Use of a structurally characterized molecular cluster to form Yb 3 Al 5 O 12 under ambient conditions

Abstract

The synthesis and structure of the novel octametallic cluster [{Yb₄(µ₄-O)(µ₂-OPrⁱ)₂(µ₂-Me)₄}{(µ₂-Me)(µ₂-OⁱPr)AlMe₂}₄] 1 and its use to form Yb₃Al₅O₁₂ under ambient conditions is reported. The compound was formed by combining AlMe₃ with 99.8% pure Yb(OⁱPr)₃. Nevertheless, the compound has similarities with the known hydrolysis product Yb₅(O)(OⁱPr)₁₃, including a central Yb_n-µ_n-oxide. In the structure each AlMe₂ unit is joined to an ytterbium atom by bridging Me and OⁱPr groups in a manner that is observed for many other aluminum – lanthanide alkoxides. What is unprecedented for lanthanide oxide – alkoxide clusters, however, is the bridging of each pair of Yb atoms by two Me groups. The use of 1 to form Yb₃Al₅O₁₂ is an indication that oxophilic mixed-metal oxide clusters that contain extensive metal – oxygen connectivity may be predisposed to hydrolyze to the mixed-metal oxide solid-state material. This concept was established previously for the aluminum-only Mitsubishi molecules [Al{µ-OEt)₂AlR₂}₃], which are converted into nanoparticulate alumina by exposure of hexane solutions of the molecule to moist air.