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Associating molecular structure and mechanical properties is important for silicone rubber design. Although silicone rubbers are widely used due to their odourless, non-toxic, and high- and low-temperature resistance advantages, their application and development are still limited by their poor mechanical properties. The mechanical properties of silicone rubbers can be regulated by designing the cross-link density and cross-linking structure, and altering the molar contents of vinyl in the side groups of methyl vinyl silicone rubber (MVQ) leads to different cross-linking structures and cross-linking densities in the vulcanized rubber. Therefore, this study investigated the differences in molecular parameters and molecular chain structures of unprocessed MVQ rubbers with different vinyl contents. The results showed that MVQ rubbers with high vinyl contents were branched polymers, better facilitating the cross-linking reaction than MVQ rubbers with low vinyl contents. In addition, silicone rubbers with different vinyl contents were co-cross-linked to introduce an inhomogeneous cross-linked network in the silicone rubber to improve its mechanical properties. The cross-linked network properties were analysed by the Flory–Rehner model and Mooney–Rivlin plots, and it was found that the long chains in the sparsely cross-linked domains of the network favoured high elongation at break and the short chains in the densely cross-linked domains contributed to high modulus, which could satisfy the functions of reinforcing and toughening the rubber materials at the same time. It was also found by analysing the filler network and aggregate morphology that the inhomogeneous cross-linked network led to an improvement in the dispersion of silica in the rubber and a significant improvement in the mechanical properties of silicone rubber. [ABSTRACT FROM AUTHOR]

This study investigates polyaniline (PANI) for its sensing characteristics for detecting acetaldehyde. Pristine PANI is further modified in two ways to improve its sensing capabilities: 1) addition of a side chain (i.e., two methyl groups) to form poly (2,5‐dimethylaniline), 2) addition of small amounts of metal oxide dopant (In2O3 in this case) to PANI. All the materials are evaluated for their sensing characteristics with respect to both sensitivity and selectivity. The sensitivity of PANI toward acetaldehyde is found to improve with both types of modification (i.e., poly (2,5‐dimethylaniline) and PANI doped with different wt.% of In2O3). However, upon evaluating selectivity toward acetaldehyde using binary and ternary gas mixtures, pristine PANI exhibited higher selectivity compared to its modified counterparts. [ABSTRACT FROM AUTHOR]

The aryl diester compound, 2-methyl-1,4-phenyl­ene bis­(3,5-di­bromo­benzoate), C21H12Br4O4, was synthesized by esterification of methyl hydroquinone with 3,5-dibromo­benzoic acid. A crystalline sample was obtained by cooling a sample of the melt (m.p. = 502 K/DSC) to room temperature. The molecular structure consists of a central benzene ring with anti-3,5-di­bromo­benzoate groups symmetrically attached at the 1 and 4 positions and a methyl group attached at the 2 position of the central ring. In the crystal structure (space group P1̅), molecules of the title aryl diester are located on inversion centers imposing disorder of the methyl group and H atom across the central benzene ring. The crystal structure is consolidated by a network of C—H⋯Br hydrogen bonds in addition to weaker and offset π–π inter­actions involving the central benzene rings as well as the rings of the attached 3,5-di­bromobenzoate groups. [ABSTRACT FROM AUTHOR]

Pure SnO2 and 1 at.% PdO–SnO2 materials were prepared using a simple hydrothermal method. The micromorphology and element valence state of the material were characterized using XRD, SEM, TEM, and XPS methods. The SEM results showed that the prepared material had a two-dimensional nanosheet morphology, and the formation of PdO and SnO2 heterostructures was validated through TEM. Due to the influence of the heterojunction, in the XPS test, the energy spectrum peaks of Sn and O in PdO–SnO2 were shifted by 0.2 eV compared with SnO2. The PdO–SnO2 sensor showed improved ethanol sensing performance compared to the pure SnO2 sensor, since it benefited from the large specific surface area of the nanosheet structure, the modulation effect of the PdO–SnO2 heterojunction on resistance, and the catalyst effect of PdO on the adsorption of oxygen. A DFT calculation study of the ethanol adsorption characteristics of the PdO–SnO2 surface was conducted to provide a detailed explanation of the gas-sensing mechanism. PdO was found to improve the reducibility of ethanol, enhance the adsorption of ethanol's methyl group, and increase the number of adsorption sites. A synergistic effect based on the continuous adsorption sites was also deduced. [ABSTRACT FROM AUTHOR]

Polydopamine (PDA) has garnered significant interest for applications in biosensors, drug delivery, and tissue engineering. However, similar polycatecholamines like polynorepinephrine (PNE) with additional hydroxyl groups and poly-α-methylnorepinephrine (PAMN) with additional hydroxyl and methyl groups remain unexplored in the biosensing domain. This research introduces three innovative biosensing platforms composed of ternary nanocomposite based on reduced graphene oxide (RGO), gold nanoparticles (Au NPs), and three sister polycatecholamine compounds (PDA, PNE, and PAMN). The study compares and evaluates the performance of the three biosensing systems for the ultrasensitive detection of Mycobacterium tuberculosis (MTB). The formation of the nanocomposites was meticulously examined through UV–Visible, Raman, XRD, and FT-IR studies with FE-SEM and HR-TEM analysis. Cyclic voltammetry and differential pulse voltammetry measurements were also performed to determine the electrochemical characteristics of the modified electrodes. Electrochemical biosensing experiments reveal that the RGO-PDA-Au, RGO-PNE-Au, and RGO-PAMN-Au-based biosensors detected target DNA up to a broad detection range of 0.1 × 10−8 to 0.1 × 10−18 M, with a low detection limit (LOD) of 0.1 × 10−18, 0.1 × 10−16, and 0.1 × 10−17 M, respectively. The bioelectrodes were proved to be highly selective with excellent sensitivities of 3.62 × 10−4 mA M−1 (PDA), 7.08 × 10−4 mA M−1 (PNE), and 6.03 × 10−4 mA M−1 (PAMN). This study pioneers the exploration of two novel mussel-inspired polycatecholamines in biosensors, opening avenues for functional nanocoatings that could drive further advancements in this field. [ABSTRACT FROM AUTHOR]

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The strategic installation of the "magic methyl" group at a certain location in lead compounds has become an important tool for medicinal chemists in the field of drug discovery. Both photochemistry and electrochemistry have witnessed an explosive resurgence in recent years and emerged as a cornerstone of modern organic chemistry. In this review, we conducted an extensive data mining of the literature and provide a comprehensive overview of the recent advancements in utilizing green photochemical and electrochemical methodologies for the incorporation of methyl groups, with specific emphasis on the methyl source, design strategies and reaction mechanisms. These research developments provide sustainable and broadly applicable tools to develop valuable methylated products with major prospects for the pharmaceutical industry. In addition, their applications in the late-stage functionalization of bioactive compounds are also demonstrated. [ABSTRACT FROM AUTHOR]

