Orientational Isomerism and Its Reactivity of a Main Group Sandwich Anion [Ge₉-In-Ge₉]^5-

Two isomers of a sandwich-type anion [Ge-9-In-Ge-9](5-) were synthesized by controlling the chelating agents (2,2,2-crypt/18-C-6). Further reactions with early/late transition metal complexes, Mo(CO)(6) and Ni(COD)(2), respectively, yielded two new types of inorganic sandwich derivatives: a half-sandwich cluster [Ge-9-In-Mo(CO)(5)](3-) with a low-valence In(I) center and an unsymmetrical sandwich-type cluster {[(Ni@Ge-9)In(Ni-0.648@Ge-9)]}(5-) due to the insertion of Ni atoms, respectively. The isolation of these new derivatives demonstrates the reactivity of sandwich-type [Ge-9-In-Ge-9](5-) acting as the precursor, which provides some enlightenment for constructing new inorganic sandwich compounds.