Properties Of Dimethyl Sulfoxide Research Articles

Structural Features of a Family of Coumarin-Enamine Fluorescent Chemodosimeters for Ion Pairs.

A family of coumarin-enamine chemodosimeters is evaluated for their potential use as fluorescent molecular probes for multiple analytes [cadmium(II), cobalt(II), copper(II), iron(II), nickel(II), lead(II), and zinc(II)], as their chloride and acetate salts. These fluorophores displayed excellent optical spectroscopic modulation when exposed to ion pairs with different Lewis acidic and basic properties in dimethyl sulfoxide (DMSO). The chemodosimeters were designed to undergo excited-state intramolecular proton transfer (ESIPT), which leads to significant Stokes shifts (ca. 225 nm) and lower-energy fluorescence emission (ca. 575 nm). A more basic anion, e.g., acetate, inhibited the ESIPT mechanism by deprotonation of the enol, producing a binding pocket (N^O- chelate) that can coordinate to an appropriate metal ion. Coordination of the metal ions enhances the fluorescent intensity via the chelation-enhanced fluorescence emission mechanism. Subjecting the spectroscopic data to linear discriminant analysis provided insights into the source of these systems' markedly different behavior toward ion pairs, despite the subtle structural differences in the organic framework. These compounds are examples of versatile, low-molecular-weight, dual-channel fluorescent sensors for ion-pair recognition. This study paves the way for using these probes as practical components of a sensing array for different metal ions and their respective anions.

Synthesis and Electrochemical Properties of Aluminum Hexafluorophosphate.

We report the first synthesis of aluminum hexafluorophosphate (Al(PF6)3) and its electrochemical properties in dimethyl sulfoxide (DMSO). The single crystal structure of the synthesized Al(PF6)3 is revealed as [Al(DMSO)6](PF6)3, and 0.25 M Al(PF6)3 in DMSO with high ionic conductivity is obtained. The purity of this electrolyte was further confirmed with nuclear magnetic resonance spectroscopy and electrospray ionization mass spectrometry. We then demonstrated the reversibility of Al deposition-stripping in this electrolyte using scanning electron microscopy and an X-ray photoelectron spectroscopy depth profiling study. The parasitic reaction involving DMSO decomposition during Al deposition is also identified via gas chromatography/electron ionization mass spectrometry.

Glucose conversion to 5-hydroxymethylfurfural with chromium exchanged bentonite and montmorillonite catalysts in different solvents

Synthesis of 5-hydroxymethylfurfural (HMF) was studied using Cr-montmorillonite and Cr-bentonite catalysts. Catalysts were characterized by Brunauer–Emmett–Teller surface area analyzer, X-ray diffraction (XRD), infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The effects of temperature and time on the conversion of glucose to HMF were investigated with different solvent-catalyst systems. HMF yield (45%) was obtained at 140 °C for 20 min using Cr-montmorillonite in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid. The 62.6% HMF yield was efficiently achieved at 150 °C for 10 min in [BMIM]Cl using Cr-bentonite. Cr-bentonite catalyst has good reusable properties in dimethyl sulfoxide (DMSO). The 94% of catalytic efficiency was maintained at the end of fifth use in DMSO.

A Simple Method to Synthesize Lignin Nanoparticles

The self-assembly of lignin (molecular and supramolecular) is driven mainly by non-covalent interactions, and the nature of the solvents and antisolvents directly affect the driving forces. The lignin particle is usually formed by noncovalently bonded cylindrical subunits. In this paper, we report a simple method which can be used to synthesize lignin nanoparticles by using spray freezing. The method is based on two properties of dimethyl sulfoxide (DMSO) that are excellent lignin solubility and a high melting point. Based on these two properties, kraft lignin solution in DMSO was sprayed onto liquid nitrogen-cooled copper plates using a handheld spray. The high melting point of DMSO caused immediate freezing and particle formation. The obtained particles were characterized for their size and morphology using dynamic light scattering (DLS), as well as scanning electron microscopy (SEM). Nano-range polydispersed particles were obtained by spraying 0.05% of lignin onto DMSO. This method can avoid lignin–solvent–antisolvent interactions, and can also be used to study lignin–lignin (subunits) and lignin–DMSO interactions.