Facile transmetalation is observed from a d8 metal, platinum(II), to indium and gallium leading to the extrusion of methylated gallate and indate anions representing a rare case of the "reverse" transmetalation from a d8 metal to a main group metal. The Pt–Ga and Pt–In bonding in the bimetallic complexes was analyzed through bosonic and fermionic potentials, QTAIM, and NBO. [ABSTRACT FROM AUTHOR]

DFT calculations were performed for the methyl group transfer reaction between CH3Co (dmgBF2)py and PPh3Ni(Triphos). The reaction mechanism and its energetics were investigated. This reaction is relevant to the catalytic mechanism of the enzyme acetyl coenzyme A synthase. BP86 and PBE functionals and dispersion corrections were used. It was found that intermolecular interactions are very important for this reaction. The influence of the solvent on the reaction was studied. [ABSTRACT FROM AUTHOR]

Tetroxane derivatives are interesting drugs for antileishmaniasis and antimalaric treatments. The gas-phase thermal decomposition of 3,6,-dimethyl-1,2,4,5-tetroxane (DMT) and 3,3,6,6,-tetramethyl-1,2,4,5-tetroxane (acetone diperoxide (ACDP)) was studied at 493–543 K by direct gas chromatography by means of a flow reactor. The reaction is produced in the injector chamber at different temperatures. The resulting kinetics Arrhenius equations were calculated for both tetroxanes. Including the parent compound of the series 1,2,4,5-tetroxane (formaldehyde diperoxide (FDP)), the activation energy and frequency factors decrease linearly with the number of methyl groups. The reaction mechanisms of ACDP and 3,6,6-trimethyl-1,2,4,5-tetroxane (TMT) decomposition have been studied by means of the DFT method with the BHANDHLYP functional. Our calculations confirm that the concerted mechanism should be discarded and that only the stepwise mechanism occurs. The critical points of the singlet and triplet state potential energy surfaces (S- and T-PES) of the thermolysis reaction of both compounds have been determined. The calculated activation energies of the different steps vary linearly with the number of methyl groups of the methyl-tetroxanes series. The mechanism for the S-PES leads to a diradical O···O open structure, which leads to a C···O dissociation in the second step and the production of the first acetaldehyde/acetone molecule. This last one yields a second C···O dissociation, producing O2 and another acetone/acetaldehyde molecule. The O2 molecule is in the singlet state. A quasi-parallel mechanism for the T-PES from the open diradical to products is also found. Most of the critical points of both PES are linear with the number of methyl groups. Reaction in the triplet state is much more exothermic than the singlet state mechanism. Transitions from the singlet ground state, S0 and low-lying singlet states S1–3, to the low-lying triplet excited states, T1–4, (chemical excitation) in the family of methyl tetroxanes are also studied at the CASSCF/CASPT2 level. Two possible mechanisms are possible here: (i) from S0 to T3 by strong spin orbit coupling (SOC) and subsequent fast internal conversion to the excited T1 state and (ii) from S0 to S2 from internal conversion and subsequent S2 to T1 by SOC. From these experimental and theoretical results, the additivity effect of the methyl groups in the thermolysis reaction of the methyl tetroxane derivatives is clearly highlighted. This information will have a great impact for controlling these processes in the laboratory and chemical industries. [ABSTRACT FROM AUTHOR]

Ten isatin-based hydrazone derivatives were synthesized using two subseries, IA (isatin + acetophenone) and IB (isatin + benzaldehyde), and evaluated for their monoamine oxidases (MAOs) inhibitory activity. All the compounds showed stronger MAO-A inhibition than MAO-B, and the IB series showed more effective MAO-A inhibitory activity than IA series. Compound IB4 most potently inhibited MAO-A (half maximal inhibitory concentration IC50 = 0.015 µM), followed by IB3 (IC50 = 0.019 µM). On the contrary, compound IB3 showed the highest MAO-B inhibition (IC50 = 0.068 µM), followed by IB4 (IC50 = 1.87 µM). Compound IB3 and IB4 had low selectivity indices of 3.68 and 8.50, respectively. Structurally, the methyl group of IA series decreased the inhibition of both MAO-A and MAO-B. Among them, IB3 and IB4 (4-Cl and 4-Br in B-ring, respectively) showed higher MAO-A and MAO-B inhibition than the other substitutions. Inhibition constant Ki values of IB3 and IB4 for MAO-A were 0.0088 and 0.0063 µM, respectively, and those for MAO-B were 0.048 and 0.060 µM, respectively. IB3 and IB4 were competitive, reversible inhibitors of MAO-A and MAO-B. Molecular docking analysis predicted that IB3 and IB4 formed stable hydrogen bonds between Asn181 and the NH atom of isatin in the ligand-protein complex. Dynamic analysis revealed that IB3 and IB4 are stable with both MAO isoforms. These observations suggest IB3 and IB4 are potent and reversible MAO-A and MAO-B inhibitors and both compounds can be used as therapeutic agents for neurological disorders. [ABSTRACT FROM AUTHOR]

Genomic DNA methylation patterns play a crucial role in the developmental processes of plants and mammals. In this study, we aimed to investigate the significant effects of epigenetic mechanisms on the development of soybean seedlings and metabolic pathways. Our analyses show that 5‐azaC‐treatment affects radicle development from two Days After Imbibition (DAI), as well as both shoot and root development. We examined the expression levels of key genes related to DNA methylation and demethylation pathways, such as DRM2, which encodes RNA‐directed DNA Methylation (RdDM) pathway, SAM synthase, responsible for methyl group donation, and ROS1, a DNA demethylase. In treated seedling roots, we observed an increase in DRM2 expression and a decrease in ROS1 expression. Additionally, 5‐azaC treatment altered protein accumulation, indicating epigenetic control over stress response while inhibiting nitrogen assimilation, urea cycle, and glycolysis‐related proteins. Furthermore, it influenced the levels of various phytohormones and metabolites crucial for seedling growth, such as ABA, IAA, ethylene, polyamines (PUT and Cad), and free amino acids, suggesting that epigenetic changes may shape soybean responses to pathogens, abiotic stress, and nutrient absorption. Our results assist in understanding how hypomethylation shapes soybean responses to pathogens, abiotic stress, and nutrient absorption crucial for seedling growth, suggesting that the plant's assimilation of carbon and nitrogen, along with hormone pathways, may be influenced by epigenetic changes. [ABSTRACT FROM AUTHOR]

Two 3-(p-substituted phenyl)-3a,8a-dihydro-4H-cyclohepta[d]isoxazoles were synthesized by 1,3-dipolar cycloaddition of the corresponding nitrile oxides with cycloheptatriene. Two endoperoxides were synthesized as facially selective and single products in high yields (93%--95%) from the reactions of isoxazole derivatives with singlet oxygen. The exact configurations of the endoperoxide with a methyl group in the phenyl ring and the diol synthesized from it were confirmed by X-ray analysis. To elucidate the mechanism, the formation energy of the endoperoxide was investigated by simulations using the software package Gaussian 09 and density functional theory calculations via the M06-2X/6-311+G(d,p) level method in dichloromethane. The results were consistent with experimental findings showing the formation of isoxazole products. [ABSTRACT FROM AUTHOR]

