Controlled Pd(0)/ t -Bu ₃P-catalyzed suzuki cross-coupling polymerization of AB-type monomers with PhPd(t -Bu ₃P)I or Pd ₂(dba) ₃/ t -Bu ₃P/ArI as the initiator

Controlled Pd(0)/t-Bu ₃P-catalyzed Suzuki cross-coupling polymerizations of AB-type monomers via the chain-growth mechanism with an ArPd(t-Bu ₃P)I complex as the initiator are described. ArPd(t-Bu ₃P)I complexes, either prepurified or generated in situ from Pd ₂(dba) ₃/t-Bu ₃P/ArI (dba = dibenzylideneacetone) without separation/purification, were found to be efficient initiators in general for the controlled Suzuki cross-coupling polymerization, with narrow polydispersity indexes (PDIs) of 1.13-1.35 being observed. The Pd ₂(dba) ₃/t-Bu ₃P/p-BrC ₆H ₄I combination was identified as a highly robust initiator system, with PDIs of ≤1.20 in general and as low as 1.13 being obtained. Higher number-average molecular weights (M _n) were achieved without a significant increase in the PDI (from 1.14 for a polymer with a M _n = 9500 to 1.20 for a polymer with M _n = 31 400) by using a smaller amount of the Pd ₂(dba) ₃/t-Bu ₃P/p-BrC ₆H ₄I initiator in the polymerization.