Patent ID: 7087690

Claim:
A process for the stereospecific polymerization of an alpha-olefin, comprising polymerizing at least one alpha-olefin in the presence of a catalyst composition, optionally in the presence of one or more activators, under polymerization conditions, wherein the catalyst composition is formed from a mixture which comprises: (1) a ligand characterized by the following general formula: wherein R 1 is characterized by the general formula: wherein E is either carbon or nitrogen, Q 1 and Q 5 are substituents on the R 1 ring at a position ortho to E, with Q 1 and Q 5 are independently selected from the group consisting of alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, aryl, substituted aryl and silyl, but provided that Q 1 and Q 5 are not both methyl; Q″ q represents additional possible substituents on the ring, with q being 1, 2, 3, 4 or 5 and Q″ being selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heteroalkyl, substituted heteroalkyl, heterocycloalkyl, substituted hetercycloalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, alkoxyl, aryloxyl, silyl, boryl, phosphino, amino, thio, seleno, halide, nitro, and combinations thereof; T is a bridging group selected group consisting of —CR 2 R 3 — and —SiR 2 R 3 — with R 2 selected from the group consisting of hydrogen, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heteroalkyl, substituted heteroalkyl, heterocycloalkyl, substituted hetercycloalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, alkoxyl, aryloxyl, silyl, boryl, phosphino, amino, thio, seleno, halide, nitro, and combinations thereof; R 3 selected from the group consisting of aryl, substituted aryl, heteroaryl, and substituted heteroaryl; and provided that R 2 is different from R 3 ; J″ is selected from the group consisting of heteroaryl and substituted heteroaryl; (2) a metal precursor compound characterized by the general formula M(L) n wherein M is either hafnium or zirconium and each L is independently selected from the group consisting of halide, alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl, heteroalkyl, substituted heteroalkyl heterocycloalkyl, substituted heterocycloalkyl, aryl, substituted aryl, heteroaryl, substituted heteroaryl, alkoxy, aryloxy, hydroxy, boryl, silyl, amino, amine, hydrido, allyl, diene, seleno, phosphino, phosphine, carboxylates, thio, 1,3-dionates, oxalates, carbonates, nitrates, sulphates, ethers, thioethers and combinations thereof or optionally two or more L groups are joined into a ring structure; n is 1, 2, 3, 4, 5, or 6; and (3) optionally, at least one activator.