Sulfoxide Mixtures Research Articles

Key Roles of Free Cations in Modulating the Reaction Rate in Imidazolium Ionic Liquid-Dimethyl Sulfoxide Mixtures.

Imidazolium ionic liquids (ILs) are widely utilized in various fields due to their distinctive properties. However, their high viscosity limits their application in specific reactions, and mixing ILs with organic components is a way to solve this problem. While previous studies mainly focused on the structural changes of ILs after adding organic molecules, no studies elucidated the influence of their existing species on chemical reactions. In this study, aerobic α-hydroxylation of 2-methylcyclohexanone was chosen as a model reaction, and the reaction rate was found to be adjusted by varying imidazolium concentration in its mixtures with dimethyl sulfoxide. To elucidate the mechanism, the distribution of species in an IL solution and its change with concentration were studied by molecular dynamics simulations, and the results revealed the significant impact of the concentration of free cations on the reaction rate. The interaction between the ionic species and reaction intermediate, as calculated by density functional theory, highlighted the crucial role of free cations in this reaction. This study demonstrates the feasibility of tuning the concentration of free cations by varying the concentration of the IL solution, establishing the relationship between its microstructure and chemical reaction efficiency, thus providing vital information for the design and application of ILs.

Chromo-fluorogenic detection of Sarin, Tabun, and mustard gas mimics triggering the ring-opening reaction in a spirolactam-based probe

Nerve agents are becoming serious issues for the healthy and sustainable environment in modern civilization. Strategically, we have designed and introduced a Schiff base triggered dual chromo-fluorogenic probe BASO via condensation reaction between rhodamine B hydrazide and 3-formyl chromone, which can selectively recognize different toxic target analytes helping a reference to a healthy and sustainable environment. The BASO probe displays enhanced pink photoluminescence extraordinarily due to the introduction of sarin, tabun, and mustard gas mimics diethylchlorophosphate (DCP), diethylcyanophosphonate (DCNP), and 2-chloroethyl ethyl sulfide (2CEES), in a 1:1 water–dimethyl sulfoxide (DMSO) mixture while native one was non-fluorescent. The opening of the spirolactam ring owing to the addition of DCP, DCNP, and 2CEES shows a noticeable pink colorimetric and pink color fluorometric change, which is readily detectable by the naked eye in the µM range in neutral medium and found to be better than numerous available chemosensor (Table S1). We have also fabricated simple paper strip-based test kits as portable and displayable handy photonic tools for on-site detection without any expensive instrumental techniques. The probe BASO has also been employed for detecting the vapor phase and soil sample analysis as a practical applicability. The simple, rapid detection techniques make our probe unique and have significant utility for the recognition of DCP, DCNP, and vesicant or blistering agents mimicking 2CEES.

Retinoic acid reduces kidney injury by regulating oxidative stress, NRF-2, and apoptosis in hyperoxic mice.

Nuclear factor-erythroid-2-related factor-2 (NRF-2) is a cellular resistance protein to oxidants. We investigated the effect of exogenous all-trans retinoic acid (ATRA) on the antioxidant system and NRF-2 in mice kidneys under hyperoxia-induced oxidative stress. Mice were divided into four groups. Daily, two groups were given either peanut-oil/dimethyl sulfoxide (PoDMSO) mixture or 50 mg/kg ATRA. Oxidative stress was induced by hyperoxia in the remaining groups. They were treated with PoDMSO or ATRA as described above, following hyperoxia (100% oxygen) for 72 h. NRF-2 and active-caspase-3 levels, lipid peroxidation (LPO), activities of antioxidant enzymes, xanthine oxidase (XO), paraoxonase1 (PON1), lactate dehydrogenase (LDH), tissue factor (TF), and prolidase were assayed in kidneys. Hyperoxia causes kidney damage induced by oxidative stress and apoptosis. Increased LPO, LDH, TF, and XO activities and decreased PON1 and prolidase activities contributed to kidney damage in hyperoxic mice. After hyperoxia, increases in the activities of antioxidant enzymes and NRF-2 level could not prevent this damage. ATRA attenuated damage via its oxidative stress-lowering effect. The decreased LDH and TF activities increased PON1 and prolidase activities, and normalized antioxidant statuses are indicators of the positive effects of ATRA. We recommend that ATRA can be used as a renoprotective agent against oxidative stress induced-kidney damage.

