Reactivity of palladium(II) methyl complexes towards CO2: formation of carbonate complexes

Treatment of a benzene solution of (tmeda)PdMe2 or (dppe)PdMe2 with carbon dioxide gives the corresponding methyl bicarbonate complex, (L–L)PdMe(O2COH). These were characterised by NMR spectroscopy and elemental analysis. Under strictly dry conditions no reaction was observed. Recrystallisation of the tmeda bicarbonate complex from acetone yields the corresponding η2-carbonate complex, which was characterised by X-ray crystallography. The reaction probably proceeds through attack by free carbonic acid on the dimethyl complex.