Improved access through ball milling: Octahedral Ta6 cluster alkoxides with weakly coordinating cations and a rare example of an electron‐poor Ta6 cluster

Abstract

AbstractFrom the reaction of activated (ball‐milled) [Ta6I14] with Mg‐methanolate or ethanolate the first examples of compounds with hexanuclear Ta6 units which have the octahedral edges bridged by alcoholato ligands are obtained. Either methanolato or iodido ligands are further attached to the exo sites of the Ta6 octahedra. The [Ta6(OCH3)i12(OCH3)a6]2− and [Ta6(OCH3)i12Ia6]2−/1− units were crystallized with large cations. Single crystal X‐ray diffraction studies have revealed the structures of four of these compounds. They show that the Ta−Ta atom distances are shorter than those found in comparable Ta6 halides, because of the much less pronounced matrix effect of the smaller O atoms compared to i. e. Cl. The cluster unit in (PPN)[Ta6(OC2H5)i12Ia6] comprises a rare example of an electron‐poor ensemble with 13 cluster based electrons (located in highest in energy, metal based orbitals). Differences of bond lengths between the clusters with 13 CBEs and 14 CBEs are in line with published theoretical descriptions of the bonding situation.