Ultrasonic measurements and liquid structure of DMSO–water mixture

Madigosky, W. M.; Warfield, R. W.

doi:10.1063/1.444935

Cited by 51 publications

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“…Viscosity studies show a maximum in the shear viscosity concentration curve at 30% DMSO, while ultrasonic studies show a maximum of sound velocity absorption at about 30% DMSO at temperatures 0 ~ to 40~ [2]. These observations, together with the negative heat of mixing, have suggested that a strong hydrogen-bonded complex consisting of two water and one DMSO molecule exists [2].Anhydrous solution of p-toluenesulfonic acid in DMSO has shown continuous absorbance for the excess proton (energy bands) caused by symmetrical H-bonds with double minimum potential well in which the proton i040-0400/96/0400-0i 11509.50/0 9 1996 Plenum Publishing Corporation …”

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confidence: 97%

“…While the pure liquid DMSO is thought to have a cluster-like structure, upon addition of water, the cluster structure is suggested to gradually break up as the DMSO-water, water-water, and DMSO-DMSO interactions play a significant role [1]. Viscosity studies show a maximum in the shear viscosity concentration curve at 30% DMSO, while ultrasonic studies show a maximum of sound velocity absorption at about 30% DMSO at temperatures 0 ~ to 40~ [2]. These observations, together with the negative heat of mixing, have suggested that a strong hydrogen-bonded complex consisting of two water and one DMSO molecule exists [2].…”

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confidence: 99%

“…DMSO has found increasing use because of its ability to prevent freezing damage to living tissue and cells during low-temperature preservation. This "cryoprotective" action of DMSO appears to stem from its ability to retard water crystal formation within the ceils [2].The shape of DMSO is pyramidal, the corners being occupied by the two C atoms, the O atom, and the S atom. The S atom is sp 3 hybridized with a strongly polar S--O bond.…”

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confidence: 99%

“…Its large dipole moment (3.9D) and polarizability (nd = 1.478) enable it to stabilize molecules and ions through dipolar and induced dipolar interactions [1]. DMSO, apart from being widely used as a solvent, is a plasticizer, and a chemical intermediate [2]. It also shows many properties of biological interest, such as being a stimulating agent in drug adsorption and in enzymatic catalysis [1].…”

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Associated species of dimethylsulfoxide: Semiempirical modeling

Varnali

1996

Struct Chem

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Quantum chemical calculations have been carded to gain insight into the self-association of dimethylsulfoxide (DMSO), the interaction of DMSO with a solvent, and the protonation of DMSO. Different species that may be present in DMSO solutions have been modeled semiempirically.KEY WORDS: Dimethylsulfoxide; protonated dimethylsulfoxide; self-association; water-dimethylsulfoxide; modeling. ~TRODUCTION Dimethylsulfoxide (DMSO) is a polar aprotic solvent with a high dielectric constant (46.4) and hydroscopic nature [1]. Its large dipole moment (3.9D) and polarizability (nd = 1.478) enable it to stabilize molecules and ions through dipolar and induced dipolar interactions [1]. DMSO, apart from being widely used as a solvent, is a plasticizer, and a chemical intermediate [2]. It also shows many properties of biological interest, such as being a stimulating agent in drug adsorption and in enzymatic catalysis [1]. It causes increase in rates of bimolecular reactions over those in protic solvents [3]. DMSO has found increasing use because of its ability to prevent freezing damage to living tissue and cells during low-temperature preservation. This "cryoprotective" action of DMSO appears to stem from its ability to retard water crystal formation within the ceils [2].The shape of DMSO is pyramidal, the corners being occupied by the two C atoms, the O atom, and the S atom. The S atom is sp 3 hybridized with a strongly polar S--O bond. The geometry and GAPT (generalized atomic polar tensor) charges studied at the level of HF/6-311G** have been reported and one polarized bond and one almost fully ionic bond for the S--O pair has been demonstrated [4].Liquid DMSO is expected to be highly associated t Correspondence should be directed to Tereza Varnali, Bo~aziqi University, F.E.F. Kimya, Bebek, Istanbul, Turkey. 111as shown by its high boiling point and entropy of evaporation (which is higher than water) [3]. DMSO is thought to exist mainly as dimers in liquid state [5]. Self-associated complexes of DMSO in dilute solutions of CC14 [6] have been detected. At very low concentrations of DMSO in HCC13 there appears to be complete conversion of unassociated and self-associated species to the 1 : 1 and 1 : 2 chloroform complexes [5]. In Raman spectral studies of DMSO, the concentration of free DMSO is found to be of the order of 10% and increases to 60 % in dilute solutions in CC14 [3]. In aqueous solutions of DMSO the tendency toward formation of linear polymers of DMSO and DMSO-H20 complexes [3] is even more pronounced. A large negative enthalpy is associated with mixing DMSO and water [7]. While the pure liquid DMSO is thought to have a cluster-like structure, upon addition of water, the cluster structure is suggested to gradually break up as the DMSO-water, water-water, and DMSO-DMSO interactions play a significant role [1]. Viscosity studies show a maximum in the shear viscosity concentration curve at 30% DMSO, while ultrasonic studies show a maximum of sound velocity absorption at about 30% DMSO at temperatures 0 ~ to 40~ [2]. T...

