An electron-poor di-molybdenum triple-decker with a puckered [B<inf>4</inf>Ru<inf>2</inf>] bridging ring is an oblato-closo cluster

An unprecedented, 22-valence-electron triple-decker sandwich complex [(Cp∗Mo)2{μ-η6:η6-B4H4Ru2(CO)6}], 2, has been prepared. In an effort to generate analogous triple-deckers with group 6 metal carbonyl fragments in the middle deck, we have isolated [(Cp∗MoCO)2(μ-H)2B4H4], 3, that provides the first direct evidence for the missing link between [(Cp∗MoCl)2B3H7] and [(Cp∗Mo)2B5H9] clusters.