Mercury complexes oxygen ligands

Complexes of Mercury(l) with Oxygen-Donor Ligands. 

Zinc and cadmium complexes of the novel tripod ligand (145) have also been described.1087 The reaction of Hg(HL)2 (HL = 2-mercaptobenzoic acid, 146) with cadmium nitrate leads to the novel CdHgL species, in which the cadmium is bonded to the carboxylate oxygen atom, and the mercury to the thiolate sulfur.1088... 

Polyaza-, polythia-ligands. Recognition of transition metal ions. Replacing the oxygen sites with nitrogen or sulphur yields macrocycles and cryptands that show marked preference for transition metal ions and may also allow highly selective complexation of toxic heavy metals such as cadmium, lead and mercury [2.41-2.44, A.14]. 

Tetrahedral and octahedral complexes of zinc, cadmium, and mercury with a wide variety of nitrogen and oxygen donor ligands have been reported. Metal complexes... 

Mercury is the only group 12 member to have a substantial chemistry in the -1-1 oxidation state, in which Hg2 +, the most common of all metal polycations, is formed. This ion was the first one known to exhibit metal-metal bonding. Its chloride salt is the material present in the standard calomel reference electrode. In addition to halides and oxy salts, nitrogen and oxygen-donor ligand complexes of mercury(I) are known, but far fewer than of mercury(II). 

The divalent state of mercury (Hg ) dominates in most natural water however, elemental Hg° is the most stable form in a broad pE/pH range. Hg forms very strong complexes with oxygen and sulfur ligands, as well as with chloride. A significant hydrolysis starts at pH> 1 and dominates at pH >2, in the absence of other complexing agents. The chloride... 

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