Terminal Alkyne Activation by an Al(I)-Centered Anion: Impact on the Mechanism of Alkali Metal Identity

The group 1 alumanyls, [{SiNDipp}AlM]2 (M = K, Rb, Cs; SiNDipp = {CH2SiMe2NDipp}2), display a variable kinetic facility (K Dipp}AlM]2 dimers, the integrity of which reflects the ability of M+ to maintain the polyhapto group 1-arene interactions necessary for dimer propagation. These observations highlight that such “on-dimer” reactivity takes place sequentially and also that the ability of each constituent Al(I) center to effect the activation of the organic substrate is kinetically differentiated.