For the first time, the oxidative polymerizations of o/m-anisidines and o-toluidine were carried out by ammonium peroxydisulfate in organic medium. According to the results of UV–Vis, 1H NMR and IR spectral methods the structures of the synthesized poly(o-anisidine) coincide with emeraldine base. Formation of dihydrobenzoxazole units was shown for poly(m-anisidine), which lowers the amount of both quinonediimine and methoxy groups in polymer. Obtained polymers show enhanced solubility in organic solvents. Thermal analysis shows that at 800 °C polyanisidines lost only 48% of their initial weight. Room temperature conductivity measurements show correspondingly 2.5 × 10−1 S/cm and 9 × 10−3 S/cm values for poly(o-anisidine) and poly(o-toluidine) when doped with inorganic acids. The ionization potential and electron affinities of obtained polymers were estimated by cyclic voltammograms. [ABSTRACT FROM AUTHOR]

The extraction of Np4+ was studied by a series of N-pivot tripodal diglycolamides, with varying substituents (alkyl groups with varying branching and chain length) and varying spacer length, dissolved in an ionic liquid, i.e. [C4mim][Tf2N]. Out of a series of four ligands, LI (propylene spacer) and LII (ethylene spacer) differ only in the spacer length connecting the three diglycolamide units with the tripodal N platform. While LII – LIV have the same spacer length (ethylene spacer), but LII has a hydrogen atom, LIII has methyl group, and LIV has isopropyl group as a substituent at the amidic N atom close to the central N atom. A reversal extraction mechanism of Np4+ was observed when the spacer chain length reduced from a propylene group in LI to an ethylene group in LII – LIV. While a cation-exchange mechanism was observed in case of LI, a solvation extraction mechanism was seen for the other three ligands with the extracted species being Np(NO3)2(L)2+ for LI, and [Np(NO3)4·L] for LII – LIV. The extraction efficiencies of Np4+ with LII – LIV were significantly affected by the nature of the alkyl substituents and follow the order: LII > LIII > LIV. This trend in the extraction pattern affirms that the alkyl substitution at the amidic N atom creates steric strain in the ligand while complexing with the metal ion. [ABSTRACT FROM AUTHOR]

A series of novel 2‐(2‐pyridyl)quinazoline luminophores containing a donor aryl fragment at position 4 and methyl or methoxy groups at benzene ring has been synthesized by efficient three‐step route. The linear optical properties have been studied by UV/Vis absorption and photoluminescence spectra in two solvents. We revealed that introduction of additional methyl group or the replacement of methyl substituents with methoxy ones lead to sequentially shift of absorption and emission maximum to blue region. 9H‐Carbazol‐9‐yl‐containing derivative is characterized by hypsochromically shifted absorption band compared to its NEt2 and NPh2 counterparts. Unlike 9H‐carbazol‐9‐yl‐derivative, Et2N‐ and Ph2N‐bearing quinazolines demonstrate considerable decrease in quantum yield values when going from toluene to MeCN. Solvatochromic properties have been explored, the pronounced bathochromic shift was observed in fluorescence spectra with the increase of solvents polarity. Moreover, the compounds show significant shift of emission band with the increase of water fraction in DMSO/H2O mixture. Two‐photon optical properties have been also studied, the two‐photon absorption cross‐sections in MeCN and toluene reached 120 GM and 210 GM, respectively. The presence of additional methyl group has little impact on δTPA value, while introduction of methoxy substituents dramatically decreases TPA cross sections. Additionally, a quantum‐chemical calculations of synthesized compounds were performed to support the experimental data. [ABSTRACT FROM AUTHOR]

The aryl diester compound, 2-methyl-1,4-phenylene bis(3,5-dibromobenzoate), C21H12Br4O4, was synthesized by esterification of methyl hydroquinone with 3,5-dibromobenzoic acid. A crystalline sample was obtained by cooling a sample of the melt (m.p. = 502 K/DSC) to room temperature. The molecular structure consists of a central benzene ring with anti-3,5-dibromobenzoate groups symmetrically attached at the 1 and 4 positions and a methyl group attached at the 2 position of the central ring. In the crystal structure (space group P1), molecules of the title aryl diester are located on inversion centers imposing disorder of the methyl group and H atom across the central benzene ring. The crystal structure is consolidated by a network of C--H...Br hydrogen bonds in addition to weaker and offset interactions involving the central benzene rings as well as the rings of the attached 3,5-dibromobenzoate groups. [ABSTRACT FROM AUTHOR]

Thermal atomic layer etching (ALE) is one promising method to achieve atomic level precision and high conformality over three-dimensional structures that can further enable the manufacturing of gate-all-around devices. Initially, an ALE process using CF4/NH3/Ar remote plasma exposure followed by infrared (IR) annealing was studied on SiCO films. The process showed self-limiting behavior and achieved an etch per cycle (EPC) of 0.2 nm/cycle. To increase the EPC, an O2 remote plasma exposure step was added before the CF4/NH3/Ar plasma exposure step in the ALE cycle. The process achieved an EPC of 1.0 nm/cycle. Measurements of the EPC of the SiCO film showed self-limiting behavior in both the O2 and CF4/NH3/Ar steps. X-ray photoelectron spectroscopy results showed an increase in atomic concentration (AC) of oxygen while the AC of carbon decreased following the exposure of the film to an O2 remote plasma. The results indicate that methyl groups (-CH3) in the top layers of the film are being replaced by hydroxyl (-OH) groups and Si-O-Si bonding. The N1s spectrum showed the formation of an ammonium fluorosilicate (NH4)2SiF6-based surface-modified layer following exposure to a CF4/NH3/Ar remote plasma. IR annealing of the film showed desorption of the ammonium fluorosilicate surface-modified layer and the return to an as grown SiCO film surface composition. [ABSTRACT FROM AUTHOR]

The molecular structure of a crystalline monolayer of hydrocarbon chains was modeled and studied via computer simulation using the Metropolis Monte Carlo algorithm at a temperature T = 300 K. The only interactions in this system occur through Lennard‐Jones dispersion forces and short‐range atom‐atom repulsion. The intent was to establish whether the chains were either rigidly extended or twisted via the thermal formation of gauche bonds and apply the results to understand observations made on two possible oleogelators: triacontane and stearic acid. Specifically, we aimed to understand if their observed crystalline monolayer thicknesses are due to gauche‐bond‐shortened hydrocarbon chains oriented perpendicular to the monolayer surface, or to fully extended rigid chains oriented at a tilt angle with respect to the surface. The results showed that crystals of hydrocarbon chains did not include significant gauche bonds, so that all molecules were rigidly extended, thus explaining the experimental data previously reported. Accordingly, TC and SA dimer molecules are packed in crystalline multilayers with tilt angles in relation to the methyl group plane. [ABSTRACT FROM AUTHOR]