In vitro toxicity evaluation in A549 cells of diesel particulate matter from two different particle sampling systems and several resuspension media.

In urban areas, inhalation of fine particles from combustion sources such as diesel engines causes adverse health effects. For toxicity testing, a substantial amount of particulate matter (PM) is needed. Conventional sampling involves collection of PM onto substrates by filtration or inertial impaction. A major drawback to those methodologies is that the extraction process can modify the collected particles and alter their chemical composition. Moreover, prior to toxicity testing, PM samples need to be resuspended, which can alter the PM sample even further. Lastly, the choice of the resuspension medium may also impact the detected toxicological responses. In this study, we compared the toxicity profile of PM obtained from two alternative sampling systems, using in vitro toxicity assays. One system makes use of condensational growth before collection in water in an impinger - BioSampler (CG-BioSampler), and the other, a Dekati® Gravimetric Impactor (DGI), is based on inertial impaction. In addition, various methods for resuspension of DGI collected PM were compared. Tested endpoints included cytotoxicity, formation of cellular reactive oxygen species, and genotoxicity. The alternative collection and suspension methods affected different toxicological endpoints. The water/dimethyl sulfoxide mixture and cell culture medium resuspended particles, along with the CG-BioSampler sample, produced the strongest responses. The water resuspended sample from the DGI appeared least toxic. CG-BioSampler collected PM caused a clear increased response in apoptotic cell death. We conclude that the CG-BioSampler PM sampler is a promising alternative to inertial impaction sampling.

Viscosity Measurement of CO2-Solvent Mixtures for the Study of the Morphology and Size of Crystalline Particles Obtained Using Supercritical Antisolvent Precipitation.

The viscosity values of CO2-dimethylphormamide, chloroform, methanol, isopropanol, ethyl acetate, acetone, and dimethyl sulfoxide mixtures were measured at a pressure of 150 bar and a temperature of 313 K. The correlation of the mean size of levofloxacin hydrochloride and malonic acid particles precipitated using the SAS method with the viscosity of the used CO2-solvent mixtures is shown. The high viscosity of the mixtures leads to slower mixing of the solution and the antisolvent. Therefore, crystallization occurs at large fractions of the solvent, and as a consequence at a lower supersaturation. This causes the formation of larger particles when using more viscous solvents in SAS.

Biochemical characterization of GAF domain of free-R-methionine sulfoxide reductase from Trypanosoma cruzi

Trypanosoma cruzi is the causal agent of Chagas Disease and is a unicellular parasite that infects a wide variety of mammalian hosts. The parasite exhibits auxotrophy by L-Met; consequently, it must be acquired from the extracellular environment of the host, either mammalian or invertebrate. Methionine (Met) oxidation produces a racemic mixture (R and S forms) of methionine sulfoxide (MetSO). Reduction of L-MetSO (free or protein-bound) to L-Met is catalyzed by methionine sulfoxide reductases (MSRs). Bioinformatics analyses identified the coding sequence for a free-R-MSR (fRMSR) enzyme in the genome of T. cruzi Dm28c. Structurally, this enzyme is a modular protein with a putative N-terminal GAF domain linked to a C-terminal TIP41 motif. We performed detailed biochemical and kinetic characterization of the GAF domain of fRMSR in combination with mutant versions of specific cysteine residues, namely, Cys12, Cys98, Cys108, and Cys132. The isolated recombinant GAF domain and full-length fRMSR exhibited specific catalytic activity for the reduction of free L-Met(R)SO (non-protein bound), using tryparedoxins as reducing partners. We demonstrated that this process involves two Cys residues, Cys98 and Cys132. Cys132 is the essential catalytic residue on which a sulfenic acid intermediate is formed. Cys98 is the resolutive Cys, which forms a disulfide bond with Cys132 as a catalytic step. Overall, our results provide new insights into redox metabolism in T. cruzi, contributing to previous knowledge of L-Met metabolism in this parasite.

