Influence Of Solvent Research Articles

Spin crossover FeIII complexes with a substituted Hqnal ligand: effects of anions and solvents.

A new substituted Hqnal ligand, Hqnal-5-Brq, and four resulting FeIII complexes [Fe(qnal-5-Brq)2]A·sol (A = NO3-, sol = CH3OH 1; A = ClO4-, sol = CH3OH 2; A = OTf-, sol = 2CH3OH·H2O 3; and A = NTf2-, sol = CH2Cl24; Hqnal-5-Brq = N-(5-bromo-8-quinolinyl)-2-hydroxynaphthaldimine), have been synthesized and characterized. All four complexes, despite having different anions, adopt similar 1D [Fe(qnal-5-Brq)2]+ cation chains linked by orthogonal π⋯π interactions. These chains are further connected to form 2D and 3D structures by other supramolecular interactions. Complexes 1-3 all exhibit abrupt spin crossover behaviors, with the transition temperatures being 230, 189, and 185 K, respectively, while complex 4 is in a high-spin state. The influence of solvents on spin crossover properties was assessed via magnetic measurements on the desolvated samples. Following desolvation, while complexes 1 and 2 show slight variations in their transition temperatures, complexes 3 and 4 undergo significant changes in their magnetic profiles. Desolvation in complex 3 leads to either a HS state or a very incomplete hysteretic transition with a low transition temperature for different sample batches. In contrast, the gradual desolvation in complex 4 leads to diminished solvent residues and progressive transition from a stable HS state to an SCO-active state.

Acrylate–methacrylate radical copolymerization kinetics of sparingly water-soluble monomers in polar and nonpolar solvents

The influence of solvent on radical copolymerization kinetics is studied to provide insight to emulsion polymerization systems.

Solvent-induced supramolecular self-assembly in a solid-state A1/A2-difunctionlized pillar[5]arene host

Herein we report the influence of the crystallization solvent in the supramolecular self-assembly in the solid-state of an A1/A2-difunctionlized pillar[5]arene host.

Spectroscopic and thermodynamic characterization of a cobalt-verdazyl valence tautomeric system. influence of crystal structure, solvent and counterion.

Crystallization of the verdazyl-based valence tautomeric ion [Co(dipyvd)2]2+ (where dipyvd is the radical ligand 1-isopropyl-3,5-di(2'-pyridyl)-6-oxoverdazyl) with a variety of different counterions results in materials that show varying degrees of valence tautomeric (VT) transition in the solid state. The X-ray structure of the SbF6 salt at 150 K reveals a localized structure for the S = 1/2 tautomer, with a Co3+ cation and distinct anionic and radical ligands. Comparison with the structure of the same material at 300 K reveals large structural changes in the ligand as a result of the valence tautomeric equilibrium. Data for the S = 3/2 form is less conclusive; X-ray spectroscopy on the PF6 salt suggests a degree of low spin Co2+ character for the S = 3/2 tautomer at very low temperature though this is inconsistent with EPR data at similar temperatures and structural information at 150 K. Magnetic measurements on the [BArF4]- and triflate salts in organic solvents show that the VT equilibrium is dependent on solvent and ion pairing effects.

Effect of Extracting Solvent on the Quality of Lentinula edodes Oil Based on Chemical Composition, in vitro Antioxidant Activity and Correlation Analysis.

In this study, effects of 4 solvents (petroleum-ether, n-hexane, ethyl-acetate, and chloroform) on the chemical characterizations and in vitro antioxidant capacities of oil were assessed to determine the optimal extraction solvent for L. edodes oil. Three data analysis techniques including principal component analysis, hierarchical cluster analysis, and multiple linear regression, were applied to determine the relationship between the nutrient and antioxidant capacity. The results showed that chloroform extracted L. edodes oil exhibited the largest amount of α-tocopherol, flavones, and unsaponifiable matter, chloroform was thus confirmed desirable for extracting L. edodes oil rich in nutrition. While based on the best DPPH and ABTS, the ethyl-acetate extracted oil show the strongest antioxidant property. More than that, the results also showed that different extraction solvents could induce large variations in minor components and free radical scavenging activity among the test oils, and the total phenol content was found positively correlated to the antioxidant capacity of L. edodes oil, which could be well predicted by all MLR models. These findings revealed the influence of solvent on the chemical characterization and in vitro antioxidant capacity of L. edodes oil, providing a theoretical foundation for future applications of L. edodes oil.

