liu, Lu Ouyang and Renshi Luo
Molecules 2024, 29(11), 2565; https://doi.org/10.3390/molecules29112565 - 30 May 2024
Abstract
N-aryl-substituted pyrrolidines are important moieties widely found in bioactive substances and drugs. Herein, we present a practical reductive amination of diketones with anilines for the synthesis of N-aryl-substituted pyrrolidines in good to excellent yields. In this process, the N-aryl-substituted pyrrolidines
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N-aryl-substituted pyrrolidines are important moieties widely found in bioactive substances and drugs. Herein, we present a practical reductive amination of diketones with anilines for the synthesis of N-aryl-substituted pyrrolidines in good to excellent yields. In this process, the N-aryl-substituted pyrrolidines were furnished via successive reductive amination of diketones via iridium-catalyzed transfer hydrogenation. The scale-up performance, water as a solvent, simple operation, as well as derivation of drug molecules showcased the potential application in organic synthesis.
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(This article belongs to the Section Organic Chemistry)
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Open AccessArticle
Impact of Anchoring Groups on the Photocatalytic Performance of Iridium(III) Complexes and Their Toxicological Analysis
by
Xiao Yao, Linyu Fan, Qian Zhang, Chaoqun Zheng, Xue Yang, Yisang Lu and Yachen Jiang
Molecules 2024, 29(11), 2564; https://doi.org/10.3390/molecules29112564 - 30 May 2024
Abstract
Three different iridium(III) complexes, labelled as Ir1–Ir3, each bearing a unique anchoring moiety (diethyl [2,2′-bipyridine]-4,4′-dicarboxylate, tetraethyl [2,2′-bipyridine]-4,4′-diylbis(phosphonate), or [2,2′-biquinoline]-4,4′-dicarboxylic acid), were synthesized to serve as photosensitizers. Their electrochemical and photophysical characteristics were systematically investigated. ERP measurements were employed to elucidate
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Three different iridium(III) complexes, labelled as Ir1–Ir3, each bearing a unique anchoring moiety (diethyl [2,2′-bipyridine]-4,4′-dicarboxylate, tetraethyl [2,2′-bipyridine]-4,4′-diylbis(phosphonate), or [2,2′-biquinoline]-4,4′-dicarboxylic acid), were synthesized to serve as photosensitizers. Their electrochemical and photophysical characteristics were systematically investigated. ERP measurements were employed to elucidate the impact of the anchoring groups on the photocatalytic hydrogen generation performance of the complexes. The novel iridium(III) complexes were integrated with platinized TiO2 (Pt–TiO2) nanoparticles and tested for their ability to catalyze hydrogen production under visible light. A H2 turnover number (TON) of up to 3670 was obtained upon irradiation for 120 h. The complexes with tetraethyl [2,2′-bipyridine]-4,4′-diylbis(phosphonate) anchoring groups were found to outperform those bearing other moieties, which may be one of the important steps in the development of high-efficiency iridium(III) photosensitizers for hydrogen generation by water splitting. Additionally, toxicological analyses found no significant difference in the toxicity to luminescent bacteria of any of the present iridium(III) complexes compared with that of TiO2, which implies that the complexes investigated in this study do not pose a high risk to the aquatic environment compared to TiO2.
Full article
(This article belongs to the Special Issue Synthesis, Structure, Molecular Modeling, and Bioactivity of Metal Complexes)
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