Et(2)Al(+) alumenium ion-like chemistry. synthesis and reactivity toward alkenes and alkene oxides.

Inert weakly coordinating carborane anions, CB(11)H(6)X(6)(-) (X = Cl, Br), allow access to the long sought, highly electrophilic diethylaluminum moiety in Et(2)Al(CB(11)H(6)X(6)). X-ray crystallography reveals ion-like structural features reminiscent of the corresponding trialkylsilylium species. Et(2)Al(CB(11)H(6)X(6)) is a potent catalyst for the electrophilic ethenation of benzene, the polymerization of cyclohexene oxide, and the oligomerization of ethene to a low molecular weight, highly branched product.