Conjugated microporous polymer frameworks for sustainable energy materials – elucidating the influence of solvents on the porosity properties for future design principles

Here, we use atomic simulations to rationalise why using high polarity solvents to synthesise conjugated microporous polymers gives a high ratio of micro- to mesoporosity, and using low polarity solvents gives a lower ratio of micro- to mesoporosity.

ANALYSIS OF DISSOLVING ABILITY OF LOWER ALCOHOLS AND ESTERS AQUEOUS AND HYDROCARBON SOLUTIONS TO ORGANIC MATTER OF BAZHENOV FORMATION ROCKS

This work is devoted to studying the characteristics of treatments with organic solvents on bazhenov formation rock samples, which contains a large amount of unconverted organic matter (kerogen, bitumen). This article contains the results of studying the dissolving abilities of individual low-molecular alcohols and esters, and solutions of these compounds in water and in a non-polar aromatic solvent (petroleum solvent). Among the individual solvents studied, esters of acetic acid showed the greatest dissolving ability; alcohols are less active. Petroleum solvent slightly dissolves the rock’s organic matter and needs the addition of more polar organic compounds. The dependences of dissolving ability of alcohols’ hydrocarbon solutions on alcohol concentration is extreme, with a maximum of 10 wt.%. Based on the obtained results, the mutual influence of solvents in the hydrocarbon fluid was additionally evaluated. It has been established that solutions of isopropanol and aromatic solvent show a synergistic effect to the dissolution of rock organic matter more than hydrocarbon solutions of esters. For the compositions that showed the greatest dissolving ability, a qualitative and semi-quantitative analysis was made for establishing changes in the composition of rock samples after extraction using X-Ray diffraction and Fourier-transform infrared spectroscopy. It is shown that mixtures of polar and non-polar solvents provide a more regular extraction of aliphatic and aromatic components of rock organic matter. Systems containing petroleum solvent, isopropanol and isopropyl acetate have been identified as the basis for the development of process fluids for increasing oil recovery in organic-rich reservoirs.

RATE AND SELECTIVITY OF HYDROGENATION OF 2-NITRO-2'-HYDROXY-5'-METHYLAZOBENZE OVER NICKEL CATALYST IN AQUEOUS SOLUTIONS OF ALIPHATIC ALCOHOLS

Elucidation of the causes and character of the composition and nature solvent influence on the kinetic regularities and selectivity of hydrogenation reactions of compounds containing several reactive groups is of theoretical and practical significance. In the present work, the process of 2-nitro-2'-hydroxy-5'-methylazobenzene catalytic hydrogenation in the liquid phase is considered in order to obtain the corresponding benzotriazole, an effective UV stabilizer of polymeric materials. The process was carried out on a skeletal nickel catalyst in aqueous solutions with different contents of aliphatic alcohols, both at atmospheric and elevated hydrogen pressures. It has been experimentally established that the shape of the hydrogenation kinetic curves is determined by the composition of the water-alcohol solvent and is transformed from the dependence with a maximum in media with low alcohol content to the stepped curve in concentrated solutions. The dependences of the reaction rate on the content of aliphatic alcohol are complex, and the maximum hydrogenation rates are observed in solvents with a content 0.6÷0.7 ppm. of alcohol. The change in the process rate is associated with a change in the solubility, value of adsorption and reactivity of the starting compound and hydrogen. These factors also determine the selectivity of the process due to their influence on the rates of individual steps in the 2-nitro-2'-hydroxy-5'-methylazobenzene conversion scheme, in particular, on the cyclization rate of the associative surface complex "nitroazobenzene∙H2". The cyclization product of the complex is an intermediate compound, benzotriazole N-oxide, the reduction of which leads to the formation of a substituted benzotriazole. It is shown that the maximum yield of the target product is 48÷3% at atmospheric hydrogen pressure, and increases to 73.5-0.5% at PН2 = 1 MPa.