Effect of the Polarity of Solvents on Periodic Precipitation: Formation of Hierarchical Revert Liesegang Patterns.

Liesegang pattern (LP) is one example of self-organized periodic precipitation patterns in nonequilibrium systems. Several studies have demonstrated that the LP morphology can track physicochemical environmental conditions (e.g., temperature); however, the polarity effect has not been explored to date. In this study, a copper chromate system is used to reveal the impact of solvent polarity on the evolving LP structure using water/organic solvent mixtures. In the typical case of using water/dimethyl sulfoxide (DMSO) mixtures, two drastic changes in LP morphology with increasing DMSO contents were found: (i) increasing frequency of the original structure and (ii) formation of a hierarchical pattern with the appearance of another, lower-frequency structure. Furthermore, the simulation model operating with a bimodal size distribution, allowing both homogeneous and heterogeneous precipitations showed good agreement with the experimental results. Therefore, this study demonstrated that LP can be tailored by solvent polarity and can be used for designing hierarchical precipitation patterns in a straightforward manner.

Mixtures of Diethyl Sulfoxide and Methanol: Structure and Thermodynamics

Mixtures of sulfoxides with molecular solvents possess interesting physicochemical properties and may have applications in chemical synthesis. Hereby we confirm and rationalize the previously reported excellent miscibility of diethyl sulfoxide (DESO) with methanol (MeOH). By performing a comprehensive potential energy surface investigation we identified a global minimum for each system and a significant number of local minima described at the hybrid density functional level of theory. A strong 0.18 nm long hydrogen bond forming between the oxygen atom of DESO and the polarized hydrogen atom of MeOH was evidenced both via the structural and spectral analyses. Our results robustly explain negative deviations in the DESO–MeOH mixtures from ideal behavior and interpret the experimental observations with microscopic precision.Graphical Abstract

Effect of high hydrostatic pressure treatment with room-temperature ionic liquid 1-ethyl-3-methylimidazolium acetate - dimethyl sulfoxide mixture on lipid extraction from Chlorella vulgaris

ABSTRACT In this study, Chlorella vulgaris (C. vulgaris) was immersed in a mixture of 1-ethyl-3-methylimidazolium acetate and dimethyl sulfoxide, and treated hydrostatically at 0.1-250 MPa. For the first time, the relationship between the amount of lipids and fatty acids and high hydrostatic pressure was investigated, as well as the relationship between the amount of fatty acids and the morphology of C. vulgaris cells after treatment. We found that the amount of lipids was maximized and the amount of fatty acids extracted was significantly higher following treatment at 50 MPa than at ambient pressure. The purity of the extracted fatty acids (the amount of fatty acids contained in the extracted lipids) was high following treatment at 200 and 250 MPa, and was about double that of the amount of fatty acids obtained using the Bligh & Dyer and Soxhlet extraction methods, which are typically used for lipid extraction.

Directed evolution of unspecific peroxygenase in organic solvents.

Fungal unspecific peroxygenases (UPOs) are efficient biocatalysts that insert oxygen atoms into nonactivated C-H bonds with high selectivity. Many oxyfunctionalization reactions catalyzed by UPOs are favored in organic solvents, a milieu in which their enzymatic activity is drastically reduced. Using as departure point the UPO secretion mutant from Agrocybe aegerita (PaDa-I variant), in the current study we have improved its activity in organic solvents by directed evolution. Mutant libraries constructed by random mutagenesis and in vivo DNAshuffling were screened in the presence of increasing concentrations of organic solvents that differed both in regard to their chemical nature and polarity. In addition, a palette of neutral mutations generated by genetic drift that improved activity in organic solvents was evaluated by site directed recombination in vivo. The final UPO variant of this evolutionary campaign carried nine mutations that enhanced its activity in the presence of 30% acetonitrile (vol/vol) up to 23-fold over PaDa-I parental type, and it was also active and stable in aqueous acetone, methanol and dimethyl sulfoxide mixtures. These mutations, which are located at the surface of the protein and in the heme channel, seemingly helped to protect UPO from harmful effects of cosolvents by modifying interactions with surrounding residues and influencing critical loops.

