Bimetallic Coordination Insertion Polymerization of Unprotected Polar Monomers: Copolymerization of Amino Olefins and Ethylene by Dinickel Bisphenoxyiminato Catalysts

Radlauer, Madalyn R.; Buckley, Aya K.; Henling, Lawrence M.; Agapie, Theodor

doi:10.1021/ja4004816

Cited by 172 publications

(137 citation statements)

References 64 publications

Supporting

Mentioning

132

Contrasting

Unclassified

Order By: Relevance

“…Here we report that mono-and binuclear cationic Sc halfsandwich complexes (Scheme 1B) [15] are active catalysts for ethylene copolymerization with amino olefins (AOs) in the absence of masking agents.M echanistic studies show that these catalysts exhibit distinctive catalytic behavior in comparison to group 4 [4,16] and late-transition metals, [7b] with generally higher activity and co-monomer incorporation than previously reported Ni 2 /bisphenoxyiminato catalysts. [17] Correlations between the AO linker length (n)and co-monomer selectivity support af unctional-group-assisted enchainment mechanism, with likely binuclear cooperative effects.W hile Scheme 1. Examples of mono-and binuclear catalysts for ethylene + heteroatom-functionalized olefin copolymerization.…”

mentioning

confidence: 90%

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

et al. 2017

View full text Add to dashboard Cite

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 group 4 d 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; H C=CH(CH ) NR ] copolymerizations in the absence of a Lewis-acidic masking reagent. Both activity (up to 4.2×10 kg mol ⋅h atm ) and AO incorporation (up to 12 % at 0.2 m [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.

show abstract

mentioning

confidence: 90%

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

et al. 2017

View full text Add to dashboard Cite

show abstract

“…These ketoiminate-type complexes are more NEt 3 tolerant than Grubbs-type salicylalidmine catalysts 25 and Agapie's bimetallic catalysts. 7 Unfortunately, none of these complexes catalyze ethylene copolymerization with simple molecules such as 1-octene (standard conditions, 500 equiv of 1-octene) and as such are not candidates for functional comonomer copolymerization. However, these results indicate that a deeper investigation of the functional group tolerance of ketoiminatetype ligands may be warranted.…”

Section: ■ Introductionmentioning

confidence: 99%

β-Oxo-δ-diimine Nickel Complexes: A Comparison of Tautomeric Active Species in Ethylene Polymerization Catalysis

et al. 2016

View full text Add to dashboard Cite

A series of mono-and bimetallic Ni alkyl complexes of a β-oxo-δ-diimine (BODDI) ligand are reported. The monometallic complexes have a second binding pocket, of which the free "arm" can exist as either an enamine (e.g., 8, BODEI, β-oxo-δ-enamineiminato) or imine (e.g., 3, BODII, β-oxo-δ-imineiminato) tautomer. The identity of the tautomer in the secondary Ni coordination sphere has a significant effect on ethylene polymerization behavior: the enamine tautomer, which hydrogen bonds to the central O atom and is in conjugation with the N,O backbone chelate, is significantly more electron rich and yields a much lower molecular weight polymer than the imine tautomer, which rotates away from Ni to a distal position and has little effect on polymerization. Deprotonation of the second binding pocket with M(HMDS) (M = Li, Na, K) yields the Ni-alkali metal heterobimetallic complexes 3Li, 3Na, and 3K. The deprotonated alkali metal enamides display ethylene polymerization behavior similar to the neutral imine complex because the enamide arm can also distally rotate to minimize interaction with the Ni coordination sphere upon activation. ■ INTRODUCTIONLate transition metal catalysts have been widely employed in ethylene polymerization catalysis and polar comonomer ethylene copolymerization catalysis due to their functional group tolerance. 1 The majority of functional comonomer polymerization reactions have utilized either Brookhart-type α-diimine 2 or Drent-type phosphine sulfonate 3 ligands, indicating an opportunity for continued catalysis advancement through the design of new ligand sets with new metal−ligand interactions.Akin to this, recent progress has seen several elegant examples that utilize secondary coordination sphere interactions 4 to affect various aspects of ethylene homo-and copolymerization catalysis. For example, Jordan and Bazan have each demonstrated that coordination of exogenous Lewis acids to ligands on group 10 polymerization catalysts can drastically impact polymerization activities, molecular weight distributions, and comonomer incorporation. 5 Similarly, Do recently reported on the effects of installing alkali metal cations into the secondary coordination sphere of phenoxyiminato Ni ethylene polymerization catalysts. 6 Through prudent alkali metal choice, Do was able to observe up to 20-fold increases in catalytic rates as well as significant enhancement of polymer molecular weight and branching. Transition metal bimetallic effects have also been observed; for example, Agapie reported the copolymerization of ethylene and amino olefins catalyzed by homobimetallic dinickel complexes. 7 Tethered heteroatoms usually inhibit olefin polymerization through the formation of stable chelate rings, but addition of a bulky second metal site in the secondary coordination sphere of Ni prevents stable chelate formation. Other bimetallic Fe, Ni, Cu, and early transition metal systems have shown similar cooperative effects, where addition of a second metal impacts the overall molecular weight, activity, and comonom...

show abstract

“…9 The locked conformation of these complexes allowed the isolation and purification of syn and anti atropisomers. 9a Early-metal-based dinuclear catalysts are of interest for higher activity, α-olefin incorporation, and tacticity control.…”

mentioning

confidence: 99%

Bimetallic Zirconium Amine Bis(phenolate) Polymerization Catalysts: Enhanced Activity and Tacticity Control for Polyolefin Synthesis

Radlauer

Agapie

2014

Organometallics

Self Cite

View full text Add to dashboard Cite

Binucleating multidentate amine bis(phenolate) ligands with rigid terphenyl backbones were designed to support two zirconium centers locked in close proximity. Polymerizations of propylene or 1-hexene with the synthesized bimetallic precatalysts resulted in polymers with significantly higher isotacticity (up to 79% mmmm) in comparison to the stereoirregular polymers produced with previously reported Cs-symmetric monometallic analogues. The bimetallic precatalysts also display higher activity (up to 124 kg of poly(1-hexene) (mmol of Zr)−1 h–1), in comparison to the monometallic analogues, and among the highest activities reported for nonmetallocene catalysts. The stereocontrol is consistent with a bimetallic mechanism involving remote steric interactions with the ligand sphere of the second metal center.

show abstract

Bimetallic Coordination Insertion Polymerization of Unprotected Polar Monomers: Copolymerization of Amino Olefins and Ethylene by Dinickel Bisphenoxyiminato Catalysts

Cited by 172 publications

References 64 publications

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

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

β-Oxo-δ-diimine Nickel Complexes: A Comparison of Tautomeric Active Species in Ethylene Polymerization Catalysis

Bimetallic Zirconium Amine Bis(phenolate) Polymerization Catalysts: Enhanced Activity and Tacticity Control for Polyolefin Synthesis

Contact Info

Product

Resources

About