Dendritic ZSM-5 zeolites as highly active catalysts for the valorization of monoterpene epoxides.

Dendritic ZSM-5 zeolites were investigated in the isomerization of monoterpene epoxides, including limonene-1,2-epoxide (LE), α-pinene epoxide, and β-pinene epoxide, which yields high-value compounds used in fragrances, cosmetics, and pharmaceuticals. The fresh catalysts were thoroughly characterized using XRD, Ar physisorption, pyridine-FTIR, TEM, FTIR/DTBPyr, and 27Al MAS NMR. In comparison with conventional and hierarchical ZSM-5 materials, the dendritic zeolite with a crystallization time of 4 days (d-ZSM-5/4d) was the most active material, with a turnover frequency value of 4.4 min-1 for LE isomerization. Likewise, remarkable yields of dihydrocarvone (DHC, 63%, 70 °C, 2 h), campholenic aldehyde (72.4%, 70 °C, 5 min), and myrtanal (47.7%, 50 °C, 5 min) were obtained with this material that exhibited the largest mesopore/external surface area (360 m2 g-1), showing also the narrowest mesopore size distribution. A direct relationship was observed between the TOF values and the concentration of external Brønsted acid sites, showing the presence of strong steric/diffusional limitations that are greatly overcome with the dendritic zeolites. The lower reactivity of trans-LE compared to cis-LE was attributed to the larger steric hindrance of the oxygen atom. Exploration of the solvent influence revealed that the reaction rate of LE was favored by non-polar solvents, while highly selective DHC formation occurred in the solvents of medium polarity. The d-ZSM-5/4d sample was shown to be robust because catalytic activity could be completely recovered by air calcination.

The influence of the polyol solvents on the continuous growth of water-dispersible iron oxide nanoparticles

Magnetic nanoparticles have continued to gain significant attention due to their unique magnetic properties and potential applications. However, it is still challenging to directly synthesize water-dispersible magnetic nanoparticles with controlled size for biomedical applications. This study investigates the influence of solvents on the continuous growth of magnetic nanoparticles, aiming to achieve controlled size and excellent water dispersibility via thermal decomposition in polyol solvents. The size of the nanoparticles gradually increases with longer polyol chain solvents. The increase in nanoparticles size is more significant under a higher reaction temperature (220 °C) compared to a lower temperature (190 °C). These monodispersed nanoparticles exhibit strong superparamagnetic properties, improving with longer solvent chain lengths at the same size. Magnetic resonance imaging (MRI) studies reveal higher relaxivities for magnetic nanoparticles synthesized in longer-chain polyols. This research offers valuable insights for synthesizing magnetic nanoparticles with precise sizes, magnetic properties, and biomedical applications.Graphical abstract

Green next-generation excipients enriched in polyphenols from recovery of grape processing waste black bentonite: Influence of unconventional extraction solvents on antioxidant properties and composition.

According to the UN Agenda 2030, several actions could be taken to act synergistically towards various areas of critical importance for both the humanity and the planet. Among them, the application of a circular economy model based on the valorisation of the wastes from the local resources could be a virtuous attitude. In this view, this work proposes a dual green approach for recovery of the waste black bentonite from the fining of organic white grape must. Indeed, this virtuous recovery idea is enhanced by the choice of both eco-friendly extraction method (maceration) and solvents. The latter were unconventional solvents selected among the pharmaceutic/cosmetic liquid hydrophilic excipients (waste-to-market approach) characterized by safety and high solvent power toward polyphenols. PEGs (200, 400, 600), Propylene Glycol and Glycerol were tested and the extracted compared by HPLC-DAD analyses as well as the Folin-Ciocalteu, DPPH and Bradford assays. PEG200 emerged as the best one, leading to coloured extract containing great amount of polyphenols (3.123 ± 0.106 mg/g) and specifically Quercetin (60.778 ± 2.307 μg/mL), which confer it interesting scavenger properties, potentially making it directly useful in a wide range of fields from the pharmaceutic to the cosmetic ones.

