Hydrogen Bond Acceptor Research Articles

Solvatomorphism in a series of copper(II) complexes with the 5-phenylimidazole/perchlorate system as ligands.

In the course of an investigation of the supramolecular behaviour of copper(II) complexes with the 5-phenylimidazole/perchlorate ligand system (`blend') remarkable solvatomorphism has been observed. By employing a variety of crystallization solvents (polar protic, polar/non-polar aprotic), a series of 12 crystalline solvatomorphs with the general formula [Cu(ClO4)2(LH)4]·x(solvent) have been obtained [LH = 5-phenylimidazole, x(solvent) = 3.3(H2O) (1), 2(methanol) (2), 2(ethanol) (3), 2(1-propanol) (4), 2(2-propanol) (5), 2(2-butanol) (6), 2(dimethylformamide) (7), 2(acetone) (8), 2(tetrahydrofurane) (9), 2(1,4-dioxane) (10), 2(ethyl acetate) (11) and 1(diethyl ether) (12)]. The structures have been solved using single-crystal X-ray diffraction and the complexes were characterized by thermal analysis and infrared spectroscopy. The solvatomorphs are isostructural (triclinic, P1), with the exception of compound 9 (monoclinic, P21/n). The supramolecular structures and the role of the various solvents is discussed. All potential hydrogen-bond functionalities, both of the [Cu(ClO4)2(LH)4] units and of the solvents, are utilized in the course of the crystallization process. The supramolecular assembly in all structures is directed by strong recurring Nimidazole-H...Operchlorate motifs leading to robust scaffolds composed of the [Cu(ClO4)2(LH)4] host complexes. The solvents are located in channels and, with the exception of the disordered waters in 1 and the diethyl ether in 12, participate in hydrogen-bonding formation with the [Cu(ClO4)2(LH)4] complexes, serving as both hydrogen-bond acceptors and donors (for the polar protic solvents in 2-6), or solely as hydrogen-bond acceptors (for the polar/non-polar aprotic solvents in 7-11), linking the complexes and contributing to the stability of the crystalline compounds.

Effect of anion α-functionalization on the water affinity of thermo-responsive phosphonium acetate-derived ionic liquids

This study presents a facile method for assessing the effect of anion functional group substitution on the water affinity of phosphonium-acetate ionic liquids. By combining the same cation with three different α-substituted carboxylate anions, the effect of anion functional group substitution on the IL miscibility with water and hygroscopicity was experimentally evaluated and rationalized using COSMO-RS sigma profile analysis. Lower critical solution temperature (LCST) phase separation experiments and water vapor partial pressure measurements revealed that there is a stark α-substitution dependency on the affinity of water for acetate [AcO], pivalate [PivO], and trifluoroacetate [TFA] derived tributyl(octyl)phosphonium [P4448] ILs. It was found that the IL water affinities varied as: [P4448][AcO] > [P4448][PivO] > [P4448][TFA]. With the lowest water partial pressure and no LCST driven phase separation, [P4448][AcO] exhibited a high affinity for water. On the other hand, [P4448][PivO] and [P4448][TFA] exhibited LCST-driven phase separation and room temperature immiscibility, respectively, with higher water partial pressures, as a result of relatively weak water affinities. COSMO-RS sigma profile analysis revealed that the aliphatic carboxylate anions should incorporate apolar interactions commensurate with or greater than the polar hydrogen bond acceptor interactions for phase immiscibility of the corresponding IL with water. It was found that the relative magnitudes of apolar and polar interactions, assessed using the anion sigma profile peak intensity ratio (Ir), are directly correlated with the IL water affinity, and inversely correlated with the solution water activity coefficient. Therefore, it was concluded that Ir forms a quantitative link between the structural changes at the molecular level and the bulk water affinity exhibited by the ionic liquid as a whole.

Deep Eutectic Solvent + Water System in Carbon Dioxide Absorption.

