Trimethyllead acetate

A blank and also a sterile solution containing Pb2+ of methyllead compounds showed no Pb content in the methanolic solution after the same treatment. The author concluded that Me4Pb was produced in the biomethylation of Pb2+ by bacteria123. Thompson and Crerar122 also observed that about 0.03% of lead as Pb(NC>3)2 underwent methylation and trimethyllead acetate, (CH3)3PbOAc, was methylated nearly quantitatively in incubation experiments with marine sediments from the British Columbia coastline. 

Some claims have, however, been made that the methylation of lead was not biologically mediated. In 1980, Craig126 studied the methylation of trimethyllead acetate in a lake sediment (Lake Minetonka, Minn., U.S.A.), and concluded that it is not necessary to invoke a biological route to the methylation and that the results in this case can be explained entirely by a disproportionation process126. Craig and Wood also proposed an abiotic methylation route of lead127. 

Trimethyltin acetate and trimethyltin trifluoroacetate108 propagate by glides to give rise to zigzag chains. The intramolecular and intermolecular O — Pb distances in trimethyllead acetate amount to 2.327 and 2.555 A109. 

Chau et al pointed out that as the authenticity of the compounds to be analyzed must be preserved, any of the digestion methods with acids or alkalis are not suitable, and that extraction seemed to be the method of choice for removing these compounds from samples. For this traction, they adopted benzene as recommended by Sirota and Uthe for the quantitative extraction of tetramethyllead and tetraethyllead from fish homogenates suspended in aqueous EDTA solution. Although ionic forms of lead such as Pb(II), diethyllead dichloride, and trimethyllead acetate do not extract in the benzene phase, any lead compounds that distribute into the benzene phase as tetraalkyllead will be determined. Chau et al421 found that environmental samples can contain other forms of organolead compounds that are extractable into benzene but which are not volatile enough to be analyzed by the GC-AAS technique, hence the need for a speciation specific analytical system. 

C5Hi202Pb, Trimethyllead acetate, 41B, 792 C5Hi202Sn, Trimethyltin(IV) acetate, 39B, 541 C5Hi3N02Sn, Glycinato(trimethyl)tin(IV), 46B, 734... 

In laboratory experiments, microorganisms in sediments from lakes are able to convert lead chloride, lead nitrate, and trimethyllead acetate to Me4Pb, and bacterial strains isolated from Lake Ontario seem to be able to convert trimethyllead acetate, but not Pb(II) salts, into tetramethyl-lead (Wong et ah 1975). The formation of Me4Pb from MegPbX is presumably not solely due to biological methylation, but also to chemical disproportionation ( Jarvie et al, 1975, Schmidt and Huber 1976) ... 

Tetraethyllead was used in the past as an antiknock agent in gasoline, but it has been phased out in most countries. Alkyllead compounds have a detergent-like activity on liposomes and black lipid membranes [232], Tributyllead destroys planar lipid membranes at lower concentrations than tripropyllead, which is again more effective than triethyl- and trimethyllead [232]. Inorganic lead compounds like lead acetate and lead nitrate were effective only at twice as high concentrations [232]. 

Fig. 1. LC—ICP-MS chromatogram of a standard mixture of organolead and inorganic lead compounds (Pb, trimethyllead and triethyllead) using reversed-phase HPLC. Mobile phase, 0.1 M ammonium acetate and 0.1 M acetic acid at pH 4.6, 30%...

Lead speciation (inorganic lead, trimethyllead chloride, triethyllead chloride, and triphenyllead chloride) has been performed by Al-Rashdan et al. [26]. Despite previous use of a gradient elution (10% to 70% methanol in water) with inductively coupled plasma atomic emission spectrometry (ICP-AES) detection, an isocratic elution was used with ICP-MS detection because gradient elution causes plasma instability. A 30% methanol/water mobile phase was used, along with a CI8 column, and the pH was optimized by using acetate buffer. 

Diacetoxy-1,1,3,3-tetrabutyldistannoxane, Sn-00360 Diazidodiphenylplumbane, Pb-00110 (l-Diazo-2-ethoxy-2-oxoethyl)trimethyllead, in Pb-00038 (l-Diazo-2-ethoxy-2-oxoethyl)trimethyltin, in Sn-00088 (Diazomethylene)bis[trimethylplumbane], see Pb-00065 (Diazomethyl)trimethylgermane, Ge-00043 (Diazophenylmethyl)trimethylgermane, see Ge-00126 Diazo(triethylgermyl)acetic acid, see Ge-00101 l-Diazo-l-(triethylgermyl)-2-propanone, Ge-00113 Diazo(trimethylplumbyl)acetic acid, Pb-00038 [Diazo(trimethylplumbyl)methyl]trimethylsilane, see Pb-00064 Diazo(trimethylstannyl)acetic acid, Sn-00088 Dibenzyldichlorostannane, Sn-00285... 

Ethylpiperidine, 7 /7-Ethyltoluene, MA radical adduct, 201 Ethyl trimethyllead diazoacetate dimethyl maleate adduct, 221 MA adduct, 221 maleic acid adduct, 221 Ethyl-o-vinyl acetal, 328... 

---