A Kamikaze Approach for Capturing Hg2+ Ions through the Formation of a One-Dimensional Metal-Organometallic Polymer

Efficient uptake of Hg2+ 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 Hg2+ ions. In the presence of Hg2+ 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 Hg2+ 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 (similar to 99%) of Hg2+ ions from aqueous solutions through an underexplored kamikaze approach involving a small-molecule ligand as a sacrificial agent for trapping the ion.