In the present work, deep eutectic solvents (DESs) were synthesized in a one-step process by heating the hydrogen bond acceptors (HBAs) tetrabutylammonium bromide and tetrabutylphosphonium bromide, along with two hydrogen bond donors (HBDs) ethanolamine and N-methyldiethanolamine, which were mixed in certain molar ratios. This mixture was then mixed with water to form a DES + water system. The densities of the prepared DES + water systems were successfully measured using the U-tube oscillation method under atmospheric pressure over a temperature range of 293.15-363.15 K. The CO2 trapping capacity of the DES + water systems was investigated using the isovolumetric saturation technique at pressures ranging from 0.1 MPa to 1 MPa and temperatures ranging from 303.15 K to 323.15 K. A semi-empirical model was employed to fit the experimental CO2 solubility data, and the deviations between the experimental and fitted values were calculated. At a temperature of 303.15 K and a pressure of 100 kPa, the CO2 solubilities in the DES + water systems of TBAB and MEA, with molar ratios of 1:8, 1:9, and 1:10, were measured to be 0.1430 g/g, 0.1479 g/g, and 0.1540 g/g, respectively. Finally, it was concluded that the DES + water systems had a superior CO2 capture capacity compared to the 30% aqueous monoethanolamine solution commonly used in industry, indicating the potential of DES + water systems for CO2 capture.

Antibacterial sensitivity, molecular docking, ADMET analysis, synthesis and spectroscopic structural elucidation of benzodioxol linked chalcone derivatives

A series of new and novel Chalcone derivatives designated as BA1 to BA8, was synthesized and investigated in order to explore their potential as pharmaceutical agents. Benzene-di-oxyacetophenone, benzaldehyde and other derivatives were used as reagents by deploying Claisen-Schmidt condensation reaction to synthesized the desired products. Structure elucidation of all the compounds BA1 to BA8 was done by using spectroscopic techniques, such as mass spectrometry, FTIR, 1HNMR, 13CNMR, and HPLC. The chemistry section meticulously outlines the synthesis procedure for a representative chalcone derivative, specifically (2Z)-1-(2H-1,3-benzodioxol-5-yl)-3-phenylprop-2-en-1-one (BA1), encompassing detailed spectral information and purification steps. In-silico investigations were utilized to investigate the drug-likeliness properties and ADMET characteristics of the developed compounds. the newly compounds exhibit the target-oriented protein interaction. The compounds were undergone antibacterial sensitivity and found that the compounds BA1, BA7 and BA8 showed the prominent results on respective species. The drug-likeness investigation involved an evaluation of various properties of the newly synthesized compounds, such as topological polar surface area, molecular weight of the compounds, logarithm of the distribution coefficient, and hydrogen bond acceptors and donors, for all synthesized compounds. These types of derivatives aid in the identification of promising candidates for further drug development. In essence, this all-encompassing study seamlessly integrates experimental synthesis, spectroscopic characterization, in silico predictions, and molecular docking to furnish a comprehensive evaluation of the potential of chalcone derivatives as ground breaking drug candidates. The discerned findings contribute valuable insights to the ongoing endeavors in developing novel compounds with diverse pharmacological activities and enhanced drug-like properties.

The eutectic and physicochemical properties of the carboxylic-acid-based deep eutectic solvents

The excellent performance of the deep eutectic solvent (DES) is consistent with the 12 Principles of Green Chemistry. It is of importance to study the DES’s structural characteristics, thermophysical properties and physicochemical properties, especially the DES’s solid–liquid-equilibrium phase diagrams in the entire mole fraction. In this work, ten DES were prepared using tetrabutylammonium bromide as the hydrogen bond acceptor, and octanoic acid/hexanoic acid as the hydrogen bond donors. The molar ratio ranged from 1:1.25 to 1:4. Then, the solid–liquid-equilibrium phase diagrams were obtained. The eutectics and the corresponding eutectic points were discovered. The nuclear magnetic resonance spectra and the Fourier transform infrared spectra were applied to analyze the interactions in DES. The densities and viscosities of the prepared DES were measured. With the optimized Lydersen-Joback-Reid method combined with Lee-Kesler rules, the critical properties were predicted. And then the results were verified through a density prediction model. The average absolute relative deviation (AARD) is better than 1.38%. The mass-connectivity-index-based model was introduced for density prediction with AARD of less than 0.17%. For the viscosity, the Arrhenius equation was compared with an equation considering the molar mass. The AARD of them were less than 2.68 % and 0.69 %, respectively.

