Chemical-Shift Standards for 199Hg NMR Spectroscopy, 25 Years Later.

While 199Hg NMR is a well-established tool for elucidating details of coordination chemistry in biochemical and inorganic complexes, historically the technique has been associated with the use of an extremely toxic chemical, dimethylmercury [Me2Hg or (CH3)2Hg], as a reference standard. In the 25 years since an accidental exposure to Me2Hg led to the tragic death of Dr. Karen Wetterhahn, the community has learned a great deal about the insidious neurotoxicity of this compound as well as more appropriate ways to avoid exposure. Here, we track the general shift toward the use of alternative mercury reference standards and away from Me2Hg.