NH-кислотность замещенных трихлорэтилацетамидов в среде диметилсульфоксида

In this work, we synthesized a series of N-(2,2,2-trichloroethyl) amides with the general formula of RCONHCH (R´) CCl 3 (where R = CH 3 , CH 2 Cl; R´ = C 6 H 5 , C 6 H 4 CH 3 , C 6 H 4 OCH 3 , C 6 H 4 OH) and investigated their acid/base properties in dimethyl sulfoxide (DMSO). For the first time, the curves and constants for the NH-acidity of the acetamides have been drawn using titration data. Under the potentiometric titration of the acetamides, curves with a pronounced jump in the potential of the indicator electrode were obtained in all the studied cases. The NH-acidity of the acetamides under study is shown to depend on the polar effects of substituents. The possibility of quantitative potentiometric analysis of individual acetamides, as well as double and ternary mixtures under their joint presence with sulfonamides in DMSO, was established. The metrological characteristics of the results obtained during a potentiometric determination of the constants under consideration were evaluated. These characteristics are demonstrated to possess a fairly high laboratory precision, with the coefficient of variation ranging from 0,04% to 0,52%. The obtained results were verified using the “introduced-found” method.

Abnormal characteristics of binary molecular clusters in DMSO–ethanol mixtures under external electric fields

ABSTRACTFor the nonlinearly phenomena on the dielectric properties of dimethyl sulfoxide (DMSO)–ethanol mixtures under a low intensity microwave field, we propose a conjecture that there exist some abnormal molecular clusters. To interpret the mechanism of abnormal phenomena and confirm our conjecture about the existence of abnormal molecular clusters, an in-depth investigation about the structure evolutions of (DMSO)m(C2H5OH)n (m = 0–4; n = 0–4; m + n ≤ 4) molecular clusters induced by external electric fields has been given by using density functional theory. The results show that there exist some binary molecular clusters with large cluster radii in mixtures, and some of them are unstable under exposure of electric fields. It implies that the existence of certain abnormal molecular clusters in DMSO-ethanol mixtures results in their abnormality of dielectric properties.

Investigation of synthetic pathways of carboxylic acid phthalocyanines from glycolic and lactic acids

We present the study of synthetic pathways to prepare carboxylic acid substituted phthalocyanines from glycolic and lactic acids. Hydroquinone was used as an alternative catalyst for cyclotetramerization reaction of metal free and zinc phthalocyanines, which were characterized by 1H MR spectroscopy, infrared absorption and mass analysis. The photophysical and photochemical properties in dimethyl sulfoxide (DMSO) were analyzed. We verified that the presence of the methyl radical group, that distinguish both structures, diminish the macrocycle aggregation in solution and promote higher quantum yields of fluorescence and for singlet oxygen generation.

A Hemimethyl-Substituted Cucurbit[7]uril Derived from 3α-Methyl-glycoluril.

A novel hemimethyl-substituted cucurbit[7]uril (HMeQ[7]) derived from 3α-methyl-glycoluril has been prepared. HMeQ[7] is readily soluble in both water and dimethyl sulfoxide (DMSO) and displays not only host-guest interaction properties similar to those of the normal cucurbit[7]uril but also unusual properties in DMSO.

Effect of dimethyl sulfoxide on inhibition of post-ovariectomy osteopenia in rats

There is increasing evidence that oxidative stress, due to estrogen deficiency, leads to osteopenia. In this study, dimethyl sulfoxide (DMSO), an antioxidant solvent, was used against post-ovariectomy osteopenia (PO) in rats. Forty female rats were divided into 5 groups randomly as follows: Sham, control group; OVX, ovariectomized group; DMSO1, ovariectomized injected DMSO (0.5 ml/kg/d ip); DMSO2, ovariectomized injected DMSO (1 ml/kg/day ip) and DMSO3, ovariectomized injected DMSO (2 ml/kg/d ip). DMSO therapy started 1 week after ovariectomy and continued for 13 weeks. After 13th weeks, sera were prepared, and then L4 vertebrae and right tibial bones rinsed in fixative. Serum bone alkaline phosphatase (BALP), osteocalcin, pyridinoline, malondialdehyde (MDA) and glutathione (GSH) were measured. Trabecular volume density, trabecular and cortex thickness were estimated. Osteoclast and osteoblast numbers were counted morphometrically. The data were analyzed by ANOVA and then post hoc Tukey test at p < 0.05. The increase of pyridinoline and decrease of BALP in DMSO injected groups were inhibited compared with OVX group (p < 0.05). In DMSO injected groups, decrease of bone density, trabecular volume density, thickness of trabecular and tibial cortex were inhibited compared with OVX group (p < 0.05). MDA decreased significantly in DMSO injected groups compared with OVX group. Osteoclast number decreased in DMSO injected groups compared with OVX group (p < 0.05). Osteoblast number did not show significant change in DMSO groups compared with OVX group. In conclusion, DMSO ameliorates PO through decrease of osteoclast number, osteoclast inhibition and osteoblast activation. These effects may probably be mediated via antioxidant property of DMSO.

