Air And Moisture Tolerant Synthesis Of A Chelated Bis(Nhc) Methylpalladium(Ii) Complex Relevant To Alkyl Migration Processes In Catalysis

An air- and moisture-tolerant alternate synthetic pathway to the preparation of a cationic chelated bis(NHC) methylpalladium(II) complex, [{(MesIm)(2)CH2}Pd(Me)(NCMe)][PF6], is described. The pathway involves the isolation of a bis(NHC) AgI complex, [{(MesIm)(2)CH2}(2)Ag-2][PF6](2), via metallation of the corresponding diimidazolium salt with Ag2O followed by carbene transfer to [(COD)PdBrMe]. This newmethod avoids a previously reported unstable intermediate that displayed rapid decomposition at room temperature, attaining the targeted cationic methylpalladium(II) complex in high yield. CO/ethylene copolymerisation catalysis trials are reported showing solvent dependent catalyst lifetime and copolymer yields. Preliminary ethylene insertion studies are also outlined revealing possible pathways leading towards catalyst deactivation.