Inspired by the demonstrated ability of static electric fields to drive chemical reactions, we demonstrate that intrinsic interfacial electric fields at organic microdroplet interfaces can drive radical reactions without external catalysts or applied potentials. Using pyridine-dimethyl sulfoxide (DMSO) microdroplets as a model system, we directly confirm the presence of strong interfacial electric fields through induced charge accumulation measurements and Raman spectroscopy. These fields efficiently drive the catalyst-free methylation of pyridine to 2-methylpyridine (21.1 μM/h) under ambient conditions. Mechanistic investigations reveal that the reaction is initiated by the electric-field-induced generation of hydrogen radicals from pyridine, which then triggers an oxygen-mediated cascade to produce methyl radicals from DMSO for the subsequent methylation. This pathway is unequivocally supported by a combination of isotopic labeling, spin-trapping experiments, and density functional theory (DFT) calculations. The successful application of this strategy to other substrates underscores the broad potential of harnessing interfacial electric fields in organic microdroplets for catalyst-free radical-mediated organic reactions.

This research includes the synthesis of some new heterocyclic derivatives (pyridine derivatives), firstly reaction of (2-amino-5-chloropyridine, 2-amino-4- methyl pyridine) With aromatics benzaldehydes (p-bromobenzaldehyde, dimethyl amino benzaldehyde , p-chlorobenzaldehyde, Salicylic aldehyde, p- amino benzaldehyde) to form different derivatives of schiff bases, secondly reaction of Schiff base derivatives with thioglycolic acid to form thiazolidinone derivatives, all resulting compounds characterized by FT-IR.

The near blue light-emitting fluorescence 1-(9-methyl anthracene)-2-(2-methyl pyridine)-benzimidazole-2-thione has been isolated and characterized with a quantum yield of 17.82%.

Using the isoniazid in antituberculosis therapy can lead to mutations in the KatG and inhA genes of Mycobacterium tuberculosis, resulting in the development of resistance and necessitating modifications to the isoniazid compound. This study aims to assess the potential and level of toxicity of modified compounds, namely 4-pyridine carboxylic acid, pyridine aldehyde, and methyl pyridine, on the mycolic acid receptor through a molecular docking approach. PyRx was employed for the docking process using a protocol with an exhaustiveness of 106 and a center grid box at X=42.424, Y=22.4321, and Z=46.6391. Additionally, the ProTox-II website was used to determine the toxicity level of the test compounds. The results obtained from this research consist of the respective affinity values of the test compounds: -6, -5.4, and -5.2 kcal/mol. The toxicity levels of the test compounds are as follows: class 5, class 4, and class 4. All test compounds interact with amino acids on the target protein, specifically with residue numbers Histidine (HIS A:8), Phenylalanine (PHE A:142) through hydrogen bonding, Leucine (LEU A:95) through pi-Sigma (π) bonding, and Valine (VAL A:12) through pi-Alkyl (π) bonding. In conclusion, the 4-pyridine carboxylic acid compound exhibits potential as a promising drug candidate but comes with a high level of toxicity

Type 2 diabetes and nonalcoholic fatty liver diseases (NAFLDs) are promoted by insulin resistance (IR), which alters lipid homeostasis in the liver. This study aims to investigate the effect of N-methylpyridinium (NMP), a bioactive alkaloid of coffee brew, on lipid metabolism in hepatocytes. The effect of NMP in modulating lipid metabolism is evaluated at physiological concentrations in a diabetes cell model represented by HepG2 cells cultured in a high-glucose medium. Hyperglycemia triggers lipid droplet accumulation in cells and enhances the lipogenic gene expression, which is transactivated by sterol regulatory element binding protein-1 (SREBP-1). Lipid droplet accumulation alters the redox status and endoplasmic reticulum (ER) stress, leading to the activation of the unfolded protein response and antioxidative pathways by X-Box Binding Protein 1(XBP-1)/eukaryotic Initiation Factor 2 alpha (eIF2α) Protein Kinase RNA-Like ER Kinase and nuclear factor erythroid 2-related factor 2 (NRF2), respectively. NMP induces the phosphorylation of AMP-dependent protein kinase (AMPK) and acetyl-CoA carboxylase α (ACACA), and improves the redox status and ER homeostasis, essential steps to reduce lipogenesis and lipid droplet accumulation. These results suggest that NMP may be beneficial for the management of T2D and NAFLD by ameliorating the cell oxidative and ER homeostasis and lipid metabolism.

