Zwitterionic Group VIII transition metal initiators supported by olefin ligands
View Patent ↗A zwitterionic Group VIII transition metal complex containing the simple and relatively small 3-(arylimino)-but-1-en-2-olato ligand that catalyzes the formation of polypropylene and high molecular weight polyethylene. A novel feature of this catalyst is that the active species is stabilized by a chelated olefin adduct. The present invention also provides methods of polymerizing olefin monomers using zwitterionic catalysts, particularly polypropylene and high molecular weight polyethylene.
1. A zwitterionic Group VIII transition metal complex containing a 3-(arylimino)-but-1-en-2-olato ligand.
2. The metal complex of claim 1 having the formula:
wherein M is a Group VIII transition metal;
R′ is a one electron hydrocarbyl;
L′ is a two electron ligand;
X′ is a two electron donor N;
each R″, R′″, and R iv is independently hydrogen, an alkyl or a substituted or unsubstituted aryl group;
R is an aryl group
n is 0;
X″ is oxygen
LA is a Lewis Acid; and
the olefin bearing X″ is bound to the metal center.
3. The metal complex of claim 1 in which:
M is nickel;
R′ is → benzyl, which represents a combination of a sigma bond and a pi-bond from the bound aromatic unit;
L′ is linked to R′
X′ is N;
R is an aryl group;
R″ is an alkyl group;
R iv is an alkyl group;
R′″ is hydrogen;
n is 0;
X″ is oxygen; and
LA is a trisubstituted boron.
4. The metal complex of claim 3 having the formula:
5. A process for polymerization or copolymerization of an olefin, comprising:
conducting the polymerization in the presence of a zwitterionic Group VIII transition metal complex containing a 3-(arylimino)-but-1-en-2-olato ligand.
6. The process of claim 5 in which the zwitterionic Group VIII transition metal complex has the formula:
wherein M is a Group VIII transition metal;
R′ is a one electron hydrocarbyl;
L′ is a two electron ligand;
X′ is N;
each R″, R′″, and R iv is independently hydrogen, an alkyl or a substituted or unsubstituted aryl group;
R is an aryl group
n is 0;
X″ is oxygen
LA is a Lewis Acid; and
the olefin bearing X″ is bound to the metal center.
7. The process of claim 6 in which:
M is nickel;
R′ is → benzyl, which represents a combination of a sigma bond and a pi-bond from the bound aromatic unit;
L′ is linked to R′
X′ is an imine;
R is an aryl group;
R″ is an alkyl group;
R iv is an alkyl group;
R′″ is hydrogen;
n is 0;
X″ is oxygen; and
LA is a trisubstituted boron.
8. The process of claim 7 in which catalyst has the formula:
9. The process of claim 5 in which the olefin is selected from the group consisting essentially of: (1) olefins having formula R v CH═CH 2 , wherein R v is hydrogen, a substituted or unsubstituted hydrocarbyl group, or a substituted or unsubstituted hydrocarbyl bearing functional group; (2) a substituted or unsubstituted cyclopentene, (3) a substituted or unsubstituted styrene, (4) a substituted or unsubstituted norbornene derivative bearing functional group, and (5) a polar olefin.
10. The process of claim 9 in which the olefin is ethylene.
11. The process of claim 9 in which the olefin is propylene.