Cardioprotective Properties of Dimethyl Sulfoxide during Global Ischemia–Reperfusion of Isolated Rat Heart

Cardioprotective properties of dimethyl sulfoxide (DMSO) were studied in the isolated rat heart model. Intraperitoneal administration of DMSO to animals for 3 days before the experiment, but not addition of DMSO to the perfusate, reduced infarction size. Both intraperitoneal and intracoronary administration of DMSO reduced the severity of postischemic left-ventricular dysfunction.

Electrodeposition of Tm-Co Alloy Films in Dimethylsulfoxide

The conductivity of three thulium (Tm) salts has been studied in dimethylsulfoxide (DMSO) at 298 K. has strong electrolyte properties in DMSO. Cyclic voltammetry has been used to investigate the electrochemical behavior of the ion in 0.01 mol L−1 -0.1 mol L−1 -DMSO system on the Pt electrode at 299 K. The experimental results of cyclic voltammetry indicate that the reduction of the ion is an irreversible process. The transfer coefficient and the diffusion coefficient of ion have been measured. In a nonaqueous system, the surface of Tm-Co alloy films prepared by the potentiostatic deposition technique is uniform, adhesive, compact, and showed a metallic luster. Tm-Co alloy films are amorphous, as proven by X-ray diffraction spectrometry. Tm-Co alloy films have soft magnetic property at 293 K. This kind of rare earth film prepared from organic solvent could have the potential application as a magnetic material. © 2004 The Electrochemical Society. All rights reserved.

The force field and molecular structure of dimethylsulfoxide from spectroscopic and gas electron diffraction data and ab initio calculations

Scale factors on the ab initio force field of dimethyl sulfoxide (DMSO) produced by the HF/6-31G∗∗ method have been fitted using vibrational frequencies of the isotopomers DMSO-h6 and DMSO-d6 as well as centrifugal distortion constants of a total of nine isotopomers. As indicated by the ab initio calculated sequences of the methyl deformation and methyl rocking vibrations, the attribution to the symmetry species A′ and A″ have been reversed compared to previous work. Then fitting 12 scale factors, the experimental vibrational frequencies are reproduced to 0.6%.Subsequently, the molecular structure of gaseous DMSO has been investigated by a combined analysis of electron diffraction data, rotational constants and ab initio calculations. The fitted quadratic force field was used to calculate the mean amplitudes of vibration, to obtain the necessary harmonic corrections for the conversion of B0 rotational constants to Bz, and to determine the isotopic differences in bond lengths. The rav structural parameters (uncertainties in parenthesis are 3σ) we obtained from the present analysis are: SO=1.4837(11)Å,C–S=1.8071(8)Å,C–H=1.0934(23)Å, ∠C–S–C=96.56(6)°, ∠(C–S–C)plane and SO bond=115.43(5)°. The geometry of DMSO has been optimized using the methods: HF/6-31G(p,d), DFT/B3LYP/6-311++G(3df,3pd), DFT/B3PW91/6-311++G(3df,3pd), MP2/6-31G(d,p), MP2/6-311++G(3df,3pd) and QCISD(T)/6-311++G(2d). The structural parameters predicted at these levels of theory have been discussed and compared with the experimental results. The values for the geometrical parameters provided by the DFT/B3PW91/6-311++G(3df,3pd) method are in best agreement with the experimental results. The importance of the inclusion of the d-polarization functions on sulfur has also been investigated. Our results support earlier observations emphasizing the needlessness of the hypervalency concept for describing the bonding properties in DMSO because the SO bond is ionic and thus the octet rule is not violated.