Enhancing mass spectrometry interpretability by ComDim-ICA multi-block analysis: Geographical and varietal traceability of Brazilian Coffea canephora

Application of an aqueous Zn-ion battery is plagued by a water-induced hydrogen evolution reaction (HER), resulting in local pH variations and an unstable electrode-electrolyte interface (EEI) with uncontrolled Zn plating and side reactions. Here, 4-methyl pyridine N-oxide (PNO) is introduced as a redox non-innocent additive that comprises a hydrophilic bipolar N+-O- ion pair as a coordinating ligand for Zn and a hydrophobic ─CH3 group at the para position of the pyridine ring that reduces water activity at the EEI, thereby enhancing stability. The N+-O- moiety of PNO possesses the unique functionality of an efficient push electron donor and pull electron acceptor, thus maintaining the desired pH during charging/discharging. Intriguingly, replacing ─CH3 (electron pushing +I effect) by ─CF3 group (electron pulling ─I effect), however, does not improve the reversibility; instead, it degrades the cell performance. The electrolyte with 2m ZnSO4 + 15mm PNO enables symmetric cell Zn plating/stripping for a remarkable > 10 000h at 0.5mA cm-2 and exhibits coulombic efficiency (CE) ≈99.61% at 0.8mA cm-2 in Zn/Cu asymmetric cell. This work showcases the immense interplay of the electron push-pull of the additives on the cycling.

PurposeThe purpose of this paper is to solve the abrupt deterioration of lubricant performance in high-temperature conditions.Design/methodology/approachThree silver pyrazolyl methyl pyridine complexes with different morphologies were synthesized. A four-ball tribometer was used to assess the tribological characteristics as an additive for pentaerythritol oleate both independently and compound with 1-hexyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide.FindingsThe results showed that when silver complexes and ionic liquids (IL) act independently, sheet silver complex 1 and rod silver complex 2 exhibit good lubricating performance; the optimal antifriction concentration of the ILs is 0.25 Wt.%. The tribological results of the compounds additive of ILs and silver complexes indicate that the wear scar diameter of compound 1 decreased by 16.914%, the wear volume reduced by 7.44% and the lubrication effect surpassed that of the two substances individually; rod compound 2 exhibited an antagonistic effect, intensifying wear; compound 3’s lubrication effect fell between that of the two individual components.Originality/valueThe compound of sheet silver complexes and ILs effectively solves the agglomeration problem of micro/nano lubricant additives. When the interface fails, self-repair is completed, improving the stability and antiwear performance of the lubricating oil.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2024-0128

While Ising criticality in classical liquids has been firmly established both theoretically and experimentally, much less is known about criticality in liquids in which the growth of the correlation length is frustrated by finite-size effects. A theoretical approach for dealing with this issue is the random-field Ising model (RFIM). While experimental critical-exponent values have been reported for magnetic samples (here, we consider γ, ν and η), little experimental information is available for critical fluctuations in corresponding liquid systems. In this paper, we present a study on a binary liquid consisting of 3-methyl pyridine and heavy water in a very light-weight porous gel. We find that the experimental results are in agreement with the theoretical predictions from the RFIM.

Centrosymmetric homo- and heteroleptic core paddle-wheel copper(II) carboxylates; Syntheses, crystal structures, antioxidant, anticancer and enzyme inhibition activity

In this study, 2 flexible and pre-organized tetraamide compounds derived from N-6-[(4-pyridylmethylamino)carbonyl]-pyridine-2-carboxylic acid methyl ester namely 1,2-bis[N,N’-6-(4-pyridylmethylamido)pyridyl-2-carboxyamido]pentane (L1) and 1,2-bis[N,N’-6-(4-pyridylmethylamido)pyridyl-2-carboxyamido]hexane (L2) have been successfully synthesized when reacted with diamines in 1:2 ratio. These new compounds were built from combination of 3 main components, as a trend requires for anion receptor which are (i) 2,6-pyridine dicarboxamide moieties as targeted anion binding host, (ii) amino methyl pyridine pendants arms as the flexible moieties and (iii) pentyl (-C5H10-) and hexyl (-C6H12-) unit as the spacer. Compounds L1-L2 were fully characterized by using elemental analyzer, Fourier transform infrared (FTIR) spectroscopy, gas chromatography-mass spectroscopy (GC-MS), 1H, 2D NOESY and 13C Nuclear Magnetic Resonance (NMR) spectroscopies, and Ultraviolet-visible (UV-Vis) spectroscopies. In this study, anion titration methods were used to identify the affinity towards selected anions. The results showed that L1 (having a pentyl spacer) had the highest affinity towards phosphate anions as compared to L2, where the red shift changes were observed in the UV-vis spectrum at the amide region. HIGHLIGHTS Two novel amide compounds with flexible and pre-organized structure are designed for use as potential anion receptors The flexible moieties at the amide and the linker allow hydrogen bonding interaction of the molecules with variety anions with different geometries Anion titration studies revealed good affinities towards phosphate anions as suggested in Hofmeister trend GRAPHICAL ABSTRACT

