Synthesis, characterization and catalytic activity of the complex titanium bis(dimethylmalonate)-bis(diethylamido) in the polymerization of propylene

TY - JOUR

T1 - Synthesis, characterization and catalytic activity of the complex titanium bis(dimethylmalonate)-bis(diethylamido) in the polymerization of propylene

AU - Gueta-Neyroud, Tal

AU - Tumanskii, Boris

AU - Botoshansky, Mark

AU - Eisen, Moris S.

N1 - Funding Information: This research was supported by the USA–Israel Binational Science Foundation under Contract 2004075. B.T. thanks the Center for Absorption in Science, Israel Ministry of Immigrant Absorption, State of Israel.

PY - 2007/2/1

Y1 - 2007/2/1

N2 - In this account we present the synthesis, characterization and catalytic activity in the polymerization of propylene of a bis(dimethyl malonate) titanium bis(diethylamine) complex (1). The complex exhibits in solution a dynamical isomerization following an internal Bailar twist. The activation of complex 1 was obtained by its reaction with methylalumoxane (MAO). The activated complex in solution shows a different dynamic process involving an equilibrium between a monodentate η1 and bidentate η2 binding of the dimethylmalonate ligand to the metal center. This equilibrium is responsible for the formation of, at least, two active species for the polymerization reaction bearing major symmetry differences. The monodentate coordination (opened form) of the ligand was found to be the major form of the active species of the complex when activated with MAO, most probably due to a strong interaction of the oxygen atoms in the ligand with the strong Lewis acid co-catalyst. The active species in the polymerization were studied by NMR and ESR spectroscopies. The resulting polypropylene showed elastomeric properties with low tacticites.

AB - In this account we present the synthesis, characterization and catalytic activity in the polymerization of propylene of a bis(dimethyl malonate) titanium bis(diethylamine) complex (1). The complex exhibits in solution a dynamical isomerization following an internal Bailar twist. The activation of complex 1 was obtained by its reaction with methylalumoxane (MAO). The activated complex in solution shows a different dynamic process involving an equilibrium between a monodentate η1 and bidentate η2 binding of the dimethylmalonate ligand to the metal center. This equilibrium is responsible for the formation of, at least, two active species for the polymerization reaction bearing major symmetry differences. The monodentate coordination (opened form) of the ligand was found to be the major form of the active species of the complex when activated with MAO, most probably due to a strong interaction of the oxygen atoms in the ligand with the strong Lewis acid co-catalyst. The active species in the polymerization were studied by NMR and ESR spectroscopies. The resulting polypropylene showed elastomeric properties with low tacticites.

KW - Catalysis

KW - Dimethylmalonate

KW - Elastomeric propylene

KW - Group 4

KW - Polymerization

KW - Titanium

KW - Ziegler-Natta

UR - http://www.scopus.com/inward/record.url?scp=33846489177&partnerID=8YFLogxK

U2 - 10.1016/j.jorganchem.2006.10.031

DO - 10.1016/j.jorganchem.2006.10.031

M3 - 文章

AN - SCOPUS:33846489177

SN - 0022-328X

VL - 692

SP - 927

EP - 939

JO - Journal of Organometallic Chemistry

JF - Journal of Organometallic Chemistry

IS - 5

ER -