Acoustical Studies& Molecular Interactions of Antiepileptic Drug Levitiracetam in DMSO-Water Mixtures at Different Temperatures

The densities and speeds of sound have been measured of ternary mixtures of Levitiracetam drug in aqueous dimethyl sulfoxide (DMSO) mixtures at 25% interval of the solvent at 303K,308 K,313 K and frequency 2MHz .The experimental data has been used to determine acoustic parameters like intermolecular free length (Lf),Specific acoustic impedence (z) etc.The changes in these properties with composition and temperature are used to interpret the nature of solute-solvent, solute-solute interactions in the system.

Education for Sustainable Development: An Undergraduate Chemistry Project on Cellulose Dissolution, Regeneration, and Chemical Recycling of Polycotton

We introduced an undergraduate chemistry project within the framework of education for sustainable development (ESD). The objective of the first part was to demonstrate the efficiency of an ionic liquid (IL)- 1-(n-butyl)-3-methylimidazolium acetate (BuMeImAcO)- as solvent for the dissolution, and subsequent regeneration of cellulose as fiber. Under mechanical stirring, the students dissolved microcrystalline cellulose in a mixture of BuMeImAcO-dimethyl sulfoxide (DMSO) at 80°C. Subsequently, they dyed the dissolved cellulose with a reactive dye, and regenerated (pink) colored fibers by injecting the resulting biopolymer solution into water (a non-solvent for cellulose). The objective of the second experiment was to show the potential application of BuMeImAcO-DMSO for the chemical recycling of the cellulosic component of polycotton (cellulose: polyethylene terephthalate; PET). Cellulose dissolves under the above-mentioned experimental conditions, leaving a mat of PET. The students dyed the dissolved cellulose, and then regenerated the biopolymer as fiber. This project fits the following aspects of ESD: fiber production from renewable sources other than cotton (wood-based cellulose); recycling of cellulose from its blends with synthetic polymers, when their reuse is not feasible. We recommend this project for senior science students of, e.g., chemistry, engineering and pharmacy, because of its simplicity, safety and socioeconomic relevance.

Regenerated Cellulose Fibers Wetspun from Different Waste Cellulose Types

ABSTRACT Regenerated cellulosic fibers were successfully spun from various waste cellulose sources (cotton linter, bagasse, and cardboard) suitable for use as a textile fibers using a wet spinning process with an ionic liquid/dimethyl sulfoxide (IL/DMSO) mixture as the solvent. The solubility of the waste cellulose sources in IL/DMSO varies according to the source of the raw material. Regenerated fibers can be spun from all the waste feedstock, the spinnability and fiber tensile strength is governed by the DP and chemical composition of the cellulose. The structural properties of the spun fibers are determined by x-ray diffraction, thermalgravimetric analysis, and scanning electron microscope. The results reveal that the properties of the starting materials and thus how the waste feed streams are pretreated have a significant impact on the mechanical properties, crystallite structure, thermal stability, and the morphology of the fibers.

A cryopreservable cell-laden GelMa-based scaffold fabricated using a 3D printing process supplemented with an in situ photo-crosslinking

Scaffolds consisting of cylindrical struts are one of the high-potential tissue engineering materials because the highly porous structure can easily induce cell infiltration/migration and efficiently deliver nutrients to the cells. In addition, cryopreservable scaffolds have attracted much interest in tissue engineering because they can be prospective ready-to-use “living” biomaterials consisting of a patient’s own cells. In this study, we investigated a cryopreservable cell-printed scaffold consisting of microscale cylindrical struts. To fabricate the scaffold, we developed a 3D cell-printing system supplemented with microfluidic channels, a core-shell nozzle, UV treatment system, and low-temperature working plate. The scaffold consisted of a cell-laden collagen/dimethyl sulfoxide (DMSO) mixture in the core region and a methacrylate gelatin (GelMA)/DMSO mixture in the shell region. After cryopreservation, the preosteoblasts (MC3T3-E1) loaded in the scaffold showed reasonable cell viability (∼85%). Moreover, no significant difference was observed in the cell proliferations and ALP activities of the cryopreserved scaffold and non-cryopreserved scaffold. Based on these results, we believe that the fabrication process can be one of the potential techniques for fabricating cryopreservable scaffolds consisting of cylindrical struts.