Molecular Wind-Up Meter for the Quantification of London Dispersion Interactions.

ConspectusThe experimental quantification of interactions on the molecular level provides the necessary basis for the design of functional materials and chemical processes. The interplay of multiple parameters and the small quantity of individual interactions pose a special challenge for such endeavors. The common method is the use of molecular balances, which can exist in two different states. Thereby, a stabilizing interaction can occur in one of the states, favoring its formation and thus affecting the thermodynamic equilibrium of the system. One challenge is determining the change in this equilibrium since various analytical methods could not be applied to fast-changing equilibria. A new and promising method for quantifying molecular interactions is the use of Molecular Wind-up Meters (MWM) in which the change in kinetics, rather than the effect on thermodynamics, is investigated. An MWM is transformed with an energy input (e.g. irradiation) into a metastable state. Then, the rate of thermal transformation back to the ground state is measured. The strength of interactions present in the metastable state controls the kinetics of the back reactions, allowing direct correlation. The advantage of this approach lies in the high sensitivity (energy differences can be larger by 1 order of magnitude) and, in general, allows the use of a broader range of solvents and analytical methods. An Azobenzene-based MWM has been established as a powerful tool to quantify London dispersion interactions. London dispersion (LD) represents the attractive part of the van der Waals potential. Although neglected in the past due to its weak character, it has been shown that the influence of LD on the structure, stability, and reactivity of matter can be decisive. Especially in larger molecules, its energy contribution increases overproportionately with the number of atoms, which has sparked increasing interest in the use of so-called dispersion energy donors (DED) as a new structural element. Application of the azobenzene-based MWM not only allowed the differentiation of bulkiness, but also systematically addressed the influence of the length of n-alkyl chains. Additionally, the solvent influence on LD was studied. Based on the azobenzene MWM, an increment system has been proposed, allowing a rough estimate of the effect of a specific DED.

Solvatochromic shifts and solvent effects on the electronic and transport behaviour of 1-Chloro Adamantane

Solvent influence on the photophysical and electronic properties of 1-Chloro Adamantane (CAD) are investigated using experimental and computational methods. Measured UV–vis absorption of CAD in various solvents exhibits substantial solvatochromatic shifts with respect to the solvent polarity. As a result of this, optical absorption of CAD undergoes the bathochromic shifts in the nonpolar solvents and hypsochromic shifts in the polar solvents with respect to polarity. Theoretical computations of EOM-CCSD and CIS quantum chemical methods calculated by means of SMD solvation model demonstrate the solvent influence on the electronic structure of CAD which are in good agreement with the experimental results. Computed results show prominent solvation effect on Lewis and non-Lewis occupancies. Large excited state dipole moment of the CAD in various solvation suggests excited states are more polarized than the ground state. In addition to this, molecular polarizabilities and energies of HOMO and LUMO show dominant solvent effects on the chemical reactivity of the CAD upon solvation. This solvent specific behaviour of CAD finds applications in optical filters with its significant hydrophobic nature.

Mechanism of deep eutectic solvent-mediated microalgal biomass disintegration for enhanced lutein extraction

Microalgae as a source of natural lutein get increasing attention since they feature a high quantity and quality of this pigment. Recalcitrance of the microalgal cell wall declines the bioaccessibility, bioavailability, and digestibility of the beneficial compounds contained in the microalgae. This study aimed to evaluate the influence of deep eutectic solvent (DES) based approaches for the disintegration of Chlorella pyrenoidosa cells for lutein recovery and explore the underlying mechanism. The results showed that choline chloride-ethylene glycol DES (ChCl:EG 1:2) achieved a better cell disintegration and lutein stability than other DESs. Molecular dynamics simulations revealed that chloride anion (Cl−) dominated the dissolution of cellulose for breaking down cell wall structure of C. pyrenoidosa. Solvent screening and process optimization resulted in 239.92 mg/100 g lutein yield with ethanol solvent under optimized condition. Disintegration significantly increased the release of lutein from microalgae. This study provided the theoretical guidance and experimental prove of improve lutein extraction from microalgal biomass in a green and sustainable extraction procedure.

