Metalloborane cluster compounds

Recent work has shown that most transition metals and post-transition metals can be incorporated as vertices in polyhedral metalloborane cluster compounds. Numerous synthetic routes have been devised and structural studies on the resulting clusters have revealed an astonishing variety of geometrical forms. Most boranes and borane anions from B2 to B12 now have metalloborane analogues in which one or more of the various boron atoms in the cluster of the parent borane are replaced by a metal centre. In addition, the flexibility introduced into the bonding by the differing connectivities, coordination numbers, and oxidation states of the various metals enables many unprecedented clusters to be generated. Examples of these novel cluster geometries include con juncto[ (PMe2Ph) 2 (Pt2B8H14)J, con juncto[ (PMe2Ph) 2 (Pt2B12H18) 1, iso—nido{ (PPh3) 2 (IrB9H10 .PPh3) 1, iso—closo-[H(PPh3) (PPh2a6H4) (Ir9H8) 1, iso—closo-[H(PMe3) 2(IrB8H7C1) 1, con juncto{ (PMe2Ph) (PtB16H18 . PMe2Ph) 1, and several conjuncto-PtB18 and -Pt2B18 species some of which feature the construction by cluster rearrangement of an unusual confacial triangular fusion between the two subclusters.