Solvent assistance in regiospecific disulfide formation in dimethylsulfoxide

This paper describes a convenient oxidative refolding method that exploits the dual property of dimethylsulfoxide (DMSO) as an oxidant and a solvent 'chaperon' in assisting disulfide formation in peptides. Synthetic peptides with preferred secondary structures were used as models. For β-sheet peptides, an active fragment of fibroblast growth factor containing the tetrapeptide Arg-Ser-Arg-Arg at a reverse turn was used. A disulfide scan consisting of 16 analogs is designed in which different pairs of amino acids on the antiparallel β-sheets flanking the active determinants are replaced with cysteine. DMSO in aqueous buffer at pH 6 or 8 was found to minimize aggregation due to β-sheet formation in all 16 β-stranded peptides and provided monocyclic disulfide peptides within 7 h. In contrast, air oxidation required a significantly longer duration for completion under similar conditions, and only 8 of 16 peptides formed intramolecular disulfides. Rate accelerations at pH 8 were found in exo-disulfide formation involving peptides with amino terminal cysteine, irrespective of oxidation conditions. The exo-disulfide effect in accelerating disulfide formation may be useful for regiospecific disulfide formation. For α-helix peptides, the two-disulfide endothelin (ET) was used as a model. DMSO in combination with trifluoroethanol (TFE) was found to favor the desired bicyclic 1,4-disulfide bridged ET (1,4-ET) over the incorrectly folded 1,3-ET. Under aqueous conditions at pH 5–11, 1,4-ET to 1,3-ET was formed in the ratio of approximately 3:1, while the use of DMSO and TFE increased the ratio to 11:1. This solvent combination may stabilize an α-helical stretch found in ET and contribute to enhanced selectivity. Thus, our results show that DMSO in disulfide formation in an aqueous or helix-promoting solution may serve as an oxidant and a 'chaperon' solvent system to provide regiospecificity for oxidative disulfide formation.

Redox-active polymers: synthesis and exchange reaction of amino compounds containing a cyclic disulfide

Two monoamidated amino compounds, bearing the cyclic disulfide moiety of lipoic acid, were prepared by imidazole group transfer with aliphatic diamines (1,3-diaminopropane and piperazine). The products, characterized by spectroscopic methods ( 1H nuclear magnetic resonance and Fourier-transform infra-red), were studied in solution. Basicity constants for the protonation of the basic nitrogens were evaluated in aqueous media, and redox properties in dimethylsulfoxide, by cyclic voltammetry. Insoluble polymers were obtained by polymer-analogue exchange reaction of the monoamidated compound with a benzotriazole residue present in preformed poly( N-acryloylbenzotriazole). A copolymer of the same monomer with N-vinylpyrrolidinone was soluble in solvents, giving a response in cyclic voltammetry. Its positive anode peak was slightly higher than that of the simple monoamidated compounds.

Differences between Asn-Xaa-Thr-containing peptides: a comparison of solution conformation and substrate behavior with oligosaccharyltransferase

A series of tripeptides that satisfy the -Asn-Xaa-Thr/Ser- primary sequence requirement [Marshall, R. D. (1972) Annu. Rev. Biochem. 41, 673-702] for N-glycosylation have been synthesized and examined as potential acceptors in an oligosaccharyltransferase assay. Of these, six (Ac-Asn-Ala-Thr-NH2, Ac-Asn-Leu-Thr-NH2, Ac-Asn-Asp-Thr-NH2, Ac-Asn-D-Ala-Thr-NH2, Ac-Asn-Pro-Thr-NH2, and Ac-Asn-AIB-Thr-NH2) were examined for solution conformational properties in dimethyl sulfoxide with use of amide proton temperature coefficients, 3JHN alpha analysis [Pardi, A., et al. (1984) J. Mol. Biol. 180, 741-751], and 2-D ROESY experiments [Bothner-By, A. A., et al. (1984) J. Am. Chem. Soc. 106, 811-813]. The analysis reveals that the peptides that serve as acceptors in the transferase assay demonstrate similar conformational properties in solution. These are highlighted by a secondary structural motif that involves the interaction between the asparagine side-chain carboxamide and the backbone amide of the threonine. The peptides that show very poor acceptor, or even nonacceptor, properties in the oligosaccharyltransferase assay demonstrate different conformational features in solution. These observations may explain the distinct biological activity observed for these peptides.