Deep eutectic solvents: Quantum chemical investigation, thermal stability and physicochemical properties

The current quantum-based research focuses on the eutectic mixtures formulated by combining hydrogen bond donors (Urea, Lactic acid, Xylitol, Proline Xylitol) and acceptor (Betaine, Choline chloride, Proline) molecules. The quantum chemical investigation reveals that DESs Choline chloride-Proline and Choline chloride-Xylitol are the best solvents with the lowest energy gap, highest chemical softness, and the least chemical hardness. FTIR spectroscopy spectra provided evidence of the production of new hydrogen bonds between the two DES components, illuminating the mechanisms behind the impact of the components on the physicochemical characteristics of the DESs. The thermal stability, viscosity, electrical conductivity of DESs under the effect of type of HBAs/HBDs was studied. The influence of the water on the electrical conductivity, density and viscosity are discussed. The initiation of decomposition temperatures for DESs was derived from dynamic thermogravimetric analysis (TGA). DESs have the second level of thermal stability, which means they can be used in technological processes with a range of operating temperatures within ∼ 100–150 °C.

Maximizing Degumming Efficiency for Firmiana simplex Bark Using Deep Eutectic Solvents.

Degumming is a critical process in the purification of natural fibers, essential for enhancing their quality and usability across various applications. Traditional degumming methods employed for natural fibers encounter inherent limitations, encompassing prolonged procedures, excessive energy consumption, adverse environmental impact, and subpar efficiency. To address these challenges, a groundbreaking wave of degumming technique has emerged, transcending these constraints and heralding a new era of efficiency, sustainability, and eco-friendly techniques. This study represents the Firmiana simplex bark (FSB) fiber's delignification by using deep eutectic solvents (DESs). The study explores the application of deep eutectic solvents, by synthesizing different types of DES using a hydrogen bond acceptor (HBA) and four representative hydrogen bond donors (HBDs) for FSB fiber degumming. This study investigates the morphologies, chemical compositions, crystallinities, and physical properties of Firmiana simplex bark fibers before and after the treatment. Furthermore, the effects and mechanisms of different DESs on dispersing FSB fibers were examined. The experimental results showed that choline chloride-urea (CU)-based DES initiates the degumming process by effectively disrupting the hydrogen bond interaction within FSB fibers, primarily by outcompeting chloride ions. Following this initial step, the DES acts by deprotonating phenolic hydroxyl groups and cleaving β-O-4 bonds present in diverse lignin units, thereby facilitating the efficient removal of lignin from the fibers. This innovative approach resulted in significantly higher degumming efficiency and ecofriendly as compared to traditional methods. Additionally, the results revealed that CU-based DES exhibits the utmost effectiveness in degumming FSB fibers. The optimal degumming conditions involve a precise processing temperature of 160 °C and a carefully controlled reaction time of 2 h yielding the most favorable outcomes. The present study presents a novel straightforward and environmentally friendly degumming method for Firmiana simplex bark, offering a substantial potential for enhancing the overall quality and usability of the resulting fibers. Our findings open new pathways for sustainable fiber-processing technologies.

Pharmacophore guided deep learning approach to identify novel inhibitors targeting mycobacterial polyketide synthase Pks13-TE domain

Tuberculosis (TB), an enduring global health challenge, persists due to the rise of drug-resistant Mycobacterium tuberculosis (MTB) strains. Among potential therapeutic targets, Pks13, a protein crucial for mycolic acid biosynthesis, is key for Mtb's virulence and survival. This study employed a pharmacophore-based drug design approach, employing the Pharmacophore-Guided Molecular Generation (PGMG) tool to target Pks13 inhibitors. Aromatic, hydrophobic, positive ion and hydrogen bond acceptors pharmacophoric features were identified from co-crystal ligands. Candidate compounds underwent evaluation of pharmacokinetic properties with the ADMET_AI tool. Further refinement involved molecular docking with PLANTS software, absolute binding free energy calculations via KDeep, and toxicity assessments using eToxPred. MM-GBSA, PCA, DCCM, and FEL were incorporated to validate and refine inhibitors accurately. From this analysis, we discovered five novel hit molecules. These includes, ethyl (S)-4-(4-(2-(2-(cyclohexylamino)-2-oxoethoxy)-2-oxoethoxy)phenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (Pk1), 2-(4-((2‑butyl‑6-pivalamido-1H-benzo [d]imidazol-1-yl)methyl)phenoxy)acetic acid (Pk2), (S)-2-(4-(4-cyclopentyl-5-(1-((6-methyl-2-morpholinopyrimidin-4-yl)amino)ethyl)-4H-1,2,4-triazol-3-yl)phenoxy)acetic acid (Pk3), (E)-2-(4-oxo-5-(4-((6-phenylpyridin-2-yl)methoxy)benzylidene)-2-thioxothiazolidin-3-yl)acetic acid (Pk4), and N-((1R,4r)-4-(((1R,2r,3S,5S,7S)-5‑hydroxy adamantan-2-yl)oxy)cyclohexyl)-4-morpholinobenzamide (Pk5). We conclude that the screened hit compounds may act as potential inhibitors targeting Pks13 and further preclinical and clinical studies may pave the way for developing them as effective therapeutic agents for the treatment of MTB.

