Why mercury prefers soft ligands

Journal Article · Tue Jan 01 04:00:00 EST 2013 · Journal of Physical Chemistry Letters

DOI:https://doi.org/10.1021/jz401075b· OSTI ID:1098205

Riccardi, Demian M ^[1]; Guo, Hao-Bo ^[1]; Gu, Baohua ^[1]; Parks, Jerry M ^[1]; Summers, Anne ^[2]; Miller, S ^[3]; Liang, Liyuan ^[1]; Smith, Jeremy C ^[1]

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1. ORNL
2. University of Georgia, Athens, GA
3. University of California, San Francisco

Mercury (Hg) is a major global pollutant arising from both natural and anthropogenic sources. Defining the factors that determine the relative affinities of different ligands for the mercuric ion, Hg2+, is critical to understanding its speciation, transformation, and bioaccumulation in the environment. Here, we use quantum chemistry to dissect the relative binding free energies for a series of inorganic anion complexes of Hg2+. Comparison of Hg2+ ligand interactions in the gaseous and aqueous phases shows that differences in interactions with a few, local water molecules led to a clear periodic trend within the chalcogenide and halide groups and resulted in the well-known experimentally observed preference of Hg2+ for soft ligands such as thiols. Our approach establishes a basis for understanding Hg speciation in the biosphere.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1098205
• Journal Information: Journal of Physical Chemistry Letters, Journal Name: Journal of Physical Chemistry Letters Journal Issue: 14 Vol. 4; ISSN 1948-7185
• Country of Publication: United States
• Language: English