Triisobutylaluminum: bulkier and yet more reactive towards silica surfaces than triethyl or trimethylaluminum

Abstract

Triisobutylaluminum reacts with silica yielding three different Al sites according to high-field aluminum-27 NMR and first principle calculations: a quadruply grafted dimeric surface species and two incorporated Al(O)_x species (x = 4 or 5). This result is in stark contrast to the bis-grafted species that forms during Et₃Al silica grafting. Thus the isobutyl ligands, which render R₃Al monomeric, lead to greater reactivity towards the silica surface.