Health-related nutritional human studies rely on the validity of dietary data provided by study participants. Reliable biomarkers for food intake help objectify data collected by food frequency questionnaires. They facilitate the monitoring of compliance with the study requirements, e.g., abstinence from food, help clean biased data, and remove non-compliant individuals. Biomarker candidates are often revealed by sophisticated metabolomics analyses of body fluids, e.g., urine or plasma, collected from case and control study populations. However, validation for using a biomarker candidate in real-life scenarios is seldomly executed. Coffee is a food item of high interest because of the abundance of bioactive compounds and the regularity of life-time consumption by a large part of the population. Coffee has been found to positively impact cardiovascular risk, type 2 diabetes, and cognitive decline. Coffee and its health implications, therefore, are of high interest. A suitable dietary biomarker for coffee consumption is desirable for the clear classification of study participants as coffee drinkers or non-coffee drinkers to enable correlation of physiological response to dietary habits, e.g., coffee consumption. Here, we propose the roast coffee compound N-methylpyridinium (NMP) as a promising biomarker of pragmatic use to distinguish a coffee drinker from a non-coffee drinker. NMP is an easily accessible analytical target from the plasma and urine matrix that can help determine precedent exposure to roasted coffee products. We review the published information on the coffee compound N-methylpyridinium in foods, coffee, and plasma/urine after coffee consumption, and evaluate the data in the context of the proposed food biomarker criteria “plausibility”, “time- and dose–response”, “robustness”, “reliability”, “stability”, “analytical performance”, and “reproducibility”. An additional data set is acquired to fill the gaps in the literature. In summary, we conclude that the abundance of NMP can serve as a reliable analytical tool to verify recent consumption of roasted coffee. The use of NMP appears limited to being qualitative, as NMP abundance in coffee and human biosamples is affected by several parameters, e.g., the roasting conditions and the volume and time of coffee consumed.

Abstract A series of zwitterions with varying bridges, connecting N‐methyl pyridinium acceptor, with phenolate donor, are investigated using various methodologies like, HF, B3LYP, CAM‐B3LYP and ωB97xD. In this systematic study effects of various mono aromatic rings as bridges, on the response properties like, the dipole moments (μ), polarizabilities (α), hyperpolarizabilities (β) and adiabatic absorptions were analyzed using CPHF and TDDFT (or TDHF) theories. Compared to many traditional bridges, as well as without a bridge, enhanced nonlinear optical (2ND order NLO) responses were observed for these aromatically bridged zwitterions (with benzene ring as bridge ~5.3 times and ~7.9 times enhanced hyperpolarizabilities were observed compared to either the ethylene bridge or without any bridge cases, respectively). Also, many significant differences and large enhancements in response properties were observed compared to our earlier works on non‐zwitterionic system (~4.3 times enhanced hyperpolarizability—benzene as bridge case). For some bridge cases, 10‐ to 15‐fold enhanced hyperpolarizabilities were observed compared to without any bridge case. This work reports a class of non‐TICT chromophores, promoting bridge aromaticity control on structure–property correlation, as a suitable and efficient chromophore design strategy to create a wide range of function molecular chromophores. Also, unidirectional natures of response properties and large dipole moments can make these zwitterions suitable 1D‐molecular materials for various contemporary technological applications, as poled polymer‐based materials.

