Platinum—lead bonds reactions with

Platinum removes a halogen atom from the halide, causing homolytic fission of the C-halogen bond. The resulting Pt -XR radical pair can either react to form Ptn(R)X or separate, with subsequent reaction with RX leading to either PtX2 or PtRX species or reaction with solvent molecules. 

Platinum-lead complexes undergo a cleavage of Pt—Pb bond with halogens and halogen acids506,507 510. These reactions are believed to occur through an electrophilic attack on Pt(II) leading to oxidative addition with the formation of a hexa-coordinated Pt(IV) complex. Reductive elimination of a plumbane results in the observed products (equation 193). 

Similar to the addition of halogens, cycloproparenes react under hydrogenation conditions either by initial attack at the cyclopropene bond or via cleavage of one of the lateral cyclopropane bonds. In the former case, the intermediate norcaradiene opens to a cycloheptatriene which is further reduced to cycloheptane. In the latter, the reduction leads to toluene or methyl-cyclohexane. For example, benzocyclopropene, on reaction with platinum oxide in acetic acid, was hydrogenated to cycloheptane (49%) and methylcyclohexane (51%). 1,1-Difluoroben-zocyclopropene, under the same conditions, gave cycloheptane exclusively (85%). Hydrogenation of benzocyclopropene with Raney nickel gave toluene in 90% yield. 

Thus, it can be concluded that reactions, in which there is a possibility of the formation of platinum(IV) derivatives with alkyl fragments containing a hydrogen bond in the p-position, lead to olefin ff-cotnp exes of platinum(II). These reactions are the interactions of platinum chlorides with alkyl iodides and alkyl derivatives of tin as well as the thermal and photochemical dehydrogenation of n-hexane by PtCU (Scheme VI.5). One possible mechanism for the dehydrogenation of n-hexane is the formation of a cr-hcxyl complex of plati-num(IV) and its subsequent transformation into a n-olefin complex of plati-num(II) via p-elimination of hydrogen [16] ... 

A trispyrazolylborate platinum complex was found to activate C-H bonds via a Pt(ii)/Pt(iv) sequence. Removal of a methyl anion from [(77 -Tp )RhMe2] leads to an unsaturated species that then adds to the hydrocarbon C-H bond (Equation (12)). The related protonatcd species Tp PtMc2H loses methane at 110°G and then oxidatively adds benzene- 6. The new methyl-phenyl-deuteride derivative then reversibly exchanges deuterium into the methyl group, indicating reversible methane activation. In addition, the Pt-H bond can undergo reaction with oxygen to... 

In many other cases, oxidative additions of alkanes occur readily to transition-metal-alkyl complexes to generate hydride dialkyl intermediates that subsequently eliminate alkane and form a new metal-alkyl complex. For example, cations related to the alkyl hydrides of iridium formed by oxidative addition undergo reaction with alkanes at or below room temperature to generate new alkyl complexes (Equation 6.34). Cationic platinum complexes undergo similar reactions with substrates containing aromatic and aliphatic C-H bonds (Equation 6.35). " The C-H activation of the platinum complexes has been studied, in part, to understand and to develop systems related to the ones reported by Shilov that lead to H/D exchange, and oxidation and halogenation of alkanes. 

---