This study employs grand canonical Monte Carlo (GCMC) simulations to investigate the impact of functional group modifications (CH3, OH, NH2, and OLi) on the adsorption performance of CH4/N2 on Ni‐MOF‐74. The results revealed that functional group modifications significantly increased the adsorption capacity of Ni‐MOF‐74 for both CH4 and N2. The packed methyl groups in CH3‐Ni‐MOF‐74 create an environment conducive to CH4, leading to the highest CH4 adsorption capacity. The electrostatic potential distribution indicates that the strong electron‐donating effect introduced by the alkali metal Li results in the highest electrostatic potential gradient in Li‐O‐Ni‐MOF‐74, leading to the strongest adsorption of N2, this is unfavorable for CH4/N2 separation. At 1500 kPa the selectivity order of adsorbents for mixed gases was as follows: CH3‐Ni‐MOF‐74 > NH2‐Ni‐MOF‐74 > OH‐Ni‐MOF‐74 > Ni‐MOF‐74 > Li‐O‐Ni‐MOF‐74. This study highlights that CH3‐Ni‐MOF‐74 possesses optimal CH4 selectivity and adsorption performance. Given the current lack of research on functionalized MOF‐74 for the separation of CH4 and N2, the findings of this study will serve as a theoretical guide and provide references for the applications of CH4 adsorption and CH4/N2 separation. [ABSTRACT FROM AUTHOR]

This article discusses the development of a nickel-catalyzed hydroalkynylation reaction of 1,3-dienes with simple alkynes. The researchers used a Xantphos ligand to achieve regioselective hydroalkynylation, producing a variety of allylic alkyne products. They optimized the reaction conditions by adding water, which increased the yield of the desired product. The method demonstrated excellent functional-group tolerance and a wide substrate scope for alkynes. The researchers also proposed a mechanism for the reaction based on previous studies. Further research will focus on asymmetric variants, expanding the reaction scope, and exploring synthetic applications. [Extracted from the article]

The aim of this study was to obtain new halolactones with a gem-dimethyl group in the cyclohexane ring (at the C-3 or C-5 carbon) and a methyl group in the lactone ring and then subject them to biotransformations using filamentous fungi. Halolactones in the form of mixtures of two diasteroisomers were subjected to screening biotransformations, which showed that only compounds with a gem-dimethyl group located at the C-5 carbon were transformed. Strains from the genus Fusarium carried out hydrolytic dehalogenation, while strains from the genus Absidia carried out hydroxylation of the C-7 carbon. Both substrates and biotransformation products were then tested for antimicrobial activity against multidrug-resistant strains of both bacteria and yeast-like fungi. The highest antifungal activity against C. dubliniensis and C. albicans strains was obtained for compound 5b, while antimicrobial activity against S. aureus MRSA was obtained for compound 4a. [ABSTRACT FROM AUTHOR]

Nickel‐catalyzed cross‐electrophile coupling reactions of two aliphatic alcohol derivatives remain a challenge. Herein, we report a nickel‐catalyzed reductive methylation reaction of aliphatic mesylates with methyl tosylate. This reaction provides straightforward access to compounds bearing aliphatic methyl groups from alkyl alcohol derivatives. Isotopically labelled substrates and reagents can be employed in the reaction to provide perdeuterated and 13C‐labelled products. This transformation can be achieved by employing stoichiometric Mn reductant or electrochemically. Additionally, mechanistic experiments show that alkyl iodides are key intermediates in the transformation which undergo a stereoablative reaction via radical intermediates. [ABSTRACT FROM AUTHOR]

Scalable methods for improving the performance and stability of a field-effect transistor (FET) based on two-dimensional materials are crucial for its real applications. A scalable method of encapsulating the exfoliated MoS2 on the SiO2/Si substrate by hexamethyldisilazane (HMDS) is explored here for reducing the influence of interface traps and ambient contaminants. This leads to 25 times reduction in trap density, three times decrease in subthreshold swing, three times increase in the peak field-effect mobility, and a drastic reduction in hysteresis. This performance remains nearly the same after several weeks of ambient exposure of the device. This is attributed to the superhydrophobic nature of HMDS and the SiO2 surface hydrophobization by the formation of covalent bonds between the methyl groups of HMDS and silanol groups of SiO2. [ABSTRACT FROM AUTHOR]

In nature, hydrogen bonding is a common physical occurrence that has a significant impact on the surroundings of anthocyanins. Water molecules will create hydrogen bonds with anthocyanin molecules in various configurations, but the characteristics of these hydrogen bonds will change. Varied hydrogen bonding characteristics have varied impacts on solvent solutions. This research analyzes the differences in hydrogen bonding qualities caused by different methyl structures, as well as the underlying explanations. In this study, the cyanidin and peonidin structures of anthocyanin molecules were calculated in various stable hydrogen bond configurations using the density functional theory B3LYP/6‐31G(d,p), combined with information from the infrared spectroscopy spectrum, atoms in molecules analysis, interaction energy E, and intermolecular hydrogen bond length. The hydrogen bond structure that is the most stable is determined by analyzing it, as well as the effects of replacing the hydroxyl group with a methyl group and any potential underlying causes. Future anthocyanins research can benefit from the precise theoretical reference that this study can offer. [ABSTRACT FROM AUTHOR]

In this work, the reactions of nonacarbonyldiiron with 8‐alkynyloxyquinoline ligands (L1‐L3) and their resultant iron carbonyl complexes (1a, 1b, 2, and 3) are described. The complexes including the ligands were fully characterized by using a variety of spectroscopic techniques. The four complexes were also crystallographically determined. In the reactions, the quinoline N atom underwent cyclization to form a quinolinium skeleton while the C‐H bond of the quinoline at position 2 or the substituted methyl group was cleaved to form Fe‐C bond(s). Meanwhile, the alkynyl triple bond was reduced to a single bond (1a) or double bonds (1b, 2, and 3) to further coordinate the iron in σ‐bonds or η‐bonds. Particularly, pathways of hydrogenation (1a and 2) and/or dehydrogenation (1b and 3) were accompanied by the reactions. Moreover, the oxidation states of the iron centers in these complexes were identified through analyses of their bond formation, FTIR and NMR spectroscopic signals (1H NMR and DEPT‐135) in combination with their diamagnetic nature, that is, iron (0) for 2 and iron (I) for the rest of the diiron complexes. [ABSTRACT FROM AUTHOR]