Hydration of Aza-aromatic Aldehydes. I. Isolation of the Solid Hydrates and the Thermodynamic Properties in Dimethyl Sulfoxide

Abstract The covalent hydration forming geminal diol is shown to be general in six-membered aza-aromatic aldehydes substituted by a formyl group at ortho or para-position to the nitrogen atom, and the equilibrium constants and thermodynamic quantities of the reaction are determined by NMR spectroscopic measurements. The results are compared with those of their hemiacetal formation. In several cases, solid monohydrates are isolated and identified.

About some biochemical properties of dimethylsulfoxide and three of its homologues: is the acidic function essential for nonsteroidal antiinflammatory activities?

Dimethylsulfoxide and three related sulfoxides exhibit some of the biochemical properties of classical non steroidal antiinflammatory acidic drugs. Thusn-propyl sulfoxide,n-butyl sulfoxide and tetramethylene sulfoxide stimulate O2 consumption by rat liver mitochondria. These 3 compounds induce mitochondrial swelling. Lymphocyte welling is only induced by high doses ofn-propyl sulfoxide andn-butyl sulfoxide and not by tetramethylene sulfoxide.

Temperature dependence of amide proton chemical shifts: The secondary structures of gramicidin S and valinomycin

In cases where hydrogen-deuterium exchange studies are inconclusive in defining hydrogen bonded amide protons, it is useful to have an alternative basis. Kopple et al. 1969 have associated a decrease in temperature sensitivity of chemical shift in amides protons of cyclic hexapeptides with hydrogen bonding. In the present communication we wish to demonstrate how readily temperature dependence of amide proton chemical shifts may be used to arrive at the secondary structures of gramicidin S (Stern et al. 1968) and valinomycin (Ivanov et al. 1969). The former antibiotic is conformationally quite rigid (Quadrifoglio and Urry 1967). Valinomycin, on the other hand, exhibits a dish-like structure with surfactant properties in dimethylsulfoxide (DMSO) whereas in methanol + KBr it exists as a “pore” structure with the proper dimensions and character for selective binding of potassium. The power of the approach is further emphasized by the fact that all three conformations, one for gramicidin S and two for valinomycin, were arrived at, independently and in a short time, without prior knowledge of the work of Stern et al. 1968 and of Ivanov et al. 1969. Thus the present work, in addition to demonstrating the temperature method for elucidating secondary structure of polypeptides, may be taken as a confirmation of the gramicidin S and valinomycin structures.

Anomalous effects of dimethyl sulfoxide on the response of the mouse lens and cornea to x-irradiation: "protection" of lens and "sensitization" of cornea.

Radiation effects on the eye are of considerable interest from both radiobiologic and radiotherapeutic points of view. They have been the subject of many experimental and clinical investigations. A number of workers (e.g., 1-3) have shown that relatively small doses of ionizing radiation to the lens can cause posterior lenticular opacities. Relatively large, repeated exposures result in late corneal lesions (4). In clinical situations irradiation of the eye is avoided, if possible, by appropriate direction of the beam and by use of shields. Elaborate technics for shielding the eye during irradiation of the periorbital region with high-energy electrons have been reported (5, 6). In many instances, however, all scattered radiation cannot be prevented from entering the eye. Much work has been done on chemical protection of the lens against effects of ionizing radiation. Cysteine administered intravenously is an effective protector against radiation cataract (7), but when given by subconjunctival injection exerts only a moderately protective influence (8). Other substances, e.g., glutathione, are also somewhat effective in reducing radiation damage to the lens when given by intravenous injection (8). To our knowledge, no substance administered topically to the eye has been reported to protect the lens from radiation damage. Local lenticular protection, as opposed to systemic protection, would have the inherent advantage of reducing radiation damage to the lens while not affording concomitant protection to nearby tissue (e.g., periorbital tumors). In addition, protection by topical administration would be far simpler than the complex shielding technics otherwise required. Three properties of dimethyl sulfoxide (DMSO) suggested its possible use in topical application for protection of the lens from the damaging effects of ionizing radiation. First, it passes easily through biological membranes and even through intact skin (9, 10). Second, DMSO has been shown to be a radioprotective substance at levels of the animal (ll), the cell (12), and the molecule (13). Third, it can act as a penetrant carrier for other organic molecules (14), perhaps for a protector such as 13mercaptoethylamine (MEA).

Some Properties of Dimethyl Sulfoxide in Man

Some Properties of Dimethyl Sulfoxide in Man