Natural deep eutectic solvent for the simultaneous derivatization and microextraction of isoniazid from human plasma

BackgroundPersonalized medicine is a rapidly revolving field that offers new opportunities for tailoring disease treatment to individual patients. The main idea behind this approach is to carefully select safe and effective medications and treatment plant based on each patient's unique pharmacokinetic profile. Isoniazid is a first-line anti-tuberculosis drug that has interindividual variability in its metabolic processing, leading to significant differences in plasma concentrations among patients receiving equivalent doses. This variability necessitates the creation of individualized treatment regimens as part of personalized medicine to achieve more effective therapy. ResultsIn this work, a deep eutectic solvent-based liquid-liquid microextraction approach for the separation and determination of isoniazid in human plasma by high-performance liquid chromatography with UV–Vis detection was developed for the first time. A new natural deep eutectic solvent based on thymol as a hydrogen bond donor and 4-methoxybenzaldehyde as a hydrogen bond acceptor was proposed as the extraction solvent. The developed microextraction procedure assumed two simultaneous processes during the mixing of the sample and extraction solvent: the derivatization of the polar analyte in the presence of 4-methoxybenzaldehyde (component of the natural deep eutectic solvent) with the formation of a hydrophobic Schiff base (1); mass transfer of the Schiff base from the sample phase to the extraction solvent phase (2). Under optimal conditions, the limits of detection and quantification were 20 and 60 μg L−1, respectively. The RSD value was <10 %, the extraction recovery was 95 %. SignificanceIn this work, the possibility of isoniazid derivatization in the natural deep eutectic solvent phase with the formation of the Schiff base was presented for the first time. The approach provided the separation and preconcentration of polar isoniazid without the use of expensive derivatization agents and solid-phase extraction cartridges. The formation of the Schiff base was confirmed by mass spectrometry.

Deep Eutectic Solvents-Based Ultrasonic-Assisted Dispersive Liquid-Liquid Microextraction for the Determination of Organophosphorus Pesticides in Honeysuckle Dew Samples.

A deep eutectic solvent (DES) with the ability to change from hydrophilic to hydrophobic was designed and synthesized and applied to the determination of organophosphorus (OPP) pesticides in honeysuckle dew samples. Choline chloride, phenol, and tetrahydrofuran (THF) were used as the hydrogen bond acceptor, hydrogen bond donor, and demulsifier, respectively. Eight OPP pesticides were extracted by DES coupled with ultrasonic-assisted extraction (UA) and then chromatographed by GC-MS. DES used as an extract solvent has the advantages of high extraction efficiency, low cost, and environmental protection. Furthermore, DES is compatible with GC-MS. The single factor experiment design and Box-Behnken design (BBD) were applied to the optimization of experimental factors, including the type and composition of extraction solvent, type of demulsifier solvent, the volume of DES and THF, pH of sample solution, and ultrasonic time. Under the optimum experimental conditions, the high degree of linearity from 0.1 to 20.0 ng mL-1 (R2 ≥ 0.9989), the limits of detection from 0.014 to 0.051 ng mL-1 (S/N = 3), and the recoveries of analytes from 81.4 to 104.4% with relative standard deviation below 8.6%. In addition, the adsorption mechanism of OPPs on DES was explored by adsorption kinetic studies. These results have demonstrated that the present method has offered an effective, accurate, and sensitive methodology for OPP pesticides in honeysuckle dew samples, and this method provides a reference for the detection of pesticide residues in traditional Chinese medicine.

Investigation of the site 2 pocket of Grp94 with KUNG65 benzamide derivatives

Glucose-regulated protein 94 (Grp94) is an isoform of the heat shock protein 90 kDa (Hsp90) family of molecular chaperones. Inhibiting Grp94 has been implicated for many diseases. Co-crystal structures of two generations of Grp94 inhibitors revealed the importance of investigating the ester group, which is projected into the site 2 pocket unique to Grp94. Therefore, a series of KUNG65 benzamide analogs was designed and synthesized to evaluate their impact on the affinity and selectivity for Grp94. The data demonstrated that substituents with small and saturated ring systems that contain hydrogen bond acceptors exhibited increased affinity for Grp94, whereas larger saturated ring system manifested increased selectivity for Grp94 over Hsp90α.

