Copolymerization of Ethylene and Vinyl Fluoride by Self-Assembled Multinuclear Palladium Catalysts.

The self-assembled multinuclear Pd complexes {(Li-OPO)PdMe(4-5-nonyl-pyridine)}LiCl (, Li-OPO = PPh(2-SOLi-4,5-(OMe)-Ph)(2-SO-4,5-(OMe)-Me-Ph)), {(Zn-OP-P-SO)PdMe(L)} (, L = pyridine or 4-Bu-pyridine, [OP-P-SO] = P(4-Bu-Ph)(2-PO-5-Me-Ph)(2-SO-5-Me-Ph)), and {(Zn-OP-P-SO)PdMe(pyridine)} () copolymerize ethylene and vinyl fluoride (VF) to linear copolymers. VF is incorporated at levels of 0.1-2.5 mol% primarily as in-chain -CHCHFCH- units. The molecular weight distributions of the copolymers produced by and are generally narrower than for catalyst , which suggests that the Zn-phosphonate cores of and are more stable than the Li-sulfonate-chloride core of under copolymerization conditions. The ethylene/VF copolymerization activities of - are over 100 times lower and the copolymer molecular weights (MWs) are reduced compared to the results for ethylene homopolymerization by these catalysts.