2,2′‐thiobis(6‐tert‐butyl‐4‐methylphenoxy)titanium or zirconium complex‐methylalumoxane catalysts for polymerization of olefins

Alkylmono(cyclopentadienyl)titanium Complexes Containing the 2,2′‐Methylenebis(6‐tert‐butyl‐4‐methylphenoxido) Ligand – Studies on the Nature of the Catalytic Species Present in α‐Olefin Polymerisation Processes

“…The former occurs by replacement of the halo groups in the precursor with alkyl groups and then abstraction of one of these alkyl groups to give cationic alkyl species, which are considered to be the active species in the process. As our neutral species with general formula [TiCl(η 5 1 H NMR spectroscopic analysis revealed complex 4 to be essentially the only reaction product, thereby indicating alkylation of the Ti-Cl bond and selective formation of the methyl derivative. The NMR spectra also show the presence of traces of signals assignable to secondary products containing the bis(phenoxido) ligand.…”

“…[3] [TiCl 2 (mbmp)] [106.5(2)°], [18] [TiMe 2 (mbmp)] [112.7(2)°], [18] [Ti(mbmp)(BH 4 ) 2 ] [103.9(2)°], [19] and the mono(cyclopentadienyl)bis(phenoxido)titanium complexes [CpTiX(OC 6 H 3 -iPr 2 ) 2 ] [X = Cl, tBu and Me; 103.0(3)°, 107.7(9)°and 109.0(5)°, respectively]. [20] The dihedral angles between both phenyl rings are 115.92(19)°and 115.52 (18)°, more open than those found for analogous ligands with different bridging units {S in tmbp and Te in tebp [tmbp = 2,2Ј-thiobis(6-tert-butyl-4-methylphenoxido), tebp = 2,2Ј-tellurobis(6-tert-butyl-4-methylphenoxido)]; [Ti(mbmp)(BH 4 ) 2 ] = 64.1(2)°, [19] [TiCl 2 (mbmp)(thf)] = 113.4(3)°, [21] [TiCl 2 (tmbp)] 2 = 102.9(3)°, [5] …”

“…1.791(2) Å], [21] [TiCl 2 (tmbp)] 2 [av. 1.818(4) Å], [5] [TiCl 2 (tebp)] 2 [av. 1.801(9) Å], [15] [CpTiCl(tmbp)] [av.…”

“…[1][2][3] Alkoxidotitanium and -zirconium compounds combined with a co-catalyst (MAO) are highly active catalysts in α-olefin polymerisation. [4][5][6][7][8][9] The synthesis of dialkyl(alkoxido) de- rivatives of group 4 elements is very difficult as they are sensitive to atmospheric moisture and to light. The reaction of [MR 4-x (OAr) x ] complexes with the Lewis acid B(C 6 F 5 ) 3 has been reported to give the zwitterionic species [M(CH 2 Ph)(OAr) 2 ][B(η 6 -C 6 H 5 CH 2 )(C 6 F 5 ) 3 ] for the benzyl derivatives and a mixture of [Ti(C 6 F 5 )Me(OAr) 2 ] and BMe(C 6 F 5 ) 2 for the methyl complexes.…”

Ethylene‐Norbornene Copolymerization by New Titanium Complexes Bearing Tridentate Ligands. Sidearm Effects on Catalytic Activity

“…[4][5][6][7][8][9] These bis-ligated species of the type [O À N] 2 MCl 2 are excellent pre-catalysts for olefin polymerization including ethylene living polymerization, [5,6] highly syndiospecific propene living polymerization, [7] living copolymerization of ethylene with a-olefin, [8] and for the synthesis of functional block copolymers. [9] In view of the advantages of phenoxy-imine backbone [4][5][6][7][8][9] and the role of pendant heteroatom groups in catalysis, [10][11][12] we have designed a number of tridentate…”