Hydrophobic binary mixtures containing amphotericin B as lipophilic solutions for the treatment of cutaneous leishmaniasis

Cutaneous leishmaniasis, caused by Leishmania parasites, requires treatments with fewer side effects than those currently available. The development of a topical solution based on amphotericin B (AmB) was pursued. The considerable interest in deep eutectic solvents (DESs) and their remarkable advantages inspired the search for a suitable hydrophobic excipient. Various mixtures based on commonly used hydrogen bond donors (HBDs) and acceptors (HBAs) for DES preparations were explored. Initial physical and in-vitro screenings showed the potential of quaternary phosphonium salt-based mixtures. Through thermal analysis, it was determined that most of these mixtures did not exhibit eutectic behavior. X-ray scattering studies revealed a sponge-like nanoscale structure. The most promising formulation, based on a combination of trihexyl(tetradecyl)phosphonium chloride and 1-oleoyl-rac-glycerol, showed no deleterious effects through histological evaluation. AmB was fully solubilized at concentrations between 0.5 and 0.8 mg·mL−1, depending on the formulation. The monomeric state of AmB was observed by circular dichroism. In-vitro irritation tests demonstrated acceptable viability for AmB-based formulations up to 0.5 mg·mL−1. Additionally, an ex-vivo penetration study on pig ear skin revealed no transcutaneous passage, confirming AmB retention in healthy, unaffected skin.

Comprehensive evaluation of physical properties and carbon dioxide capacities of new 2-(butylamino)ethanol-based deep eutectic solvents

Abstract The aim of this research was to assess the impact of the components of alkanolamine deep eutectic solvents (DESs) on the physical properties of those DESs and their carbon dioxide capacity. To achieve this goal, novel deep eutectic solvents were synthesized by using 2-(butylamino)ethanol (BAE) as the hydrogen bond donor (HBD), along with tetrabutylammonium bromide TBAB), tetrabutylammonium chloride (TBAC), or tetraethylammonium chloride (TEAC) as the hydrogen bond acceptors (HBA) at various molar ratios (1:6, 1:8, and 1:10). To confirm the presence of hydrogen bond interactions between the components Fourier Transform Infrared Spectroscopy measurements were conducted. Furthermore, thermal properties, including melting points and thermal stability, of these deep eutectic solvents as well as key physical properties, such as density, viscosity, refractive index, and sound velocity, within the temperature range of 293.15–333.15 K and at a pressure of 0.1 MPa were examined. The effect of the molar ratio of HBA to HBD, the type of anion, and the length of the alkyl chain were studied and analysed in regard to physicochemical properties. In this work, the solubility of carbon dioxide in DESs derived from 2-(butylamino)ethanol, 3-aminopropan-1-ol (AP), and 2-(methylamino)ethanol (MAE) was measured. The highest CO2 capacity was found for TEAC:MAE 1:10 DES characterized by the shortest alkyl chain length in both HBA and HBD molecules, the highest amine content, and the lowest viscosity. Additionally, the effect of water addition on carbon dioxide solubility was explored. The results showed that the influence of water on CO2 solubility varies with the type of DES. In general, this work highlighted that DESs can serve as effective media for carbon dioxide capture, and their performance can be tailored by changing the type of hydrogen bond acceptor or donor, their molar ratio and by the addition of water.

Effect of water on eutectic solvents: Structural properties and physical interactions with CO2

Deep eutectic solvents (DESs) are versatile solvents for various applications including CO2 separations due to their good solvent strength, low volatilities, high thermal stabilities, and tunable properties. Properties of DESs alter with the presence of water and especially in applications where the solvent is in direct contact with air such as CO2 removal from the atmosphere. This study employs classical molecular dynamics (MD) simulations to examine the impact of water (0 to 70 wt%) on the liquid structure and physical interactions in a eutectic solvent composed of an ionic liquid (IL) 1-ethyl-3-methylimidazolium 2-cyanopyrrolide, [EMIM][2CNPyr], that functions as a hydrogen bond acceptor (HBA) and with three different hydrogen bond donors (HBDs): ethylene glycol (EG), propylene glycol (PG), and monoethanolamine (MEA). It is found that water preferentially solvates HBDs and weakens the hydrogen-bonding interactions between [2CNpyr] and the HBDs, thus resulting in significant structural changes that lead to enhanced interactions between CO2 and [EMIM], [2CNpyr], and MEA. Although these systems represent CO2-chemisorbing solvents in practice, the physical interactions in the presence of water as examined herein provides guidance on their phase behavior and tuning of physical properties by composition for targeted applications including CO2 separations.

