Deuterated DMSO, also known as dimethyl sulfoxide-d₆, is an

isotopologue In chemistry, isotopologues are molecules that differ only in their isotopic composition. They have the same chemical formula and bonding arrangement of atoms, but at least one atom has a different number of neutrons than the parent. An exampl ...

of dimethyl sulfoxide (DMSO, (CH₃)₂S=O)) with chemical formula ((CD₃)₂S=O) in which the

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

atoms ("H") are replaced with their

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...

deuterium Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other being protium, or hydrogen-1). The nucleus of a deuterium atom, called a deuteron, contains one proton and one ...

("D"). Deuterated DMSO is a common

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

used in

NMR spectroscopy Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique to observe local magnetic fields around atomic nuclei. The sample is placed in a magnetic fie ...

Production

Deuterated DMSO is produced by heating DMSO in heavy water (D₂O) with a basic catalyst such as

calcium oxide Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline, crystalline solid at room temperature. The broadly used term "''lime''" connotes calcium-containing inorganic ...

. The reaction does not give complete conversion to the d₆ product, and the

water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

produced must be removed and replaced with D₂O several times to drive the equilibrium to the fully deuterated product.

Use in NMR spectroscopy

Pure deuterated DMSO shows no peaks in ¹H

and as a result is commonly used as an NMR solvent. However commercially available samples are not 100% pure and a residual DMSO-d₅ ¹H NMR signal is observed at 2.50ppm (quintet, J_HD=1.9Hz). The ¹³C chemical shift of DMSO-d₆ is 39.52ppm (septet).

References

{{List of NMR solvents Deuterated solvents