A Kamikaze Approach for Capturing Hg(2+) Ions through the Formation of a One-Dimensional Metal-Organometallic Polymer.

Efficient uptake of Hg(2+) ions in mercury-resistant bacteria is attributed to the presence of cysteine thiolates in the Mer proteins. In this work, a pyridine-appended pyridine-fused imidazolyl-2-thione scaffold was used as a mimic for the cysteinyl residues for efficient binding of the Hg(2+) ions. In the presence of Hg(2+) ions, an aryl C-H bond of the ligand is activated. The sulfur and nitrogen donors on the other end of the ligand coordinate with a second Hg(2+) ion. This motif in the presence of acetate ions forms a one-dimensional polymeric crystalline network characterized by singal-crystal X-ray diffraction studies. The formation of this polymeric structure leads to efficient removal (∼99%) of Hg(2+) ions from aqueous solutions through an underexplored "kamikaze" approach involving a small-molecule ligand as a sacrificial agent for trapping the ion.