Reaction of trimethylaluminium with main group hydroxides: a non-hydrolysis route to methylalumoxane

Abstract

Reaction of AlMe₃ with [(^tBu)₂Ga(μ-OH)]₃ or Ph₃EOH (E = Sn, Pb) yields catalytically active MAO, [MeAlO]_n, along with (^tBu)₂GaMe and Ph₃EMe, respectively, in contrast, the reaction with Ph₃EOH (E = C, Si, Ge) yields [Me₂Al(μ-OEPh₃)]₂; the formation of MAO is proposed to occur via hydroxide exchange and the formation of unstable [Me₂Al(μ-OH)]_n; the propensity towards alkane elimination versus hydroxide exchange is controlled by the relative Brønsted acidity of the main group hydroxide.