Phenylmercurie compounds

Kimura and Miller [29] have described a procedure for the determination of organomercury (methylmercury, ethylmercury and phenylmercury compounds) and inorganic mercury in soil. In this method the sample is digested in a steam bath with sulphuric acid (0.9M) containing hydroxy ammonium sulphate, sodium chloride and, if high concentrations of organic matter are present, potassium dichromate solution. Then, 50% hydrogen... 

There are three important routes to the formation of the mercury-transition metal bond (a) displacement of halogen or pseudohalogen from mercury(II) salts with carbonyl metallate anions (b) reaction of a halo-phenylmercury compound with a transition metal hydride and (c) oxidative addition of a mercury halide to neutral zero valent metals.1 We report here the syntheses of three compounds containing three-centre, two-electron, mercury-ruthenium bonds utilizing trinuclear cluster anions and mercury(II) halides.2-4... 

Following exposure to metallic mercury, the elimination of mercury can occur via the urine, feces, and expired air. Following exposure to inorganic mercury (mercuric), mercury is eliminated in the urine and feces. Organic mercury compounds are excreted predominantly via the feces in humans. In animals, methylmercury is excreted in the feces, and phenylmercury compounds are initially excreted in the feces and then in the urine. Organic mercury compounds are excreted predominantly in the inorganic form. Both inorganic mercury and methylmercury are excreted in breast milk. 

During the first few days after intravenous dosing, phenylmercury compounds are also eliminated primarily in the feces as a result of biliary secretion and its concentration in the gastrointestinal tract (mucosa and lumen) (Berlin and Ullberg 1963). The initial urinary excretion of phenylmercury represents primarily the parent compound (Gage 1964). Several days after exposure, however, elimination is primarily in the urine, which contains predominantly inorganic mercury (Gotelli et al. 1985). 

Mechanisms for the toxic effects of inorganic and organic mercury are believed to be similar. It has been suggested that the relative toxicities of the different forms of mercury (e g., metallic, monovalent, and divalent cations and methyl- and phenylmercury compounds) are related, in part, to its differential accumulation in sensitive tissues. This theory is supported by the observation that mercury rapidly accumulates in the kidneys and specific areas of the central nervous system (Rothstein and Hayes 1960 Somjenetal. 1973). 

Phenylmercuric acetate is another form of organic mercury to which the general public may be exposed. Although phenylmercury compounds are considered organomercurials, they are absorbed less efficiently by the gastrointestinal tract than is methylmercury. Once inside the body, phenylmercury is rapidly metabolized to Hg, and its effects are, therefore, similar to those of mercuric salts. 

One developmental study of phenylmercury compounds was reported by Gale and Ferm (1971) in which hamsters were injected intravenously with phenylmercuric acetate at doses ranging from 5 to 10 mg/kg on Gd 8. With the exception of the lowest dose, all other doses induced increased resorption rates and edema, along with a few miscellaneous abnormalities including cleft palate and exencephaly. 

Ishiyama (1969) found that the biological efficiency of phenylmercury compounds depends on the following order of activity of the R radical phenyl > o- and p-io y > ethyl-, methoxyethyl-, dimethylphenyl > naphthyl. 

It has been established in experiments investigating this phenomenon that phenylmercury compounds are degraded after their absorption and that the protective effect is actually indirect. By the action of these compounds, the quantity of amino acids (glutamic acid, alanine, etc.) decreases in the sap of the rice leaves, which increases the resistance of rice against rice blast. 

On the other hand, methoxyalkyl- and phenylmercury compounds are less stable, decomposing into mercury(II) salts and leaving the organism rapidly. A considerably larger amount, about one-third of the total quantity of mercury is excreted in urine, which also indicates a different metabolism. Miller et al., (1960) found that metalmercury could not be detected in any of the organs of the experimental animals only a relatively short time after feeding with phenylmercury acetate. 

Reduction with sodium borohydride is sometimes carried out on samples without previous digestion. Margel and Hirsh (1984) reported a detection limit of 1-2 /completely reduced at pH 9.5 and a temperature above 25°C. Copper sulfate had to be added to urine in order to get a satisfactory recovery of MeHg. However, in case of MeHg. Toffaletti and Savory (1975) reported the formation of an unidentified mercury compound, which was aerated from the sample, but was not detected by AAS unless the vapour was heated to about 700 °C. 

Miller, V.L., Lillis, D. and Csonka, E. (1958) Microestimation of intact phenylmercury compounds in animal tissue. Anal. Chem., 30,1705-1706. 

Phenylmercury compounds produce a pattern of toxicity intermediate between alkyl and inorganic mercury. 

Berlin M (1963 b) Renal uptake, retention and excretion of mercury. II. A study in the rabbit during infusion of methyl- and phenylmercury compounds. Arch. Environ. Health 6 626... 

Neutral routes to carbenes and carbenoids have continued to be examined, and Seyferth has extended his studies to embrace the phenylmercury compounds (102). 

Even the first emulsion paints emerging in the 1950s were not very susceptible to bacterial growth because the polyvinyl acetate binders used contained sufficient amounts of the free monomer vinylacetate and the hydrolysis product acetaldehyde (II, 2.2.) to prevent growth. In the 1950s phenylmercury compounds (II, 19.2.-3.) were used in low concentrations of 0.05 to 0.15% as a microbicide for the wet and the dry state, respectively. Alternatively, formaldehyde was very efficient to keep paints protected against bacterial growth, but in practice... 

In the EEC list of preservatives which cosmetic products may contain the use of PMA is limited to eye makeup and eye make-up remover only max. concentration 0.007% (of Hg). Such products must be labeled Contains Phenylmercury Compounds . - Percentage of use in US cosmetic formulations, 0.17% PMA, if no other effective and safe (Hg-free) preservative is available. 

Baughman et al 7 studied the gas chromatographic behaviour of methylmercury compounds on a glass column (6ft x 0.25in) packed with 5% of DECS on Chromosorb W and operated at 160°C, and of phenylmercury compounds on a similar column packed with 3% of OV-1 on Chromosorb W and operated at 150 C. Flame ionization and Ni electron-capture detectors were used. Dimethyl- and diphenylmercury were stable under these conditions, but combined glc-ms confirmed that methyl- and phenylmercury salts decompose during gas chromatography. Reliable determination of methylmercury salts were achieved only on columns specially treated so as to make the decomposition reaction reproducible. Phenylmercury salts, which decompose extensively, could not be determined by gas chromatography. 

Metal-substituted benzenes have a long history of use in medicine. Before antibiotics were discovered, phenylarsenic derivatives were the only treatment for a number of diseases. Phenylmercury compounds continue to be used as fungicides and antimicrobial agents to the present day. On the basis of the general principles explained in this chapter and your knowledge of the characteristics of compounds of Hg " (see Section 12-7), propose a sensible synthesis of phenylmercury acetate (shown below). 

Nishi and Horimoto [692,693] determined trace amoimts of methyl-, ethyl- and phenylmercury compounds in river waters and industrial... 

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