The reaction of lithium hexa­methyl­disilyl­amide, [Li{N(Si(CH3)3)2}] (LiHMDS), with 4,4-dimethyl-2-phenyl-2-oxazoline (Phox, C11H13NO) in hexane produced colourless crystals of bis­(4,4-dimethyl-2-phenyl-2-oxazoline-κN)(hexa­methyl­disilyl­amido-κN)lithium, [Li(C6H18NSi2)(C11H13NO)2] or [Li{N(Si(CH3)3)2}(Phox)2] in high yield (89%). Despite the 1:1 proportion of the starting materials in the reaction mixture, the product formed with a 1:2 amide:oxazoline ratio. In the unit cell of the C2/c space group, the neutral mol­ecules lie on twofold rotation axes coinciding with the Li—N(amide) bonds. The lithium(I) centre adopts a trigonal–planar coordination geometry with three nitro­gen donor atoms, one from the HMDS anion and two from the oxazolines. All ligands are monodentate. In the phenyl­oxazoline units, the dihedral angle defined by the five-membered heterocyclic rings is 35.81 (5)°, while the phenyl substituents are approximately face-to-face, separated by 3.908 (5) Å. In the amide, the methyl groups assume a nearly eclipsed arrangement to minimize steric repulsion with the analogous substituents on the oxazoline rings. The non-covalent inter­actions in the solid-state structure of [Li{N(Si(CH3)3)2}(Phox)2] were assessed by Hirshfeld surface analysis and fingerprint plots. This new compound is attractive for catalysis due to its unique structural features. [ABSTRACT FROM AUTHOR]

The present study is focused on the use of cubic metal-organic frameworks-5 (MOF-5) and its functionalized form in the removal of phenolic pollutants by molecular dynamics (MD) and Well-tempered metadynamics (WTMD) simulation methods. It was found that the adsorption mechanism of MOF-5s/phenolic compounds is mostly due to the van der Waals and π–π interactions. However, electrostatic and hydrogen bond (HB) interactions also play a significant role in removing phenolic pollutants by MOF-5 and its functionalized form. The results show that the fluorine functional group (F-MOF-5) increases the adsorption capacity of phenol compounds on the adsorbent surface. By functionalizing the MOF-5 with a methyl functional group (CH3-MOF-5), the adsorption strength decreases. The WTMD calculation confirmed that at the most stable state, the free energy (FE) value of system II (the most stable system in functionalized systems with –F functional group) is about −289.528 kJ mol−1. This value is ~5.781 and 35.514 kJ mol−1 more negative than the FE of the I and III systems (the most stable systems in the pristine and CH3-MOF-5/pollutant systems, respectively). Altogether, the results indicate that F-MOF-5 can be considered a more suitable adsorbent than MOF-5 and CH3-MOF-5 for phenolic pollutants removal from the environment for more assessment. [ABSTRACT FROM AUTHOR]

Recently, various carbazole‐based self‐assembled monolayers (SAMs) have been investigated for use in the hole transport layer (HTL) of perovskite solar cells (PSCs). In particular, [4‐(3,6‐dimethyl‐9H‐carbazol‐9‐yl)butyl] phosphonic acid (Me‐4PACz) is attracting attention as an HTL for high‐efficiency PSC due to its potential for high open‐circuit voltage (VOC) and fill factor (FF). However, Me‐4PACz has strong hydrophobicity due to its methyl group (–CH3) and long alkyl chain (C4H8), which makes it difficult to deposit a high‐quality perovskite layer on top of conventionally coated Me‐4PACz. In this study, to overcome these limitations, a new SAM deposition method based on a vacuum‐assisted deposition (VD) process is attempted. As a result, a uniform perovskite layer is deposited on top of Me‐4PACz through a very simple VD process, achieving 20.31% efficiency, which is not only close to the highest efficiency among Me‐4PACz‐based PSCs, but also improved long‐term stability of the device. It is believed that the findings of this study can be a cornerstone for using SAM‐based HTL with high hydrophobicity in the future. [ABSTRACT FROM AUTHOR]

The computation of the rotation barriers of the methyl groups (Me) of tribromomesitylene (TBM) crystals has been carried out. Experimentally, the barriers of the three Me groups of TBM are found to be high and different. These groups do not experience the same hindering environment in the crystal state. For an isolated TBM molecule, the three barriers are equal and very low. We found that a cluster of 21 TBM molecules permits the reproduction of the crystal symmetry and structure of the bulk, with a central molecule surrounded by six molecules in the same plane and seven other molecules in two planes above and below. DFT computations including dispersion corrections have been carried out using the ONIOM procedure. The Me groups of the central TBM molecule were rotated step by step to determine the conformations of lowest and highest energy for each Me, thus allowing estimation of the rotation barriers as the difference between these energies. In doing so, we found the following barrier values, namely 105, 173, and 205 cm−1, whereas the experimental values were 111, 180 and 200 cm−1. [ABSTRACT FROM AUTHOR]

The crystal structure of nintedanib esylate hemihydrate was refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Nintedanib esylate hemihydrate crystallizes in space group P-1 (#2) with a = 11.5137(1), b = 16.3208(4), c = 19.1780(5) Å, α = 69.0259(12), β = 84.4955(8), γ = 89.8319(6)°, V = 3347.57(3) Å3, and Z = 4 at 295 K. Hydrogen bonds are prominent in the crystal structure. The water molecule forms two medium-strength O–H⋯O hydrogen bonds to one of the esylate anions. The protonated nitrogen atom in each cation forms a N–H⋯O hydrogen bond to an esylate anion. The ring N–H groups form strong intramolecular N–H⋯O hydrogen bonds to carbonyl groups. The ring N–H groups form intramolecular N–H⋯O hydrogen bonds to esylate anions. Many C–H⋅⋅⋅O hydrogen bonds (and one C–H⋯N hydrogen bond), with aromatic C–H, methylene groups and methyl groups as donors, are present. The hydrogen bonding patterns of the two cations differ considerably. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®) [ABSTRACT FROM AUTHOR]

Nitroaromatic compounds can photorelease nitric oxide after UV absorption. The efficiency of the photoreaction depends on the molecular structure, and two features have been pointed out as particularly important for the yield of the process: the presence of methyl groups at the ortho position with respect to the nitro group and the degree of conjugation of the molecule. In this paper, we provide a theoretical characterization at the CASPT2//CASSCF (complete active space second-order perturbation theory//complete active space self-consistent field) level of theory of the photorelease of NO for four molecules derived from nitrobenzene through the addition of ortho methyl groups and/or the elongation of the conjugation. Our previously described mechanism obtained for the photorelease of NO in nitrobenzene has been adopted as a model for the process. According to this model, the process proceeds through a reactive singlet–triplet crossing (STC) region that the system can reach from the triplet 3(πOπ*) minimum. The energy barrier that must be surmounted in order to populate the reactive STC can be associated with the efficiency of the photoreaction. Here, the obtained results display clear differences in the efficiency of the photoreaction in the studied systems and can be correlated with experimental results. Thus, the model proves its ability to highlight the differences in the photoreaction efficiency for the nitroaromatic compounds studied here. [ABSTRACT FROM AUTHOR]

