Deuterated DMSO explained

Deuterated DMSO, also known as dimethyl sulfoxide-d₆, is an isotopologue of dimethyl sulfoxide (DMSO, (CH₃)₂S=O)) with chemical formula ((CD₃)₂S=O) in which the hydrogen atoms ("H") are replaced with their isotope deuterium ("D"). Deuterated DMSO is a common solvent used in NMR spectroscopy.

Production

Deuterated DMSO is produced by heating DMSO in heavy water (D₂O) with a basic catalyst such as calcium oxide. The reaction does not give complete conversion to the d₆ product, and the water produced must be removed and replaced with D₂O several times to drive the equilibrium to the fully deuterated product.^[1]

Use in NMR spectroscopy

Pure deuterated DMSO shows no peaks in ¹H NMR spectroscopy and as a result is commonly used as an NMR solvent.^[2] 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).^[3]

Notes and References

1. DE. 1171422B. application. Process for the production of hexadeuterodimethyl sulfoxide. 1964-06-04. 1962-10-25. 1962-10-25. Fruhstorfer, Wolfgang. Hampel, Bruno. E. Merck A.G..
2. Chandak . MS . Nakamura . T . Takenaka . T . Chaudhuri . TK . Yagi-Utsumi . M . Chen . J . Kuwajima . K . 22 January 2013 . The use of spin desalting columns in DMSO-quenched H/D-exchange NMR experiments . . en . Hoboken, New Jersey, USA . . 22 . 4 . 486–91 . 10.1002/pro.2221 . 3610054 . 23339068 . subscription . 2 June 2023.
3. Gottlieb . Hugo E. . Kotlyar . Vadim . Nudelman . Abraham . 17 October 1997 . NMR Chemical Shifts of Common Laboratory Solvents as Trace Impurities . . en . Washington, D.C., USA . . 62 . 21 . 7512–7515 . 10.1021/jo971176v . 11671879 . subscription . 18 June 2011.