[K([18]crown‐6)]+ [Mo4(μ4‐H) (OCH2tBu)12]−, the First Alkoxidohydrido Cluster of Molybdenum, Evidence for a Rare, if not the First, Example of a μ4‐Hydride

A Mo4 butterfly cluster in which a hydrido ligand is bonded to all four metal atoms probably occurs in the anion of the title complex. This anion is accessible from [Mo2(OCH2tBu)6] and K[BsBu3H] in the presence of [18]crown-6. As shown schematically below the H-ligand serves to couple two Mo  Mo units to generate the Mo4(μ4-H)-containing anion.