The increasing demand for long wavelength neutrons is being motivated by the need to study larger objects and slower motions characterizing the new materials related to the requirements of nowadays science and technology. However, not much work has been done so far towards the identification of materials and conditions able to produce a copious flux of very cold neutrons (VCN) at either stationary or pulsed sources. This work presents the results of a preliminary study aimed at exploring materials that look promising as potential moderators for VCN sources. For this purpose, a search is done for the existence of very low energy excitations in the generalized density of states of some molecular systems, which can be efficient to slow down already cold neutrons by exchanging energy with them. Besides reviewing and improving the available information on methane (II) and methane clathrate, it is found that such objective can be realized by the quantum dynamics corresponding to the librations of the methyl groups in the methyl fluoride and the p-xylene molecules encapsulated in two different molecular hosts at low temperatures. [ABSTRACT FROM AUTHOR]

The enzymes performing protein post-translational modifications (PTMs) form a critical post-translational regulatory circuitry that orchestrates literally all cellular processes in the organism. In particular, the balance between cellular stemness and differentiation is crucial for the development of multicellular organisms. Importantly, the fine-tuning of this balance on the genetic level is largely mediated by specific PTMs of histones including lysine methylation. Lysine methylation is carried out by special enzymes (lysine methyltransferases) that transfer the methyl group from S-adenosyl-L-methionine to the lysine residues of protein substrates. Set7/9 is one of the exemplary protein methyltransferases that however, has not been fully studied yet. It was originally discovered as histone H3 lysine 4-specific methyltransferase, which later was shown to methylate a number of non-histone proteins that are crucial regulators of stemness and differentiation, including p53, pRb, YAP, DNMT1, SOX2, FOXO3, and others. In this review we summarize the information available to date on the role of Set7/9 in cellular differentiation and tissue development during embryogenesis and in adult organisms. Finally, we highlight and discuss the role of Set7/9 in pathological processes associated with aberrant cellular differentiation and self-renewal, including the formation of cancer stem cells. [ABSTRACT FROM AUTHOR]

Luminescent materials with narrowband emission show great potential for diverse applications in optoelectronics. Purely organic phosphors with room-temperature phosphorescence (RTP) have made significant success in rationally manipulating quantum efficiency, lifetimes, and colour gamut in the past years, but there is limited attention on the purity of the RTP colours. Herein we report a series of closed-loop molecules with narrowband phosphorescence by multiple resonance effect, which significantly improves the colour purity of RTP. Phosphors show narrowband phosphorescence with full width at half maxima (FWHM) of 30 nm after doping into a rigid benzophenone matrix under ambient conditions, of which the RTP efficiency reaches 51.8%. At 77 K, the FWHM of phosphorescence is only 11 nm. Meanwhile, the colour of narrowband RTP can be tuned from sky blue to green with the modification of methyl groups. Additionally, the potential applications in X-ray imaging and display are demonstrated. This work not only outlines a design principle for developing narrowband RTP materials but also makes a major step forward extending the potential applications of narrowband luminescent materials in optoelectronics. Luminescent materials with narrowband emissions are vital for optoelectronic applications. Here, the authors achieve room temperature phosphorescence with a FWHM of 30 nm through the multiple resonance effect and showcase its practical application in X-ray imaging. [ABSTRACT FROM AUTHOR]

Springtails use unique compounds for their outermost epicuticular wax layer, often of terpenoid origin. We report here the structure and synthesis of socialane, the major cuticular constituent of the Collembola Hypogastrura socialis. Socialane is also the first regular nonaprenyl terpene with a cyclic head group. The saturated side chain has seven stereogenic centers, making the determination of the configuration difficult. We describe here the identification of socialane and a synthetic approach using the building blocks farnesol and phytol, enantioselective hydrogenation, and α‐alkylation of sulfones for the synthesis of various stereoisomers. NMR experiments showed the presence of an anti‐configuration of the methyl groups closest to the benzene ring and that the other methyl groups of the polyprenyl side‐chain are not uniformly configured. Furthermore, socialane is structurally different from [6+2]‐terpene viaticene of the closely related H. viatica, showing species specificity of the epicuticular lipids of this genus and hinting at a possible role of surface lipids in the communication of these gregarious arthropods. [ABSTRACT FROM AUTHOR]

To further extend the structure-activity relationships (SARs) of 5-aminopyrazoles (5APs) and identify novel compounds able to interfere with inflammation, oxidative stress, and tumorigenesis, 5APs 1–4 have been designed and prepared. Some chemical modifications have been inserted on cathecol function or in aminopyrazole central core; in detail: (i) smaller, bigger, and more lipophilic substituents were introduced in meta and para positions of catechol portion (5APs 1); (ii) a methyl group was inserted on C3 of the pyrazole scaffold (5APs 2); (iii) a more flexible alkyl chain was inserted on N1 position (5APs 3); (iv) the acylhydrazonic linker was moved from position 4 to position 3 of the pyrazole scaffold (5APs 4). All new derivatives 1–4 have been tested for radical scavenging (DPPH assay), anti-aggregating/antioxidant (in human platelets) and cell growth inhibitory activity (MTT assay) properties. In addition, in silico pharmacokinetics, drug-likeness properties, and toxicity have been calculated. 5APs 1 emerged to be promising anti-proliferative agents, able to suppress the growth of specific cancer cell lines. Furthermore, derivatives 3 remarkably inhibited ROS production in platelets and 5APs 4 showed interesting in vitro radical scavenging properties. Overall, the collected results further confirm the pharmaceutical potentials of this class of compounds and support future studies for the development of novel anti-proliferative and antioxidant agents. [ABSTRACT FROM AUTHOR]

The synthesis of novel stereoregular carborane-containing phenylcyclosiloxanes (4, 5, 6, 8, and 12 –SiO– units in the ring) has been developed. The structures of all compounds were confirmed by a series of physicochemical methods. Tris-cis–tris-trans-dodeca[phenyl(1(3-(9-m-carboranyl)propyl)dimethylsiloxy)]cyclododecasiloxane has been studied by NMR spectroscopy and it was found that such a configuration of the ring makes two methyl groups diastereotopic, resulting in magnetic non-equivalence of the protons of these groups. The results of thermal studies of the obtained compounds are also described. [ABSTRACT FROM AUTHOR]

N-aromatic heterocycles (azaarenes) are useful molecules found in many natural products and pharmaceuticals. Their methyl derivatives (methyl azaarenes) are a unique class of molecules. The methyl group can be converted into an aldehyde group in the iodine–DMSO medium via Kornblum oxidation. The heteroaromatic aldehydes generated are of prime importance in medicinal chemistry and can be isolated or can be trapped by nucleophiles to construct diverse azaarene-linked scaffolds. The whole process can be summed up as functionalization of C(sp3)–H to form aldehydes, which are further functionalized to form an array of diversely functionalized azaarenes. This particular reaction system has gained popularity in recent years. In this reaction system, the methyl azaarene first gets iodinated. The alkyl iodide generated in situ meets the requirements of Kornblum oxidation in the presence of DMSO. Kornblum oxidation is one of the most popular and most preferred reactions of oxidation of alkyl halides because of its non-toxic and metal-free nature and mild reaction conditions. Thus, we present a collection of literature, which cover the reports available in the last decade for the C(sp3)–H functionalization of methyl azaarenes in the iodine–DMSO medium during 2013–2023. [ABSTRACT FROM AUTHOR]

