The synthesis of a zwitterionic Pd(II) complex supported by an anionic bis(phosphino)borate ligand, Ph2B(CH2PPh2)2 (abbreviated as [Ph2BP2]), is reported. The new complex, [Ph2BP2]PdMe(THF), is active for CO and ethylene copolymerization. The copolymerization activity and polyketone molecular weight for the neutral, zwitterionic system are compared with those for the cationic systems [R2E(CH2PPh2)2PdMe(THF)][B(C6F5)4] where ER2 = SiPh2 and CH2. Surprisingly, the more electron rich zwitterionic system is a catalyst of activity comparable to that of the more conventional cationic systems.
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