A NOVEL-APPROACH FOR THE STABILIZATION AND STRUCTURAL CHARACTERIZATION OF GROUP-13 ORGANOMETALLIC HYDROXIDES - THE WAY TO WELL-DEFINED CRYSTALLINE METHYLALUMOXANES
J. Storre et al., A NOVEL-APPROACH FOR THE STABILIZATION AND STRUCTURAL CHARACTERIZATION OF GROUP-13 ORGANOMETALLIC HYDROXIDES - THE WAY TO WELL-DEFINED CRYSTALLINE METHYLALUMOXANES, Journal of the American Chemical Society, 119(32), 1997, pp. 7505-7513
The controlled hydrolysis products of R3M (M = Al, Ga; R = Mes, Ph, Me
) have been found to be stabilized by deprotonation reactions using al
kyllithium reagents. (Mes(3)Ga . OHLi). 3THF (1) and (Mes(3)Al . OHLi)
.-3THF (3) were synthesized by the reaction of LiOH with Mes(3)Ga and
Mes(3)Al, respectively. The hydroxides, (R-2- MOH)(n), resulting from
the reaction of water and R3M were deprotonated with RLi (R = Bu-t, Me
) to give (Mes(2)GaOLi)(2) . 4THF (2), (Mes(2)AlOLi)(2) . 4THF (4), (P
h2AlOLi)(3) . 6THF (5), and (Me2AlOLi)(4) . 7THF . LiCl (6). The molec
ular structures of compounds 1, 2, 4, 5, and 6 have been determined by
X-ray structure analysis. Whereas 2 undergoes metathesis reactions, c
ompounds 1, 3, 4, 5, and 6 are stable at room temperature. Compound 6
is the first structurally characterized intermediate on the pathway to
cocatalytically active methylalumoxane used in metallocene catalyzed
olefin polymerization reactions. Moreover, it represents the first str
ucturally characterized alumoxane stabilized by a separated cation.