The activation of molecular oxygen remains a persistent challenge to the scientific community owing to its poor selectivity, especially towards organic substrates. In biological systems, phenoxazinone synthase and catechol oxidase are two copper-based metalloenzymes that have been extensively studied because of their catalytic properties in the formation of a phenoxazinone core and quinones, which subsequently produce value-added compounds. Inspired by the design of a native catechol oxidase metalloenzyme, two copper(II) complexes (1 and 2) with dipicolylamine (DPA)-derived tridentate ligands L1 (4-methyl-N,N-bis(pyridin-2-ylmethyl)aniline) and L2 (2,4,6-trimethyl-N,N-bis(pyridin-2-ylmethyl)aniline) are synthesized. The tridentate ligands provided similar environmental facilities for attachment with three histidine moieties found in nature and our goal is to understand their biomimicking activity. On the amine nitrogen center, basicity is varied by systematic substitutions via methyl groups, thus affecting the bond strength of the apical chloride atom, which results in increased lability. The ligands were thoroughly characterized using different spectroscopic methods, i.e., FT-IR, 1H NMR, UV-vis spectroscopy, and ESI mass spectrometry. The molecular structures of 1 and 2 were elucidated using single-crystal X-ray diffraction, which confirms their distorted square pyramidal geometries with two distinct chlorines attached in a cis fashion. The investigation of their catalytic abilities was performed under ambient aerobic conditions in methanol with both o-aminophenol and 3,5-ditertbutyl catechol, which provided kinetic values that correlated with their structural modifications. Toluene-appended 1 (kcat 525 h−1 for o-aminophenol and 612 h−1 for 3,5-ditertbutyl catechol) showed almost twice the activities of mesitylene-derived 2 (kcat 255 h−1 for o-aminophenol and 343 h−1 for 3,5-ditertbutyl catechol). Mass spectroscopy supported their probable mechanisms for both substrates and confirmed the involvement of molecular oxygen in the reaction. EPR studies further confirmed radical generation during adduct formation in the case of catechol oxidation. This study offers detailed information regarding metal–ligand cooperation and their biomimicking activity, which directs the importance of designing suitable bioinspired catalysts. [ABSTRACT FROM AUTHOR]

Pectin structures have received increasing attention as emergent prebiotics due to their capacity to promote beneficial intestinal bacteria. Yet the collective activity of gut bacterial communities to cooperatively metabolize structural variants of this substrate remains largely unknown. Herein, the characterization of a pectin methylesterase, BpeM, from Bifidobacterium longum subsp. longum, is reported. The purified enzyme was able to remove methyl groups from highly methoxylated apple pectin, and the mathematical modelling of its activity enabled to tightly control the reaction conditions to achieve predefined final degrees of methyl‐esterification in the resultant pectin. Demethylated pectin, generated by BpeM, exhibited differential fermentation patterns by gut microbial communities in in vitro mixed faecal cultures, promoting a stronger increase of bacterial genera associated with beneficial effects including Lactobacillus, Bifidobacterium and Collinsella. Our findings demonstrate that controlled pectin demethylation by the action of a B. longum esterase selectively modifies its prebiotic fermentation pattern, producing substrates that promote targeted bacterial groups more efficiently. This opens new possibilities to exploit biotechnological applications of enzymes from gut commensals to programme prebiotic properties. [ABSTRACT FROM AUTHOR]

[Display omitted] A series of novel ruthenium(ii) complexes with nitron-type N-heterocyclic carbene ligands containing chelating (N -arylcarbamoyl)methyl or carboxymethyl groups have been synthesized. Their evaluation as precatalysts in the hydrogenation of ketones has revealed that the complex containing three N -mesityl groups (one on the carbamoyl- methyl moiety and two on the triazole moiety) is the most efficient one. [ABSTRACT FROM AUTHOR]

This article describes the study of a thermo-responsive hybrid systems based on polyurethane (PU) modified with sensitive acrylamide derivates. The hybrid systems were synthesized using PU and two acrylamide derivatives (N-isopropylacrylamide (NIPA) and N-isopropylmethacrylamide (NIPMA)) in different proportions. The systems were characterized using infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic light scattering (DLS). Water-uptake capacity and sedimentation rate were also determined. The results showed that the hybrids with 30% acrylamide derivate (AD) showed a T50 of approximately 360 °C indicating that thermal degradation decreased with the addition of NIPA and NIPMA. Additionally, the incorporation of AD increases the glass transition temperature from −34 to −22 °C when 30% AD was used. The hybrids with 30% AD showed a variation in the diameters (above 60%) when the temperature was decreased from 50 to 22 °C. These changes were attributed to the hydrophilic → hydrophobic transition that occurs when measuring below and above the low critical solution temperature (LCST) of the polymer. Furthermore, the extra methyl group in the structure of NIPMA makes the collapse less pronounced than in NIPA, decreasing the relative diameter change by 10%. Sedimentation tests showed that the addition of the hybrid hydrogels in the sand increased the time of decantation by 60%. So, the combination of two thermo-responsive polymers to alter the hydrophilic/hydrophobic balance allows these polymers to modify their conformation at a specific temperature and could be potentially useful as self-suspending support agents or drug delivery systems. [ABSTRACT FROM AUTHOR]

In this work, five phenanthroline derivatives substituted with different methyl groups have been selected to synthesize β‐diketonate‐based europium complexes to check the influence of the substitutions on the degradation effect of those complexes in poly(methyl methacrylate) (PMMA) films. The photophysical properties of Eu(III) complexes, including absorbance, excitation, and emission have been carefully investigated in solution, solid‐state, and doped in PMMA film. In all these states, the complexes exhibit an impressive red emission at 614 nm with a high photoluminescence quantum yield of up to 85 %. The films have been exposed under outdoor, indoor, and dark storage stability lifetime conditions for 1200 hours. The photoluminescence measurements recorded every 400, 800, and 1200 hours demonstrated that the film containing europium complex with phenanthroline ligand substituted by a high number of methyl groups (Eu(TTA)3L5) showed good photoluminescent stability in indoor and dark conditions, and exhibited better resistance to degradation in outdoor conditions compared to other complexes. This study has proved that phenanthroline ligands could be tuned chemically leading to better stability of those types of complexes in films which can be end‐used for future stable optoelectronic devices such as luminescent solar concentrators. [ABSTRACT FROM AUTHOR]