Syntheses, crystal structures, optical properties, antibacterial activity and DFT calculations of two tetrachlorocobaltate(II) salts with substituted methyl pyridinium

Copper(II) complexes with a general formula [Cu2(3,4-F2C6H3CH2COO)4(L)2], where L = 2-methylpyridine (1) and 3-methylpyridine (2), are reported here. The FTIR spectra of the complexes confirmed the bridging bidentate coordination mode of the carboxylate ligand. The low (475 and 449 cm−1) and strong (727 & 725 cm−1) intensity bands in the FTIR spectra, due to Cu-N stretches and pyridyl ring vibrations, confirmed coordination of the 2-/3-methyl pyridine co-ligands in complexes 1 and 2, respectively. A binuclear paddlewheel structural arrangement with a square pyramidal geometry was confirmed for copper atoms in the complexes via single-crystal X-ray analysis. The DPPH, •OH radical, and α-amylase enzyme inhibition assays showed higher activities for the complexes than for the free ligand acid. The binding constant (Kb = 1.32 × 105 for 1 and 5.33 × 105 for 2) calculated via UV-VIS absorption measurements and docking scores (−6.59 for 1 and −7.43 for 2) calculated via molecular docking showed higher SS-DNA binding potential for 2 compared to 1. Viscosity measurement also reflected higher DNA binding ability for 2 than 1. Both complexes 1 and 2 (docking scores of −7.43 and −6.95, respectively) were found to be more active inhibitors than the free ligand acid (docking score of −5.5159) against the target α-amylase protein. This in silico study has shown that the herein reported compounds follow the rules of drug-likeness and exhibit good potential for bioavailability.

Sphingoid base (SPH) is a basic structural unit of all classes of sphingolipids. A sphingoid base typically consists of an aliphatic chain that may be desaturated between C4 and C5, an amine group at C2, and a variable number of OH groups located at C1, C3, and C4. Variations in the chain length and the occurrence of chemical modifications, such as methyl branching, desaturation, and hydroxylation, lead to a large structural diversity and distinct functional properties of sphingoid bases. However, conventional tandem mass spectrometry (MS/MS) via collision-induced dissociation (CID) faces challenges in characterizing these modifications. Herein, we developed an MS/MS method based on CID-triggered radical-directed dissociation (RDD) for in-depth characterization of sphingoid bases. The method involves derivatizing the sphingoid amine with 3-(2,2,6,6-tetramethylpiperidin-1-yloxymethyl)-picolinic acid 2,5-dioxopyrrolidin-1-yl ester (TPN), followed by MS2 CID to unleash the pyridine methyl radical moiety for subsequent RDD. This MS/MS method was integrated on a reversed-phase liquid chromatography-mass spectrometry workflow and further applied for in-depth profiling of total sphingoid bases in bovine heart and Caenorhabditis elegans. Notably, we identified and relatively quantified a series of unusual sphingoid bases, including SPH id17:2 (4,13) and SPH it19:0 in C. elegans, revealing that the metabolic pathways of sphingolipids are more diverse than previously known.

This contribution reports structure–property correlations for a series of interesting zwitterions. All the molecules have N-methyl pyridinium as common acceptor (A), dicyanomethanide substituted p-phenylene as common donor (D), coupled through several mono aromatic rings as the bridges. Computations were carried out using HF, B3LYP, CAM-B3LYP and ωB97xD methodologies. The current report deals with a complete methodical study on the effects of various possible mono aromatic rings as bridges, on dipole moments (μ), polarizabilities (α), hyperpolarizabilities (β) and adiabatic absorption properties. This work shows that compared to literature reported traditional bridges, aromatic bridges indeed showed enhanced nonlinear optical responses (10-fold enhanced β in some cases). Results show that unlike the TICT approach, one can be able to design a wide range of non-TICT chromophores by suitable manipulations through aromatic bridges. Aromatic control on the bridges is suggested as an effective approach in the designing of a wide range of efficient molecular chromophores.

The N-methyl pyridinium tosylate (NMPyTs) ionic liquid is used as an efficient, homogeneous, and recyclable catalyst for the synthesis of tetrahydropyridine derivatives via one-pot multi-component condensation of aromatic aldehyde, anilines, and β-ketoesters under ultrasonic irradiations. This protocol was successfully pertinent to a wide range of structurally diverse aromatic aldehydes, substituted anilines, and β-ketoesters. The major characteristics of this technique include operational simplicity, short reaction times, mild reaction conditions, and high yield. Importantly, NMPyTs can undergo up to three recycle runs without any noticeable loss of catalytic activity.

Scheme 6 needs to be corrected, since the whole pathway A in Scheme 6 was missed out, which has impact on the mechanistic explanation of the formation of compound 3 in manuscript.The complete Scheme 6 is shown below.The changes in Scheme 6 are important, as they a ect the overall conclusion of the manuscript.

Effect of CS2 and CO2 adsorption on the thermally-induced spin crossover in ferrous nitroprussides. Nature of the guest-host interactions