Systematic study on date palm seeds (Phoenixdactylifera L.) extraction optimisation using natural deep eutectic solvents and ultrasound technique

Natural deep eutectic solvents (NADES) are emerging, environment-friendly solvents that have garnered attention for their application in extracting phenolic compounds. This study investigated the effects of four synthetic NADES on polyphenols extracted from date seeds (DS) using choline chloride (ChCl) as a hydrogen-bond acceptor and lactic acid (La), citric acid (Citri), glycerol (Gly), and fructose (Fruc) as hydrogen-bond donors, in comparison with DS extracts extracted by conventional solvents (water, 70% methanol, and 70% ethanol). The antioxidant activity (DPPH), total phenolic content (TPC) and 6 phenolic compounds were determined using HPLC. The results showed that the ChCl–La and ChCl–Citri systems exhibited a high extraction efficiency regarding TPC, and DPPH in the DS extracts extracted by NADES compare to those DS extracts extracted with conventional solvents (p ˂ 0.001). HPLC results demonstrated that DS extracted by ChCl–La contained all measured phenolic compounds. Also gallic acid and catechin were the major compounds identified in the DS extracts. In addition DS extracted by ChCl–Citri and ChCl–Gly had the highest concentration of catechin. In conclusion, combining NADES is a promising and environment-friendly alternative to the conventional solvent extraction of phenolic compounds from DS.

LOW-TEMPERATURE CALORIMETRIC CHARACTERIZATION OF DEEP EUTECTIC SOLVENTS WITH ADDED WATER

Deep eutectic solvents (DES) are combinations of hydrogen bonds donors and acceptors, characterized by significantly lower freezing temperatures than their components. NADES (with natural, biologically compatible components) are becoming popular for a wide applications variety, for their wide solvent capacities, non-toxicity, biodegradability, and inexpensive components. Applications include new means for bioactive compounds extraction and enzymatic reactions, polymer solubilizing and a variety of physicochemical processes, including those taking place at low temperature. Four DES (β-alanine and DL-malic or citric acid (plus water) and choline chloride and ethylene glycol or glycerol) were investigated by differential scanning calorimetry (DSC) at low temperature. Pure DES behave completely reversibly, proof of physicochemical stability. Alanine-DES present glass transitions between -40 and -80°C. Meanwhile, choline-DES show no thermal events between 0° and -80°C. Increasing water produce glass transitions in all DES at decreasing temperatures, and devitrifications and freezing events. Choline-DES show no effects up to 20% water. However, alanine-DES show strong water effects, possibly phase separation into different water populations. Calcium alginate-sucrose beads were used as structural model for diffusion systems. Beads were incubated in DES (20 min/20 hours) and their low-temperature properties characterized. Short incubation periods were enough to radically alter their thermal behavior.

Ab initio molecular dynamics study of hydroxyl positioning in butanediol and its impact on deep eutectic solvent structure

Electrolytes play a crucial role in enhancing the performance of energy storage devices, including batteries and supercapacitors. However, traditional electrolytes, such as aqueous solutions, organic solvents, and ionic liquids, exhibit inherent limitations and challenges. Deep eutectic solvents have recently emerged as promising alternatives due to their environmentally friendly nature and favorable properties. Despite their widespread applications in various domains, their potential as electrolytes remains relatively underexplored. This study investigates three distinct types of deep eutectic solvents derived from different isomers of butanediols combined with choline chloride. Ab initio molecular dynamics simulations are employed to analyze the microstructure of these deep eutectic solvents, focusing on non-covalent electrostatic interactions, hydrogen bonding patterns, and vibrational spectra. The results reveal significant differences in the structural configuration of hydrogen bond acceptors and hydrogen bond donors and their interactions within the deep eutectic solvents. Specifically, the positioning of functional groups in hydrogen bond donors significantly impacts the hydrogen bonding network and the interaction with monoatomic ions. Moreover, the vibrational spectra analysis highlights the existence of hydrogen bonds involving stretching modes of the OH group, as evidenced by redshift deviations. Overall, this study provides valuable insights into the unique features of deep eutectic solvents as potential electrolytes for energy storage applications. The comprehensive analysis of their microstructure and vibrational properties enhances our understanding of deep eutectic solvent utilization and opens avenues for further research in sustainable energy storage.