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confidence: 99%

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Associated species of dimethylsulfoxide: Semiempirical modeling

Varnali

1996

Struct Chem

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“…It accounts for the fact that in sonic (compressional) waves volume elements are not just subject to shear but also to volume changes. If no relaxations occur at frequencies above the measurement range, η v = 2/3η s is predicted [7].…”

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High-Frequency Shear Viscosity of Low-Viscosity Liquids

Kaatze

Behrends

2014

Int J Thermophys

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A thickness shear quartz resonator technique is described to measure the shear viscosity of low-viscosity liquids in the frequency range from 6 MHz to 130 MHz. Examples of shear-viscosity spectra in that frequency range are presented to show that various molecular processes are accompanied by shear-viscosity relaxation. Among these processes are conformational variations of alkyl chains, with relaxation times τ η of about 0.3 ns for n-pentadecane and n-hexadecane at 25 • C. These variations can be well represented in terms of a torsional oscillator model. Also featured briefly are shear-viscosity relaxations associated with fluctuations of hydrogen-bonded clusters in alcohols, for which τ η values between 0.3 ns (n-hexanol) and 1.5 ns (n-dodecanol) have been found at 25 • C. In addition, the special suitability of high-frequency shearviscosity spectroscopy to the study of critically demixing mixtures is demonstrated by some illustrative examples. Due to slowing, critical fluctuations do not contribute to the shear viscosity at sufficiently high frequencies of measurements so that the non-critical background viscosity η bg of critical systems can be directly determined from highfrequency shear-viscosity spectroscopy. Relaxations in η bg appear also in the shearviscosity spectra with, for example, τ η ≈ 2 ns for the critical triethylamine-water binary mixture at temperatures between 10 • C and 18 • C. Such relaxations noticeably influence the relaxation rate of order parameter fluctuations. They may be also the U. Kaatze (B) 2089 reason for the need of a special mesoscopic viscosity when mutual diffusion coefficients of critical polymer solutions are discussed in terms of mode-coupling theory.

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Increased NOEs for small molecules using mixed solvents

Fesik

Olejniczak

1987

Magnetic Reson in Chemistry

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A simple procedure is proposed for increasing the size of NOEs in NMR studies of small molecules. The method involves the use of a mixed solvent (Me2SO-d6-D20) to increase the viscosity of the solution such that WT,> 1. The advantages of this solvent system and approach are compared with other approaches currently in use. KEY WORDS 'H NMR NOE Mixed solvent Small molecules INTRO D U CTI 0 NOne of the most useful tools for structure elucidation and conformational analysis by proton NMR is the nuclear Ovenhauser effect (NOE) e~periment.'-~ However, for small molecules NOEs between protons in close proximity are often very small or not observed at all.4x5 This occurs because the NOE observed between a pair of protons depends not only on the interproton distance but also on the frequency of motions of the interproton vector.' When the correlation time for the motion (7,) is close to the reciprocal of the spectrometer frequency ( w ) , i.e. w r c = 1, as is often the case for small molecules studied using high-field NMR spectrometers, then the NOEs are very small (positive or negative) or not observed.One of the methods proposed for enhancing the NOE in systems where WT,= 1 is the CAMELSPIN experiment.,-, Owing to the dependence of the rotating frame NOE on motional frequencies, positive NOEs are observed for all values of w and 7,. Although the CAMELSPIN experiment is very useful, it has some disadvantages when compared with the classical NOE experiment. These include the smaller maximum theoretical NOEs that may be achieved,, complications due to Hartmann-Hahn transfers between scalar coupled protons7" and the practical difficulties in setting up this experiment.An alternative approach in NOE studies of small molecules is to adjust the experimental conditions so that w r c is no longer close to unity. Varying the field strength ( w ) is not practical, since the highest field is preferred for greater sensitivity and resolution. A more attractive approach is to alter the frequency of motion, T,, by changing the solvent viscosity. Indeed, several solvents (e.g. tetramethylene-d, sulfone,' ethylene glycol-d, , l o phosphoric acid-d,," acetic acid-d,', and oil voltale 10S13) have been used for this purpose in NOE studies of small molecules.In this paper we describe the use of a mixed solvent system (Me,SO-d-D,O) for observing large NOEs as * Author to whom correspondence should be addressed.an aid in the structural elucidation and conformational analysis of small molecules. The relative advantages of this solvent system compared with those that have been previously proposed are discussed. EXPERIMENTALNMR data were acquired on a General Electric GN-300 NMR spectrometer operating at a frequency of 300.1 MHz and processed on a Vax 11/780 computer using an F T NMR program written by Dr Dennis Hare.Pure absorption two-dimensional NOE experiments were performed using a (90'-tl-90"-~,-90"-acquire),, pulse sequence. The real and imaginary parts of the t , dimension were separated by a phase cycling scheme described by States et ...

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Ultrasonic measurements and liquid structure of DMSO–water mixture

Cited by 51 publications

References 18 publications

Associated species of dimethylsulfoxide: Semiempirical modeling

Associated species of dimethylsulfoxide: Semiempirical modeling

High-Frequency Shear Viscosity of Low-Viscosity Liquids

Increased NOEs for small molecules using mixed solvents

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