C1-symmetric tert-butyl substituted pyridylamido hafnium complex for ethylene, α-olefin, and styrene polymerizations

Hafnium and Zirconium Complexes Bearing ONN-Tridentate Ligands and Their Catalytic Properties toward Olefin Polymerization

“…On the other hand, group 4 metal complexes based on NN-bidentate ligands, such as pyridyl-amido (Chart , B ), imino-amido (Chart , C ), , imino-enamido (Chart , D ), , amido-quinoline (Chart , E ), , and amido-trihydroquinoline (Chart , F ), are very attractive for high-temperature solution-phase olefin polymerization processes to prepare polyolefin elastomers (POEs) with high activity, high molecular weight, and adjustable incorporation of a comonomer . In addition, the Hf complex bearing a tridentate CNN-ligand (Chart , G ) based on the pyridyl-amido framework was developed by the high-throughput screening method in the collaboration of Dow and Symyx. − This tridentate CNN-coordinated Hf complex can undergo reversible chain transfer with ZnEt 2 and has been used to synthesize olefin block copolymers (OBCs) in combination with a second FI–Zr catalyst. ,− …”

Theoretical Elucidation of the Effect of Counteranions on the Olefin Polymerization Activity of (Pyridylamido)Hf(IV) Catalyst by QM and REMD Studies: MeB(C6F5)3– versus B(C6F5)4–

“…This catalyst has recently been utilized in a new polymerization technology, chain shuttling polymerization (CSP), − where ethylene/1-octene multiblock copolymers can be obtained by introducing a chain transfer agent into a solution mixture of two catalyst species with different 1-octene incorporation abilities. Hence, a lot of mechanistic studies − and ligand modifications − of (pyridylamido)­Hf­(IV) catalyst have been conducted so far.…”

Copolymerization of Ethylene with Selected Vinyl Monomers Catalyzed by Group 4 Metal and Vanadium Complexes with Multidentate Ligands: A Short Review

“…One of the interesting classes of postmetallocene catalysts are catalysts based on pyridylamido hafnium complexes which were shown to have high incorporation ability in ethylene/1-olefin copolymerization at high temperature [44][45][46]. C 1 -symmetric tert-butyl substituted pyridylamido hafnium complex Hf-6 activated with Ph 3 CB(C 6 F 5 ) 4 /Al(iBu) 3 was able to incorporate 6.0 mol% of 1-octene and 8.7 mol% of 1-hexene in ethylene/ 1-olefin copolymerization carried out with the addition of 0.1 mol of comonomer, at 80 • C for 10 min under 10 atm of ethylene.…”

“…C 1 -symmetric tert-butyl substituted pyridylamido hafnium complex Hf-6 activated with Ph 3 CB(C 6 F 5 ) 4 /Al(iBu) 3 was able to incorporate 6.0 mol% of 1-octene and 8.7 mol% of 1-hexene in ethylene/ 1-olefin copolymerization carried out with the addition of 0.1 mol of comonomer, at 80 • C for 10 min under 10 atm of ethylene. The produced copolymers had broad MWD with bimodal distribution and high molecular weight equal to 262,000 g/mol and 931,000 g/mol (copolymer with 1-octene and 1-hexene, respectively) [44]. Selected results of ethylene/ 1-olefin copolymerization with group 4 metal complexes are displayed in Table 4.…”