1339764-05-4Relevant academic research and scientific papers
Chiral diamine bis(phenolate) TiIV and ZrIV complexes-synthesis, structures and reactivity
Barroso, Sonia,Adao, Pedro,Duarte, M. Teresa,Meetsma, Auke,Pessoa, Joao Costa,Bouwkamp, Marco W.,Martins, Ana M.
, p. 4277 - 4290 (2011)
Neutral and cationic titanium and zirconium diamine bis(phenolate) complexes supported by chiral ligands L1 and L2 are described [L1 = (R)-6,6′-{1-(dimethylamino)propan-2- ylazanediyl}bis(methylene)-bis(2,4-di-tert-butylphenolate);L2 = (S)-6,6′-{(1-ethylpyrrolidin-2-yl)methylazanediyl}bis(methylene)-bis(2, 4-di-tert-butylphenolate)]. Complexes[TiL(OiPr)2] [L = L1 (1), L2 (2)], [TiL2X(OiPr)] [X = Cl (3), CH2Ph (4)], [TiL1(CH2Ph)2] (5), [ZrLCl2] [L = L1 (6), L2 (7)] and [ZrL(CH2Ph) 2] [L = L1 (8), L2 (9)] are C 1-symmetric species readily prepared in moderate to high yields. Cationic compounds were obtained from complexes 5, 8 and 9 through reactions with B(C6F5)3. The monocationic species reveal the I·2-binding character of the benzyl groups and noncoordinated [B(C6F5)3(CH2Ph)] -. Complexes 5-9 were tested in the polymerization of ethylene and propylene upon activation with modified methylaluminoxane (MMAO), B(C 6F5)3 or [NHMe2Ph]+ as cocatalysts. The [ZrL1Cl2]/MMAO and [ZrL 1(CH2Ph)2]/B(C6F5) 3 systems revealed high activities in the polymerization of propylene (2.1 A- 103 and 1.5 A- 103 gpol mmolcat-1 h-1, respectively), leading to atatic polypropylene, whereas the titanium complexes showed no activity.