Mesenchymal stem cells aligned and stretched in self-assembling peptide hydrogels

The presented research highlights a novel approach using fmoc-protected peptide hydrogels for the encapsulation and stretching of mesenchymal stem cells (MSCs). This study utilized a custom mechanical stretching device with a PDMS chamber to stretch human MSCs encapsulated in Fmoc hydrogels. The study assessed the influence of various solvents on the self-assembly and mechanical properties of the hydrogels, and MSC viability and alignment. Particularly we focused on fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF) prepared in dimethyl sulfoxide (DMSO), hexafluoro-2-propanol (HFP), and deionized water (DiH2O).Through molecular self-assembly of the peptide sequence into β-sheets connected by π-π aromatic stacking of F–F groups, the peptide hydrogel was found to form a stiff, hydrated gel with nanofiber morphology and a compressive modulus ranging from 174 to 277 Pa. Therefore, this hydrogel can mimic certain critical features of the extracellular matrix and collagen. Evaluations of MSCs cultured on the peptide hydrogels, including viability, morphology, and alignment assessments using various staining techniques, demonstrated that 3D-cultured MSCs in Fmoc-FF/HFP and Fmoc-FF/DMSO, followed by mechanical stretching, exhibited elongated morphology with distinct microfilament fibers compared to the control cells, which maintained a round and spherical F-actin shape. Notably, peptide gels with a concentration of 5 mM maintained 100 % MSC viability.The findings indicate the potential and specific conditions for successful cell encapsulation and alignment within peptide hydrogels, highlighting a promising tissue engineering platform through the encapsulation of MSCs in peptide nanofibers followed by a stretching process. By enhancing our understanding of MSC-peptide hydrogel interactions, this research contributes to the development of biomaterials tailored for regenerative medicine.

One-pot aerobic conversion of fructose to 2,5-diformylfuran using silver-decorated carbon materials

The synthesis of 2,5-diformylfuran (DFF) from fructose is a simultaneous process using two distinct catalysts, including fructose dehydration to 5-hydroxymethylfurfural (5-HMF) accelerated by an acid catalyst, followed by 5-HMF oxidation to DFF mediated by a redox catalyst. In this study, various catalysts with Ag metal decorated on sulfonated amorphous carbon supports (AC-SO3H@Ag) were performed, and their structures were characterized via different characterization techniques such as X-ray diffraction, scanning electron microscopy, X-ray fluorescence spectroscopy, thermogravimetric analysis, Boehm's titration, inductively coupled plasma mass spectroscopy, energy-dispersive X-ray spectroscopy, elemental mapping analysis and Fourier-transform infrared spectroscopy. The catalytic performance of the prepared AC-SO3H@Ag bifunctional catalysts with various wt% of Ag/AC-SO3H was determined for the one-pot transformation of fructose into DFF. The influence of solvent, substrates, reaction time, and catalyst loading were also examined thoroughly to optimize the reaction, and a mechanism was proposed. 5-HMF formed by the dehydration of fructose was converted entirely to DFF, and the highest DFF yield of 77.9 % was obtained after 18 h of reaction time at 150 °C in dimethyl sulfoxide with 3 wt% of the AC-SO3H@Ag catalyst and without the use of any additives, traditional hydrogen acceptors, or oxidants. The reusability of the catalysts was also tested.

