Mercury chloride, reaction with metal ligands

The above reactions in this section have been examples of addition alone or addition followed by elimination. Ligand reactions involving nucleophilic substitution are also known and these are of the dealkylation type. Lewis acids such as aluminum chloride or tin(IV) chloride have been used for many years in the selective demethylation of aromatic methyl ethers, where chelation is involved (Scheme 27). Similar cleavage of thioethers, specially using mercury(II) salts, is commonly used to remove thioacetal functions masking ketones (equation 27).104 In some cases, reactions of metal ions with thioether ligands result in isolation of complexes of the dealkylated organic moiety (equations 28 and 29).105-107... 

In the reaction of organic monocationic chlorides or coordinatively saturated metal-ligand complex chlorides with linear, neutral Hg(CN)2 building blocks, the Lewis-acidic Hg(CN)2 moieties accept the chloride ligands to form mercury cyanide/chloride double salt anions that in several cases form infinite 1-D and 2-D arrays. Hg chemical shift tensors and J( C, Hg) values measured in selected compounds reveal that the NMR properties are dominated by the Hg(CN)2 moiety. ... 

NickeI(II) (rf ).— The mechanism of complex formation for some metal(ii) cations is now so well established, at least for simple ligands, that such reactions, particularly of nickel(n), are used to probe solvent and salt effects on kinetic patterns. Many of these studies are therefore dealt with in the Chapter on medium effects (Part II, Chapter 13). They include the reactions of nickel(n) and of magnes-ium(n) with chloride in aqueous alcohols, of nickel(ii) with imidazole in aqueous ethanol, with malonate in fructose-water solutions, with thiocyanate in methanol-DMSO mixtures, and with murexide or pada in various micellar media, and of several metal(n) cations with fluoride in aqueous salt solutions." In general, medium effects on observed rate constants (lit) for complex formation operate on the pre-association step (/fos) rather than on the interchange process (A i). The Eigen-Wilkins mechanism operates in all these media it has also been shown to operate for the bidentate ligand Etgdtc in DMSO, and even at the surface of a mercury electrode. ... 

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