Organoleads formation

There is general agreement that static-bomb combustion calorimetry is inherently unsatisfactory to determine enthalpies of formation of organolead compounds2,3. Unfortunately, as shown in Table 6 only three substances have been studied by the rotating-bomb method. The experimentally measured enthalpies of formation of the remaining compounds in Table 6 were determined by reaction-solution calorimetry and all rely on AH/(PbPh4, c). 

TABLE 6. Standard enthalpies of formation of organolead compounds (kJ mol 1)... 

Determination of organolead metabolites of tetraalkyllead in urine can be carried out after solid-phase enrichment and end analysis using reversed-phase HPLC with chemical reaction detector and by LC-MS (thermospray127). The chemical derivation consists of conversion to the dialky Head form, as shown in reaction 1, followed by complex formation with 4-(2-pyridylazo)resorcinol (11) and spectrophotometic measurement at 515 nm128. 

Further disproportionation reaction is important in organolead chemistry. As reported in Section m. C, tetraorganylplumbanes were obtained by reacting PbCl2 with organometal-lic compounds via the intermediates PbR2. The processes were accompanied by cleavage and formation of C—Pb and Pb—Pb bonds as described by equations 22 and 23. 

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