Phytochemical screening and biological evaluation of Greek sage (Salvia fruticosa Mill.) extracts

This study explores the influence of extraction solvents on the composition and bioactivity of Salvia fruticosa extracts. Ultrasound-assisted extraction with water, ethanol and their mixtures in variable proportions was used to produce four different extracts. An untargeted UPLC/MS‑based metabolomics was performed to discover metabolites profile variation between the extracts. In the analyzed samples, 2704 features had been detected, of which 95 were tentatively identified. The concentrations of the important metabolites, namely, caffeic acid, carnosic acid, carnosol, rosmarinic acid, salvianolic acid B and scutellarin, were determined, using UPLC-PDA methods. Rosmarinic acid was the dominant metabolite and antioxidant in all tested extracts, except the aqueous extract, in which scutellarin was the most abundant compound. The extracts and standards were examined for antioxidant activity and xanthine oxidase (XO) inhibitory activity. The most diverse in terms of chemical composition and rich in antioxidant compounds was 70% ethanolic extract and the strongest antioxidant was caffeic acid. All analyzed extracts showed the ability to inhibit XO activity, but the highest value was recorded for 30% ethanolic extract. Among tested standards, the most potent XO inhibitor was caffeic acid. The results suggest that the leaves of Greek sage are a source of natural XO inhibitors and may be an alternative to drugs produced by chemical synthesis.

Homogeneous Equilibrium in Solutions with Limited Solubility of Components

The equilibrium position of a homogeneous reversible chemical reaction in solutions in the case when at least one component is of limited solubility in the reaction mixture differs from the state when all components are unlimitedly soluble. Calculations of the minimum Gibbs energy in the model of extremely dilute solutions, according to Le Chatelier’s principle allow formulating the rule: if all other things being equal and unaltered, an increase in the solubility of a component in the reaction mixture shifts the position of homogeneous equilibrium towards an increase in its content. The results obtained can be generalized to the kinetics of reactions in terms of the influence of solvents. The theoretical foundations of a new lever for optimization of chemical processes were developed.

On the influence of solvent on the stereoselectivity of glycosylation reactions

Methodology development in carbohydrate chemistry entails the stereoselective formation of C–O bonds as a key step in the synthesis of oligo- and polysaccharides. The anomeric selectivity of a glycosylation reaction is affected by a multitude of parameters, such as the nature of the donor and acceptor, activator/promotor system, temperature and solvent. The influence of different solvents on the stereoselective outcome of glycosylation reactions employing thioglucopyranosides as glycosyl donors with a non-participating protecting group at position 2 has been studied. A large change in selectivity as a function of solvent was observed and a correlation between selectivity and the Kamlet-Taft solvent parameter π* was found. Furthermore, molecular modeling using density functional theory methodology was conducted to decipher the role of the solvent and possible reaction pathways were investigated.

Solubility measurements, correlation, and thermodynamic characterization of 4-guanidinobenzoic acid hydrochloride in pure and binary solvents from 294.55 K to 333.65 K

The solubility of 4-guanidinobenzoic acid hydrochloride (4-GABCL) in pure solvents (H2O, methanol, ethanol, n-propanol, isopropanol, 1-butanol, and 1-pentanol) and two binary solvents (H2O + ethanol/isopropanol) were determined by the dynamic saturation method in the temperature range of 294.55 K–333.65 K under atmospheric pressure. From the measurement results, it could be observed that the solubility of 4-GABCL in both pure and binary solvents all increased with increasing temperature. The solubility order of 4-GABCL in pure solvents was ranked as follows: methanol > H2O > n-propanol > ethanol > n-butanol > isopropanol > n-pentanol. The solubility of 4-GABCL in binary solvents tended to increase and then decrease with increasing molar fractions of ethanol and isopropanol, and the solubility of the solute in the binary solvents was greater than that of each in the monosolvents. In addition, Ideal model, Apelblat model, λh model, Wilson model, and NRTL model had been used to correlate the solubility of 4-GABCL in pure and binary solvents. Correlated effects show that the Wilson model gives the best correlation. The influence of solvents on the solubility of 4-GABCL was further studied by KAT-LSER model. The results showed that the solubility was mainly affected by the polarizability and the self-viscosity of the solvent.The mixing and dissolution thermodynamic properties of 4-GABCL in all experimental solvents had been calculated and analyzed by using the Wilson equation and solvent data. It was determined that the mixing and dissolution of 4-GABCL were spontaneous, endothermic and entropy-driven in the study systems. Besides, the solubility order of the pure solvent is consistent with the dissolution entropy at a temperature of 318.15 k.