Perdeuteriodimethyl sulfoxide
[CAS 2206-27-1]

Identification

• Classification: Chemical reagent >> Deuterated reagent
• Name: Perdeuteriodimethyl sulfoxide
• Synonyms: Hexadeuteriodimethyl sulfoxide
• Molecular Formula: C₂D₆OS
• Molecular Weight: 84.17
• CAS Registry Number: 2206-27-1
• EC Number: 218-617-0
• SMILES: [2H]C([2H])([2H])S(=O)C([2H])([2H])[2H]

Properties

• Density: 1.1±0.1 g/cm³ Calc.^*, 1.19 g/mL (Expl.)
• Melting point: 20.2 °C (Expl.)
• Boiling point: 189.0±9.0 °C 760 mmHg (Calc.)^*, 189 °C (Expl.)
• Flash point: 85.0 °C (Calc.)^*, 87 °C (Expl.)
• Index of refraction: 1.48 (Calc.)^*, 1.476 (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319
• Safety Statements: P264-P264+P265-P280-P302+P352-P305+P351+P338-P321-P332+P317-P337+P317-P362+P364

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Flammable liquids	Flam. Liq.	4	H227

Discovery and Applications

Perdeuteriodimethyl sulfoxide (commonly written as DMSO-d6) is a fully deuterated isotopologue of dimethyl sulfoxide, in which all hydrogen atoms of the two methyl groups are replaced by deuterium atoms. It is a polar aprotic solvent widely used in analytical chemistry, particularly in nuclear magnetic resonance (NMR) spectroscopy.

Dimethyl sulfoxide (DMSO) itself is a well-known organosulfur compound containing a sulfoxide functional group, characterized by a sulfur atom doubly bonded to oxygen and bonded to two methyl groups. The compound gained prominence in the mid-twentieth century due to its unusual combination of high polarity, ability to dissolve both polar and nonpolar compounds to some extent, and relatively low toxicity compared with many other polar aprotic solvents. These properties made it a versatile solvent in organic synthesis, chemical analysis, and biological studies.

Perdeuteriodimethyl sulfoxide was developed to serve primarily as an NMR solvent. In proton NMR spectroscopy, residual solvent signals can interfere with the detection and interpretation of sample spectra. By replacing the hydrogen atoms in the methyl groups with deuterium, the number of ¹H nuclei in the solvent is greatly reduced, significantly decreasing background signals. This enables clearer observation of analyte proton resonances and improves spectral resolution and quantification accuracy.

The structure of DMSO-d6 is identical to that of regular DMSO except for isotopic substitution. The sulfur–oxygen bond and sulfur–carbon bonds remain unchanged in their connectivity, and deuterium substitution does not significantly alter the electronic structure of the molecule. However, deuterium has different nuclear spin properties and mass compared with hydrogen, which makes it detectable by deuterium NMR and invisible in conventional proton NMR under standard conditions.

DMSO is classified as a polar aprotic solvent due to its high dielectric constant and lack of hydrogen bond donation capability. It can strongly solvate cations through coordination to the oxygen atom while stabilizing anions through its polarizable structure. This combination makes it particularly effective in facilitating reactions involving charged or polar intermediates, such as nucleophilic substitution reactions and certain types of elimination reactions.

In its perdeuterated form, DMSO retains these solvent properties while minimizing interference in spectroscopic measurements. It is therefore one of the most commonly used solvents for high-resolution NMR spectroscopy, especially for compounds that are insoluble in less polar deuterated solvents such as deuterated chloroform or benzene.

From a physical chemistry perspective, DMSO-d6 remains a high-boiling, hygroscopic liquid with strong solvent–solute interactions. Its ability to accept hydrogen bonds allows it to interact strongly with solutes containing hydroxyl, amino, and other polar functional groups. The isotopic substitution does not meaningfully alter its macroscopic solvent behavior, although subtle differences in vibrational frequencies and diffusion properties can be observed.

In addition to its role in NMR spectroscopy, DMSO and its deuterated analogue are also used in biochemical and pharmaceutical research. DMSO is known for its ability to penetrate biological membranes and is sometimes used as a cryoprotectant for cells and tissues. However, DMSO-d6 is primarily restricted to analytical applications rather than biological use due to cost and isotopic enrichment.

The preparation of perdeuterated DMSO typically involves isotopic exchange and synthetic routes that incorporate deuterium at the methyl positions, followed by oxidation of dimethyl sulfide derivatives. The resulting product is highly enriched in deuterium to ensure minimal residual proton signal in NMR applications.

Overall, perdeuteriodimethyl sulfoxide is a deuterium-labeled form of dimethyl sulfoxide designed primarily as an NMR solvent. Its importance lies in its combination of excellent solvent properties and isotopic purity, which enables high-resolution spectroscopic analysis of organic and inorganic compounds without significant interference from solvent proton signals.

References

2026. Erratum to: [3+3]-Cyclocondensation of β-Carbonyl-Substituted 4H-Chromenes with 3- and 6-Aminoindazoles: Synthesis of Pyrimido[1,2-b]indazoles and Pyrazolo[3,4-f]quinolines. Russian Journal of General Chemistry.
DOI: 10.1134/s1070363225606271

2026. Low molecular weight 4,4’-quinocyanines for in vivo NIR-II fluorescence imaging. npj Imaging.
URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12960835

2026. Synthesis and Characterization of Terpyridine Derivatives as Fluorescence Probe for Selective Detection of Ga3+ Ions in Acidic Conditions. Journal of Fluorescence.
DOI: 10.1007/s10895-026-04731-6