titoli, abstracts, parole chiave >>>
Studies on the active species in olefin polymerisation generated from phenoxo-amido titanium “chiral-at-metal” compounds

Alesso, Giuseppe Andrea and Tabernero, Vanessa and Mosquera, Marta E.G. and Cuenca, Tomás (2011) Studies on the active species in olefin polymerisation generated from phenoxo-amido titanium “chiral-at-metal” compounds. Journal of Organometallic Chemistry, Vol. 696 (11-12), p. 2330-2337. ISSN 0022-328X. Article.

Full text not available from this repository.

DOI: 10.1016/j.jorganchem.2011.02.011

Abstract

Treatment of RHN-CH2-(3,5-tBu2C6H2-2-OH) (R = C6H5 1a, p-MeC6H4 1b, Cy 1c; Cy = cyclohexyl) with 1 equiv of TiCp*Cl3 (Cp* = η5-C5Me5) in the presence of 2.5 equiv of NEt3 in pentane or hexane at room temperature gives the monocyclopentadienyl phenoxo-amido monochloro complexes [TiCp*{RN-CH2-(3,5-tBu2C6H2-2-O)}Cl] (R = C6H5 2, p-MeC6H4 4, Cy 5). In a more polar solvent the phenoxo-amino complex [TiCp*{(C6H5)(H)N-CH2-(3,5-tBu2C6H2-2-O)}Cl2] (3) is obtained from the reaction with 1a. The reaction of TiCp*Cl3 with tBu(H)N-CH2-(3,5-tBu2C6H2-2-OH) (1d) affords the complex [TiCp*{tBu(H)N-CH2-(3,5-tBu2C6H2-2-O)}Cl2] (6) in which no coordination of the amino group to the metal centre is observed as a consequence of the high steric requirements of the amino substituent in the phenol-amine. All the reported compounds were characterised by the usual analytical and spectroscopic methods and the molecular structures of 2 and 5 were determined by X-ray diffraction analysis from suitable single crystals.Studies of catalytic activity for ethylene or propylene polymerisation using boron or aluminium reagents as cocatalysts were performed under different conditions. In general the trends observed for the phenoxo-amido precatalysts with the aluminium reagent as cocatalyst in the α-olefin polymerisation reactions might suggest a catalyst decomposition process through ligand abstraction by sMAO. The activity found for ethylene or propylene polymerisation when B(C6F5)3 or [CPh3][B(C6F5)4] are used as cocatalysts is related to the strength of the cation-anion interactions.

Item Type:Article
ID Code:5753
Status:Published
Refereed:Yes
Uncontrolled Keywords:Titanium, phenoxo-amido, phenoxo-amino, asymmetric metal centre
Subjects:Area 03 - Scienze chimiche > CHIM/03 Chimica generale e inorganica
Divisions:001 Università di Sassari > 01 Dipartimenti > Chimica
Publisher:Elsevier
ISSN:0022-328X
Deposited On:11 May 2011 10:53

I documenti depositati in UnissResearch sono protetti dalle leggi che regolano il diritto d'autore

Repository Staff Only: item control page