[ONXO]-Type Amine Bis(phenolate) Zirconium and Hafnium Complexes as Extremely Active 1-Hexene Polymerization Catalysts
作者:Edit Y. Tshuva、Stanislav Groysman、Israel Goldberg、Moshe Kol、Zeev Goldschmidt
DOI:10.1021/om010493w
日期:2002.2.1
demonstrated. The high activity of the complexes is derived from the binding of the side-arm donor to the metal and is affected by its nature. The activity order of the zirconiumcomplexes as a function of the side-arm donor was found to be OMe > NMe2 > SMe (5:2:1). The X-ray structures of all zirconiumcomplexes were solved and revealed very similar binding of the [ONO] ligand cores to the metal. The distances
Synthesis and characterization of binuclear [ONXO]-type amine-bis(phenolate) copper(II) complexes
作者:Elham Safaei、Maryam Rasouli、Thomas Weyhermüller、Eckhard Bill
DOI:10.1016/j.ica.2011.04.048
日期:2011.9
Dimeric copper(II) complexes [(Cu2L2)-L-II] of a series of amine-bis(phenolate) ligands (H2L) bearing different non- or weakly coordinating side-arms such as ethyl (H2LEt), n-butyl (H2LBu), thiomethyl (H2LSMe) and hydroxyl (H2LOH) were synthesized. They were characterized by X-ray crystallography, UV-Vis, IR and magnetic susceptibility measurements. X-ray analysis revealed complexes in which Cu(II) centers are surrounded by three phenolate oxygen atoms, an amine nitrogen atom and thiomethyl and hydroxyl coordinating groups in Cu2L2SMe and Cu2L2OH, respectively. Two phenolate bridges hold both copper atoms together to form binuclear [(Cu2L2)-L-II] complexes. To the best of our knowledge, Cu center dot center dot center dot Cu distances and Cu-O-Cu bridge angles of these complexes are the smallest values, which have been reported for phenoxo-bridged copper complexes to date. Phenolate moieties of the copper complexes can be electrochemically oxidized to phenoxyl radicals. Magnetic studies show that Cu2L2Et and Cu2L2Bu are rare examples of phenolato-bridged Cu(II) dimer exhibiting ferromagnetic interaction (J = +26.62 and +38.65 cm (1) respectively). In addition, an antiferromagnetic exchange with J values of -65.88 and -2.77 cm (1) was found for Cu2L2SMe and Cu2L2OH, respectively. (C) 2011 Elsevier B.V. All rights reserved.
Effects of Pendant Ligand Binding Affinity on Chain Transfer for 1-Hexene Polymerization Catalyzed by Single-Site Zirconium Amine Bis-Phenolate Complexes
作者:D. Keith Steelman、Silei Xiong、Paul D. Pletcher、Erin Smith、Jeffrey M. Switzer、Grigori A. Medvedev、W. Nicholas Delgass、James M. Caruthers、Mahdi M. Abu-Omar
DOI:10.1021/ja401474v
日期:2013.4.24
distance elongates further, as is the case for catalysts 4 and 5, which operate primarily through a different mechanistic pathway. These findings underscore the importance of comprehensive kinetic modeling using a diverse set of multiresponse data, enabling the determination of robust kineticconstants and reaction mechanisms of catalytic olefinpolymerization as part of the development of structure-activity