Role of nuclear factor-erythroid 2-related factor 2 in diabetic rats with resveratrol preconditioning against myocardial isch- emia-reperfusion injury

Objective To observe the effect of nuclear factor-erythroid 2-related factor 2 (Nrf2) in diabetic rats preconditioning with resveratrol (Res) against myocardial ischemia/reperfusion injury (MI/RI). Methods Healthy adult male SD rats weighing 200- 220 g and aged from 4 to 5 months were fed with high-fat diet for 4 weeks and then intraperitoneally injected with streptozotocin (STZ) 30 mg/kg to establish a diabetic rat model. Thirty successfully modeled rats were divided into three groups according to a random number table (n=10): a sham operation group (a Sham group), a myocardial ischemia/reperfusion group (an MI/R group) and a myocardial ischemia/reperfusion+resveratrol group (an MI/R+Res group). A rat model of MI/RI was established by ligation of the left anterior descending coronary artery for 30 min before reperfusion for 120 min. In the MI/R+Res group, 15 mg/kg Res was intraperitoneally injected 7 d before establishment of the MI/RI model, once a day for 7 consecutive days. The Sham and MI/R groups were intraperitoneally injected with an equal volume of dimethyl sulfoxide (DMSO) and PBS mixture. Left ventricular ejection fraction (LVEF) and left ventricular short axis shortening (FS) were measured by B-mode ultrasonography. Five rats were sacrificed 120 min after reperfusion. Myocardial infarction size was measured by 2, 3, 5-triphenyl-2H-tetrazolium chloride (TTC) staining. Another five rats were sacrificed to collect blood samples from the abdominal aorta for measurement of lactate dehydrogenase (LDH), a marker of myocardial injury, and creatine kinase isoenzyme (CK-MB). Their myocardial tissues were collected to determine the levels of superoxide dismutase(SOD), malondialdehyde (MDA) and reactive oxygen species (ROS) by enzyme-linked immunosorbent assay (ELISA). The contents of Nrf2 were observed by immunohistochemistry. The expression of Nrf2, n-Nrf2 and heme oxygenase-1 (HO-1) were determined by Western blot. Results Compared with those in the Sham group, LDH, CK-MB concentration, ROS and MDA content in the MI/R and MI/R+ Res groups significantly increased while LVEF, FS, and SOD activity in the MI/R and MI/R+Res groups significantly decreased. Mean-while, the myocardial infarction sizes in the MI/R and MI/R+Res groups were increased, and the expression of Nrf2, n-Nrf2 and HO-1 protein was down-regulated (all P<0.05). Compared with those in the MI/R group, LDH, CK-MB concentration, ROS and MDA content significantly decreased in the MI/R+Res group, while LVEF, FS and SOD activity significantly increased in the MI/R+Res group. Also, in the MI/R+Res group, the myocardial infarction size decreased while the expression of Nrf2, n-Nrf2 and HO-1 protein increased (all P< 0.05). Conclusions Resveratrol preconditioning relieves myocardial injury in diabetic rats with ischemia/reperfusion, which may attribute to activation of Nrf2. Key words: Resveratrol; Transcription factor-related factor 2; Heme oxygenase-1; Diabetes; Myocardial ischemia/reperfusion

Simple treatment of cell culture surfaces with water-dimethyl sulfoxide mixtures impacts YAP localization in vascular endothelial cells

Subcellular localization of yes associated proteins (YAPs) plays a critical role in endothelial cell proliferation. Since the surface properties of cell culture materials are known to affect the subcellular localization of YAPs, there are high expectations that cellular functions could be manipulated by materials-designing. In the present study, we demonstrated that surface treatment of tissue culture polystyrene (TCPS) substrates with a mixture of water and dimethyl sulfoxide (DMSO) affects the proliferation of endothelial cells. We found that surfaces treated with a mixture containing a higher DMSO ratio became more hydrophobic, while surfaces treated with a low DMSO ratio caused YAP to translocate to the nucleus and promote cell proliferation. Thus, we propose that surface treatment of TCPS with water and DMSO could be a simple way to manipulate specific cellular functions.

