Transition metal catalysts for olefin polymerization
In one aspect, a chelating phosphine-phosphonic diamide (PPDA) ligand is described herein for constructing transition metal complexes operable for catalysis of olefin polymerization, including copolymerization of ethylene with polar monomer.
1. A method of polymerization comprising:
providing a reaction mixture including olefin monomer, polar monomer and transition metal complex of Formula (II):
wherein M is a transition metal, A is selected from the group consisting of alkylene, alkenylene, arylene and heteroarylene, and wherein R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are independently selected from the group consisting of alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, alkyl-aryl and alkyl-heteroaryl, wherein R 1 and R 2 optionally form a ring structure and any combination of R 3 , R 4 , R 5 and/or R 6 optionally form a ring structure and wherein R 7 is selected from the group consisting of alkyl and aryl and R 8 is selected from the group consisting of amine, heteroaryl, monophosphine, halo and sulfoxide and wherein X − is a non-coordinating counter anion; and
copolymerizing the olefin monomer with the polar monomer in the presence of the transition metal complex.
2. The method of claim 1 , wherein the polar monomer is selected from the group consisting of acrylic acid, alkyl acrylic acids, alkyl acrylates, acetates, acrylamide, vinyl ethers and/or acrylonitrile.
3. The method of claim 2 , wherein the olefin monomer is ethylene or propylene.
4. The method of claim 1 , wherein M is palladium.
5. The method of claim 1 , wherein M is nickel.
6. The method of claim 1 , wherein copolymer resulting from the copolymerization has molecular weight (M w ) of at least 5,000 Da.
7. The method of claim 1 , wherein copolymer resulting from the copolymerization has molecular weight (M w ) of at least 10,000-200,000 Da.
8. The method of claim 1 , wherein at least 50 percent of the polar monomer in the copolymer is incorporated in-chain.
9. The method of claim 1 , wherein at least 90 percent of the polar monomer in the copolymer is incorporated in-chain.
10. The method of claim 1 , wherein the polar monomer is exclusively incorporated in-chain.
11. The method of claim 1 , wherein M is palladium or nickel, A is arylene, R 1 -R 2 are independently aryl, R 3 -R 6 are independently alkyl, R 7 is selected from alkyl and aryl and R 8 is selected from the group consisting of heteroaryl, halo and sulfoxide.
12. The method of claim 1 , wherein 3-15 mol. % polar monomer is incorporated into the copolymer.
13. The method of claim 8 , wherein 5-15 mol. % polar monomer is incorporated into the copolymer.