Other Alkylmercurials

Kombarova, L.A. Tvurina and V.V. Smirnov, Vestu. Mosk. Univ. Ser. 2 Khim, 

Castineiras, A. Macias, M.C. Rodriquez-Arguelles, A. Sanchez and J. Sordo, Inorg. Chm. Acta, 1992,197, 163. 

This review of the 1992 literature has a format which differs only slightly from that of last year. While the report is not comprehensive, an attempt has been made to achieve a reasonable coverage of the literature and to give a balanced survey of significant chemistry of organoboron compounds. The main source of refermices has beoi Chemical Abstracts, volumes 116 and 117 together with independ it surveys of the principal chemical journals. 

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Many organometallic compounds are best prepared by this reaction, which involves replacement of a metal in an organometallic compound by another metal. RM can be successfully prepared only when M is above M in the electromotive series, unless some other way is found to shift the equilibrium. That is, RM is usually an unreactive compound and M is a metal more active than M. Most often, RM is R2Hg, since mercury alkyls372 are easy to prepare and mercury is far down in the electromotive series.397 Alkyls of Li, Na, K, Be, Mg, Al, Ga, Zn, Cd, Te, Sn, etc. have been prepared this way. An important advantage of this method over 2-38 is that it ensures that the organometallic compound will be prepared free of any possible halide. This method can be used for the isolation of solid sodium and potassium alkyls.39R If the metals lie too close together in the series, it may not be possible to shift the equilibrium, For example, alkylbismuth compounds cannot be prepared in this way from alkylmercury compounds. 

The literature on epidemiologic findings is surveyed in other chapters of this book and elsewhere ( 5-7). As a summary, studies on food poisoning episodes have shown that the ingestion of alkylmercury and food oil contaminated by technical polychlorinated biphenyls leads to congenital defects in the offspring. It also appears to be relatively well proven that... 

Perfluoroalkyl derivatives of mercury were the first fluorocarbon-organometallic compounds to be reported. Alkylmercurials are valuable in that they are able to alkylate other metals, but the toxicity of mercurials greatly inhibits the use of these systems. Perfluoroalkyl iodides react with mercury on heating or irradiation with ultraviolet light to give perfluoroalkylmercury(ll) iodides [58-60] (Figure 10.17). 

Acute intoxication due to short-chain alkylmercury derivatives such as methyl- or ethylmercury produces signs and symptoms that differ significantly from intoxications with other mercury compounds. Usually, several weeks are required before the symptoms of poisoning become manifest. Even high lethal doses of methylmercury normally do not cause death before 4-7 weeks (Harada 1995). Clarkson (2002) stated that ethylmercury (a component of thiomersal in stabilizers of vaccines) is less stable, and consequently less toxic than methylmercury. Acute intoxication with short-chain alkylmercury compounds causes symptoms which are no different from those seen with chronic intoxication (see Section 17.6.5) (WHO 1990). 

Interestingly, a relationship analogous to the Perlin effect can also be found for other coupling constants, namely C- Hg in alkylmercurials (351) and in glycosylphosphonates (352) and cyclohexylphosphonates... 

Other organomercuriais. Alkylmercury compounds other than MeHg are not found in natural biological samples. Compounds like phenylmercury and alkoxyalkylmercury rapidly decompose in the body into Hg(ll), which binds to different ligands (cf. Skerfving, 1972a). 

For most purposes of structural studies it is desirable to obtain a purified compound free from other reaction products or other impurities accumulated during the preparation. Solids which are sufficiently soluble in hydrocarbon solvents to permit recrystallization are therefore most desirable. The first isolation of organolithium compounds was effected by Schlenk and Holtz in 1917 (5). Their method of preparation involved a metal-metal interchange with alkylmercury compounds, e.g.. 

Unlike alkylmercurials, which transfer their alkyl groups to other metals... 

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