New structurally rigid palladium catalysts for the alternating copolymerization of carbon monoxide and ethene

Decreasing the flexibility of the Ph2PCH2CH2PPh2 (dppe) backbone by making the central carbon atoms part of a cyclobutane ring leads to the formation of Pd(II) catalysts for CO/ethene copolymerization that are more efficient than those of dppe by a factor of ten.