A biradical formed by coordination of the organogold derivative of a nitronyl nitroxide radical with 1,1′-bis(diphenylphosphino)ferrocene was obtained. According to X-ray diffraction data, the Au—Au distance in the biradical structure is short (3.372 Å). The O atoms of paramagnetic groups form short intramolecular contacts with H atoms of cyclopentadienyl anions (2.360 and 2.581 Å) and with methyl H atoms (2.280 and 2.525 Å), as well as intermolecular contacts with H atoms of methyl groups (2.462 and 2.610 Å). Using cyclic voltammetry, it was established that the oxidation of the biradical occurs reversibly in three stages at potentials equal to −34, 232, and 845 mV vs. Ag/AgCl. Density functional calculations and the QTAIM and NBO analyses revealed that there is a weak noncovalent bond between gold atoms in the biradical complex due to partial transfer of an electron from the 5d orbital of one AuI ion to the 6s orbital of the other AuI ion. A weak intramolecular antiferromagnetic exchange interaction (J/kB ≈ −20 K) in the crystal structure was predicted. [ABSTRACT FROM AUTHOR]

Ramalina sp. (Ramalinaceae) is a type of lichen known to contain many active secondary metabolite compounds that have the potential to be used as medicine or medicinal raw materials. One of the biological activities possessed by Ramalina sp. lichen is its anticancer activity. This research aims to isolate and identify active secondary metabolite compounds from the methanol extract of the Ramalina sp. lichen and to find out the cytotoxic activity of the isolated compound against MCF7 breast cancer cells. Compound 1 (usnic acid) was successfully isolated from fraction A. The isolation and purification process was carried out starting with a maceration process using acetone solvent, followed by silica gel column chromatography using a gradient solvent system consisting of n-hexane, n-hexane:EtOAc, EtOAc, EtOAc:MeOH, and MeOH with 5% increment of polarity to obtain 17 fractions (F- 1 to F-17). From the 17 fractions obtained, fraction 3 (F-3) and fraction 4 (F-4) (eluted with n-hexane:EtOAc 30%), which had the same TLC profile, were combined and named as fraction A. Compound 1 (50 mg) is a yellow needle crystal that was formed in a bottle of fraction A, which was obtained after the process of combining fractions F-3 and F-4 and solvent evaporation process. The crystals were then separated and purified with CHCl3 and MeOH. Compound 1 was then characterized based on spectroscopic data. Various spectroscopic analysis data, including FTIR, 1D- and 2D-NMR, and LC-ESI-MS, show that Compound 1 is a dibenzofuran derivative compound with 18 carbons (3 from carbonyl groups (C=O) and 3 from methyl groups) and 2 hydroxyl (-OH). Cytotoxicity assay showed that at a low concentration of 18.75 ug/mL, Compound 1 caused a 67.06% decrease in MCF7 viability [ABSTRACT FROM AUTHOR]

The main focus of this review is to introduce readers to the fascinating class of lipid molecules known as norsteroids, exploring their distribution across various biotopes and their biological activities. The review provides an in-depth analysis of various modified steroids, including A, B, C, and D-norsteroids, each characterized by distinct structural alterations. These modifications, which range from the removal of specific methyl groups to changes in the steroid core, result in unique molecular architectures that significantly impact their biological activity and therapeutic potential. The discussion on A, B, C, and D-norsteroids sheds light on their unique configurations and how these structural modifications influence their pharmacological properties. The review also presents examples from natural sources that produce a diverse array of steroids with distinct structures, including the aforementioned A, B, C, and D-nor variants. These compounds are sourced from marine organisms like sponges, soft corals, and starfish, as well as terrestrial entities such as plants, fungi, and bacteria. The exploration of these steroids encompasses their biosynthesis, ecological significance, and potential medical applications, highlighting a crucial area of interest in pharmacology and natural product chemistry. The review emphasizes the importance of researching these steroids for drug development, particularly in addressing diseases where conventional medications are inadequate or for conditions lacking sufficient therapeutic options. Examples of norsteroid synthesis are provided to illustrate the practical applications of this research. [ABSTRACT FROM AUTHOR]

Metal–organic framework (MOF) membranes with rich functionality and a tunable pore system are promising for molecular separation. However, an inadequate pore microenvironment and low water stability may hamper the extension of their use in gas separation to liquid separation (e.g., organic solvent dehydration). In this study, we report a high‐valence Zr‐MOF membrane with high stability and tunable pore microenvironment, prepared using a mixed‐ligand strategy based on fumarate (fum) and 2‐methylfumarate (mes) ligands for the pervaporation dehydration of alcohols. The introduction of a methyl group in the ligand side chain narrowed the aperture size while balancing the hydrophilicity, thus facilitating the fast and selective permeation of water over alcohol molecules. The resulting mes/fum‐Zr‐MOF membrane with a mes content of 30% displayed excellent butanol/water separation performance with total flux of 5226 g−1·m−2·h−1, separation factor of 1281, and water content of 99.3% in the permeate, transcending the upper‐bound of state‐of‐the‐art MOF and polymer membranes, thereby exhibiting immense potential for alcohols dehydration. [ABSTRACT FROM AUTHOR]

We found that the N6 methyl group of N6-methyladenine is able to hinder the methylation of N6-methyladenine at the N¹ position by DMS. Based on this, we have devised a novel method for detecting N6-methyladenine, which was successfully applied to identify specific m6A loci in 28S rRNA. [ABSTRACT FROM AUTHOR]

The complexity of crude oil composition, combined with the fluctuating oxygen level in contaminated environments, poses challenges for the bioremediation of oil pollutants, because of compound-specific microbial degradation of petroleum hydrocarbons under certain conditions. As a result, facultative bacteria capable of breaking down petroleum hydrocarbons under both aerobic and anaerobic conditions are presumably effective, however, this hypothesis has not been directly tested. In the current investigation, Shewanella putrefaciens CN32, a facultative anaerobic bacterium, was used to degrade petroleum hydrocarbons aerobically (using O2 as an electron acceptor) and anaerobically (using Fe(III) as an electron acceptor). Under aerobic conditions, CN32 degraded more saturates (65.65 ± 0.01%) than aromatics (43.86 ± 0.03%), with the following order of degradation: dibenzofurans > n-alkanes > biphenyls > fluorenes > naphthalenes > alkylcyclohexanes > dibenzothiophenes > phenanthrenes. In contrast, under anaerobic conditions, CN32 exhibited a higher degradation of aromatics (53.94 ± 0.02%) than saturates (23.36 ± 0.01%), with the following order of degradation: dibenzofurans > fluorenes > biphenyls > naphthalenes > dibenzothiophenes > phenanthrenes > n-alkanes > alkylcyclohexanes. The upregulation of 4-hydroxy-3-polyprenylbenzoate decarboxylase (ubiD), which plays a crucial role in breaking down resistant aromatic compounds, was correlated with the anaerobic degradation of aromatics. At the molecular level, CN32 exhibited a higher efficiency in degrading n-alkanes with low and high carbon numbers relative to those with medium carbon chain lengths. In addition, the degradation of polycyclic aromatic hydrocarbons (PAHs) under both aerobic and anaerobic conditions became increasingly difficult with increased numbers of benzene rings and methyl groups. This study offers a potential solution for the development of targeted remediation of pollutants under oscillating redox conditions. [ABSTRACT FROM AUTHOR]