Shologon V. Kinetics and mechanism of oxidative addition of dimethyl sulfate and ethylene oxide to acidocomplexes of platinum (II)

The reaction of formation of platinaoxetane has been discovered and studied in detail. In neutral aqueous media the formation of platinaoxetane has been proved to proceed by a three-center cis-addition of ethylene oxide to PtCl42- metal complex. It has been shown that the reaction of MeI with PtCl3(H2O)- anion proceeds by a similar mechanism. The conditions for concerted three-centered mechanism of oxidative addition of alkylating agents to the complexes of platinum (II) have been established. In the cyclic three-center transition state of these reactions PtCl42- and PtCl3(H2O)- complexes exhibit nucleophilic and electrophilic properties simultaneously, i.e. are bifunctional in their nature. The kinetic regularities for the novel reactions of oxidative addition of protonated species of ethylene oxide or dimethyl sulfate to the complexes of platinum (II) have been ascertained. It has been shown that in the absence of affinity of platinum atom for the leaving group in the substrate the metal complex exh ibits the nucleophilic properties only. The formation of alkyl derivatives of RPtIV (R= Me, CH2CH2OH) has been proved as being due to an attack of metal complex on carbon atom in the substrate by an SN2 mechanism. The sequences of nucleophilic reactivities of platinum (II) complexes have been established.