Water-Soluble Palladium(II) Catalysts for the Alternating Co- and Terpolymerization of CO and Olefins in Aqueous Phase

The water-soluble diphosphine (NaO3S(C6H4)CH2)2C(CH2PPh2)2 (Na2DPPPDS) was employed to prepare the bis-trifluoroacetate Pd(II) complex Pd(Na2DPPPDS)(CO2CF3)2·2THF (1). The catalytic performance of 1 in the co- and terpolymerization of CO and ethene and propene in water has been studied in different experimental conditions. In combination with both a protic acid, commonly p-toluenesulfonic acid, and an organic oxidant such as 1,4-benzoquinone, 1 forms the most efficient catalyst systems ever reported for the copolymerization of CO and ethene in water. Under comparable conditions, the activity of 1 is similar to that of the industrial Pd(II) 1,3-bis(diphenylphosphino)propane catalysts in MeOH. Unlike the latter which yield a mixture of copolymers bearing diketone, keto-ester, or diester end groups, the copolymers and terpolymers produced with the Na2DPPPDS-based catalysts have exclusively ketonic end groups for average molecular weights ranging from 10 to 30 kg mol-1 depending on the reaction conditions. In...