Low valent and mixed valent cyclopentadienyl complexes of the group 13 elements

A variety of low-coordinate bonding environments that feature group 13 elements have been explored. The highlights in this area include the isolation and structural characterization of the decamethylborocenium cation, the most tightly squeezed metallocene and the first compound to adopt a s/p geometry in the solid state, the synthesis of the first gallocenium cation, the first examples of main group constrained geometry compounds, and the first examples of multidecker p-block cations. The reactivities of monovalent group 13 pentamethylcyclopentadienide compounds with conjugated systems and electron-deficient tris(perfluorophenyl) compounds has also been explored. It has been found that [(C5Me5)M]n (M = Al, Ga) fragments will undergo oxidative addition to diazabutadienes, resulting in the formation of monomeric five-membered ring systems. Furthermore, it has been shown that the reactions of [(C5Me5)M]n clusters (M = Al, Ga) with (C6F5)3M (M = B, Al, Ga, In) yield the first examples of group 13 M(I)-M(III) donor-acceptor complexes, the first valence isomer of a dialane, and a unique inverse sandwich complex featuring p-bonding to perfluorophenyl ligands. It has further been found that the reactions of (C5Me5)2AlMe and (C5Me5)3Ga with tetramethylimidazol-2-ylidene yield unprecedented (C5Me5)2MH carbene complexes and tetramethylfulvene.