Scandium-Catalyzed Self-Assisted Polar Co-monomer Enchainment in Ethylene Polymerization

摘要

Direct coordinative copolymerization of ethylene with functionalized co-monomers is a long-sought-after approach to introducing polyolefin functionality. However, functional-group Lewis basicity typically depresses catalytic activity and co-monomer incorporation. Finding alternatives to intensively studied group4 d(0) and late-transition-metal catalysts is crucial to addressing this long-standing challenge. Shown herein is that mono- and binuclear organoscandium complexes with a borate cocatalyst are active for ethylene + amino olefin [AO; H2C=CH(CH2)(n)NR2] copolymerizations in the absence of a Lewis-acidic masking reagent. Both activity (up to 4.2x10(2)kgmol(-1)h(-1>)atm(-1>)) and AO incorporation (up to 12% at 0.2m [AO]) are appreciable. Linker-length-dependent (n) AO incorporation and mechanistic probes support an unusual functional-group-assisted enchainment mechanism. Furthermore, the binuclear catalysts exhibit enhanced AO tolerance and enhanced long chain AO incorporation.