Organolead compound

Willemsens, L. C., Organolead Chemistry. A Concise Review with Special Reference to the Literature Covering the Period January 1953 to July 1963, International Lead and Zinc Research Organization, Inc., New York 1964. 

Shapiro, H., Frey, F. W, The Organic Compounds of Lead, Interscience, New York 1968. 

Grandjean, P., Grandjean, E. C., Biological Effects of Organolead Compounds, CRC, Boca Raton, FL, 1984. 

The method most used for preparation of organolead compounds in the laboratory is treatment of lead(n) chloride with alkyl-, aryl-, or vinyl-Grignard or -lithium reagents, the main products being as shown in the following summary for magnesium 163,395 463 464 

The lead products shown are accompanied by their homologs Pb2R6. 

Lead salts of other inorganic and of organic acids may replace the lead chloride, as also may lead oxide or sulfide, and these may be brought into reaction with organo-lithium, -magnesium, -zinc, or -aluminum compounds methods for obtaining tetraethyllead have been studied in particular detail.465 

In these reactions half the lead is reduced to metallic lead and may thus be considered a loss. To avoid this, compounds of quadrivalent lead such as lead(iv) acetate, and potassium or ammonium hexachloroplumbate, may replace the lead(n) salts,466 and their use with Grignard reagents or organo- 

Formation of metal-carbon bonds (organometallic compounds) 

The main concern regarding tetraalkyl lead has been about human health hazards, a concern that has resulted in the progressive replacement of leaded petrol by unleaded petrol in most countries (Environmental Health Criteria 85). There has been particular concern about possible brain damage to children in polluted urban areas. Little work has been done on the effects of organolead compounds on wildlife or ecosystems, so the following account will be brief. 

Lead tetramethyl and lead tetraethyl are covalent lipophilic liquids of low water solubility. Certain inorganic forms of lead, for example, lead tetrachloride, have similar properties, but other forms such as lead nitrate and lead dichloride are ionic and water soluble. Covalent and lipophilic forms of lead, like lipophilic forms of organomercury and organotin, can readily cross membranous barriers such as the 

Organic Pollutants An Ecotoxicological Perspective, Second Edition 

Lead tetraethyl is oxidized by the P450-based monooxygenase system to form the lead triethyl cation 

The application of a combination of gas chromatography and atomic absorption spectrometry to the determination of tetraalkyllead compoimds has also been studied by Segar [686]. In these methods the gas chromatography flame combination showed a detection limit of 

Chau et al. [687] developed a gas chromatographic method for the determination of ionic organolead species and applied it to samples of Lake Ontario water. When IL of sample water is taken the following species can be determined in amounts down to O.lpg L MejPb McjPb, EtjPbP EtjPb and Pb . 

Chau et al. [688,689] have described a simple eind rapid extraction procedure to extract the five tetraalkyllead compoimds (Me,Pb, McjEtjPb, MeEtjPb, MejEtjPb and Et,Pb) from non saline waters. The extracted compounds are analysed in their authentic forms by a gas chromato-graphic-atomic absorption spectrometry system. Other forms of inorganic lead do not interfere. The detection limit for water (200mL) is 0.50pg L 

Other applications of gas chromatography to the determination of organolead compounds in non saline waters are discussed in Table 15.17. 

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Chiral organolead compounds 19 can be obtained, with retention of configuration, from the corresponding a-alkoxy stannanes via tin/lilhium exchange and transmetalation with bro-mo(tributyl)lcad12. 

Seinen W, Vos JG, van Spanje I, Snoek M, Brands R, Hooykaas H (1977a) Toxicity of organotin compounds. II. Comparative in vivo and in vitro studies with various organotin and organolead compounds in different animal species with special emphasis on lymphocyte cytotoxicity. Toxicology and Applied Pharmacology, 42(1) 197-212. 

Certain OP compounds including DFP, mipafox, and leptophos Organomercury and organolead compounds... 

This chromatographic method might be used to try the separation of the enantiomers of a racemic mixture of asymmetrically substituted organolead compounds, which are now available 37>54). 

Ahlberg J, Ramel C, Wachtmeister CA. 1972. Organolead compounds shown to be genetically active. Ambio 1 29-31. 

Berg S, Jonsson A. 1984. Analysis of airborne organic lead. In Grandjean P, ed. Biological effects of organolead compounds. Boca Raton, FL CRC Press, 33-42. 

Grandjean P, Nielsen T. 1979. Organolead compounds Environmental health aspects. Res Rev 72 98-148. 

McClain RM, Becker BA. 1972. Effects of organolead compounds on rat embryonic and fetal development. Toxicol Appl Pharmacol 21 265-274. 

Organomercury and organolead compounds are much less reactive => they are often volatile and are stable in air. 

If we look at the intercomparison studies that have been made on the measurement of lead in seawater [21], two points become obvious first, that almost no one can measure lead accurately in seawater and second, that there is much less lead present than anyone had estimated. With so little lead present in any form, identification of the organic moiety of an organolead compound becomes a major problem. 

At least one of the organolead compounds has been shown to be a normal constituent of the aqueous environment. Tetramethyl lead has been found as a product of anaerobic bacterial metabolism in lake sediments [23]. It should perhaps be sought in the air over coastal mud flats. 

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