Novel tributyl phosphate-based deep eutectic solvent: Application in microwave assisted extraction of carotenoids

A contribution to the use of deep eutectic solvents (DES) and microwave-assisted extraction (MAE) was made for bioactive compounds recovery, especially those with lipophilic character, from tomato and carrot samples rich in carotenoids. For the first time, a novel deep eutectic solvent was synthesized, comprising tributyl phosphate (TBP) as a hydrogen bond acceptor and acetic acid (AcOH) as a hydrogen bond donor. The total antioxidant capacity (TAC) of tomato and carrot extracts obtained by MAE, in which optimization of operational parameters and modeling were made with the use of Box-Behnken design of the response surface methodology (RSM), was evaluated using the Cupric Reducing Antioxidant Capacity (CUPRAC) method. For the highest TAC, operational parameters that best suit the MAE procedure were set at 80 °C, 35 min, and 25 mL/2.0 g. The TAC values of extracts obtained by MAE using TBP:AcOH, 1:2 (mol/mol) were examined against those of extracts acquired by classical solvent extraction using a mixture of hexane, ethanol and acetone (H:E:A, 2:1:1 (v/v/v)) mixture. TAC of extracts in DES varied between 5.10 and 0.71 lycopene equivalents (mmol LYC kg−1). The highest extraction yield comparable to conventional organic solvents was obtained with TBP:AcOH (1:2). It was observed that, in addition to lipophilic antioxidants, some hydrophilic antioxidant compounds were partially extracted with the proposed DES. Moreover, the extracted antioxidant compounds were identified and quantified by HPLC analysis. The proposed DES and MAE process will find potential application for hydrophobic antioxidant extraction from tomatoes and carrots on an industrial scale after further studies.

Comparison between acetonitrile-water separation by betaine and betaine hydrochloride

Acetonitrile and water are miscible solvents. This study compares their separation by betaine and betaine hydrochloride. Acetonitrile is a hydrogen (H) bond acceptor and so is betaine, because of its -CO and -CO- groups. Therefore, betaine competes with acetonitrile for interactions with the hydrogens of water molecules, as indicated by attenuated total reflectance - Fourier transform infrared spectroscopy (ATR-FTIR). Therefore, when added to acetonitrile-water mixtures, betaine displaces acetonitrile. Separation into bulk phases occurs with 5–10 wt% betaine (relative to water), for acetonitrile concentrations between 50 and 80 wt% (relative to the aqueous phase). At lower acetonitrile concentrations (e.g., 1 wt%), betaine separates acetonitrile from water to yield emulsified acetonitrile droplets, detected by light scattering. With 1 wt% acetonitrile and betaine, acetonitrile droplets in water are negatively charged due to the -CO- group of betaine, as shown by electrophoretic measurements. In the case of betaine hydrochloride, the negative charge of the -CO- group is shielded by a proton, and interactions with water are weaker. As a result, bulk separation is not observed. Nonetheless, betaine hydrochloride also competes against acetonitrile for interactions with hydrogen atoms of water molecules, albeit not as effectively as betaine. This is shown by ATR-FTIR. Therefore, betaine hydrochloride emulsifies acetonitrile in water into sub-micron droplets. These droplets are positively charged, owing to the positively charged nitrogen atom of betaine hydrochloride. Acidifying mixtures of betaine, acetonitrile and water (with HCl) impedes bulk separation. This result confirms the importance of electrostatic interactions between the hydrogens of water and the unshielded, negative -CO- group of betaine.

Oxime Derivatives: A Valid Pharmacophore in Medicinal Chemistry

AbstractOximes, belonging to imines with the general formula of RR'C=NOH, are produced by the nucleophilic addition reaction between hydroxylamine with ketones or aldehydes, yielding corresponding aldoxime and ketoxime. The presence of hydrogen bond acceptor and donor is the classical feature of oxime‐containing structural framework. This review presents a summary of the role of oximes and its structure activity relationships including antimicrobial, anticancer, anti‐inflammatory, antihyperglycemic, insecticidal agents, along with their involvement in the treatment of organophosphorus poisoning. The review also focused on the pharmacological profile of lead molecules of several classes of oxime‐containing compounds.