Investigation of hydrogen bonding in Water/DMSO binary mixtures by Raman spectroscopy.

Raman spectra of water/dimethyl sulfoxide (DMSO) mixtures have been observed at room temperature and atmospheric pressure. We find that the Raman peaks corresponding to the symmetric and asymmetric O-H stretching vibration mode of water rapidly move to lower wavenumber with increasing DMSO concentration. These results indicate that the strong hydrogen bond between DMSO-water complexes helps to strengthen the tetrahedral structure of water when the volume fraction of DMSO is less than 0.6. Moreover, the blue/red shifts of SO and C-H are obvious when the concentration of DMSO reaches 0.6, which may be due to changes in the structure of the DMSO-water complex. Furthermore, the frequency shift of the C-H group indicates that the non-polar methyl group of DMSO forms a hydrophobic hydrated structure. Finally, the frequency shift of the Raman peaks of SO and C-H exhibited a highly consistent concentration dependence due to the cooperation effect of the C-H⋯O with the O-H⋯OS.

Reply to “Comments on measurement and relationships of density and viscosity of 1,2 propylene glycol + dimethyl sulfoxide mixtures and spectral insight”

Reply to “Comments on measurement and relationships of density and viscosity of 1,2 propylene glycol + dimethyl sulfoxide mixtures and spectral insight”

Assessing cellulose dissolution efficiency in solvent systems based on a robust experimental quantification protocol and enthalpy data

Abstract Dissolution of microcrystalline cellulose (MCC) in pure ionic liquids (ILs) and IL/dimethyl sulfoxide (DMSO) mixtures (mole fraction χDMSO = 0.2–0.9) was quantified using a specially constructed mechanical stirring system that allows reproducible agitation speed; temperature control, and minimum solution-air contact. The electrolytes employed were: 1-(n-butyl)-3-methylimidazolium acetate (C4MeIm AcO), 1-(methoxyethyl)-3-methylimidazolium acetate (C3OMeIm AcO), 1,8-diazabicyclo[5.4.0]undec-7-enium acetate (DBU AcO), tetramethylguanidinium acetate (TMG AcO), and tetra(n-butyl)ammonium fluoride hydrate (TBAF·xH2O). The effects on MCC dissolution of IL/DMSO composition, and temperature (50, 70°C) were studied. C4MeIm AcO and C4MeIm AcO/DMSO were more efficient solvents than their C3OMeIm AcO counterparts, due to “deactivation” of the ether oxygen of C3OMeIm AcO. MCC dissolution by C4MeIm AcO/DMSO was compared with DBU AcO/DMSO, TMG AcO/DMSO at χDMSO = 0.6, and TBAF·xH2O/DMSO at χDMSO = 0.95. The relative efficiency was (solutions in DMSO): C4MeIm AcO &gt; C3OMeIm AcO &gt; DBU AcO &gt; TMG AcO &gt; TBAF·xH2O. The efficiency of C4MeIm AcO relative to C3OMeIm AcO is due to higher solution basicity. Isothermal titration calorimetry was used to study cellobiose-solvent interactions. Except for TBAF·xH2O/DMSO, these interactions are exothermic; the relative solvent efficiency increases with increasing dissolution |enthalpy|. Using the mole fraction concentration scale to report cellulose dissolution avoids possible ambiguities.

Comments on “The density, dynamic viscosity and kinematic viscosity of protic and aprotic polar solvents (pure and mixed) systems: An experimental and theoretical insight of thermophysical properties”

A search of the chemical and engineering literature revealed that the excess molar volumes given in the published paper by Alam and coworkers for both binary water + N,N-dimethylformamide mixtures and binary water + dimethyl sulfoxide mixtures differ significantly from values determined by several independent research groups.