852447-91-7Relevant academic research and scientific papers
Neutral and cationic aluminum and titanium complexes incorporating sterically demanding organosilicon ligands
Amo, Virginia,Andres, Roman,De Jesus, Ernesto,De La Mata, F. Javier,Flores, Juan C.,Gomez, Rafael,Gomez-Sal, M. Pilar,Turner, John F. C.
, p. 2331 - 2338 (2008/10/09)
New complexes of aluminum and titanium containing sterically demanding ligands and their reaction with B(C6F5)3 are reported. Treatment of [(Ph2MeSiCH2CH2) 3Si]NCN[Si(CH2CH2SiMePh2) 3] (1) or Si(CH2CH2SiMePh2) 3OH (2) with 1 equiv of AlMe3 results in the formation of the neutral dimethylaluminum complexes {MeC[NSi(CH2CH 2SiMePh2)3]2}AlMe2 (3) and [(Ph2MeSiCH2CH2)3SiOAlMe 2]2 (4). Reaction of 3 with 1 equiv of B(C 6F5)3 forms the neutral complex {MeC[NSi(CH2CH2SiMePh2)3] 2}AlMe(C6F5) (5) and BMe(C6F 5)2. In the case of 4, the analogous reaction produced the dimer [(Ph2MeSiCH2CH2)3SiOAl] 2Me3(C6F5) (6). Treatment of 1 with Ti(C5Me5)Me3 fails to afford the corresponding amidinate complex. However, reaction of 2 with the same titanium half-sandwich complex cleanly gives Ti(C5Me5)[OSi(CH2CH 2SiMePh2)3]Me2 (7). Reaction of 7 with 1 equiv of B(C6F5)3 leads to the formation of the ion pair {Ti(C5Me5)[OSi(CH2CH 2SiMePh2)3]Me}[BMe(C6F 5)3] (8), which is relatively stable at room temperature, slowly decomposing (t1/2 ≈ 48 h) to give a mixture of two neutral titanium complexes, Ti(C5Me5)[OSi(CH2CH 2SiMePh2)3][CH2B(C6F 5)2](C6F5) (9) and TiC 5Me5)[OSi(CH2CH2SiMePh 2)3]Me(C6F5) (10). However, when this reaction is carried out in a 1:0.5 stoichiometry, the decomposition process occurs over the course of 22 h, giving complex 10 selectively. The implications of these results with related Ziegler-Natta catalyst systems are discussed.
