Oligomeric rare-earth metal cluster complexes with endohedral transition metal atoms

• Rare-earth metal cluster complexes encapsulate transition metal atoms.
• Oligomers are built via connection of octahedral clusters via common edges or faces.
• Dimers through pentamers with closed structures are known.
• Tetramers including a tetrahedron of endohedral atoms are the most prolific.

Comproportionation reactions of rare-earth metal trihalides (RX3) with the respective rare-earth metals (R) and transition metals (T) led to the formation of 22 oligomeric R cluster halides encapsulating T, in 19 cases for the first time. The structures of these compounds were determined by single-crystal X-ray diffraction and are composed of trimers ({T3R11}X15-type, P63/m), tetramers ({T4R16}X28{R4} (P-43m), {T4R16}X20 (P42/nnm), {T4R16}X24(RX3)4 (I41/a) and {T4R16}X23 (C2/m) types of structure) and pentamers ({Ru5La14}2Br39, Cc) of {TRr}n (n=2–5) clusters. These oligomers are further enveloped by inner (Xi) as well as outer (Xa) halido ligands, which possess diverse functionalities and interconnect like oligomers through i–i, i–a and/or a–i bridges. The general features of the crystal structures for these new compounds are discussed and compared to literature entries as well as different structure types with oligomeric T centered R clusters. Dimers and tetramers originating from the aggregation of {TR6} octahedra via common edges are more frequent than trimers and pentamers, in which the {TRr} clusters share common faces.

Rare earth-metal cluster complexes with endohedral transition metal atoms {TR6} may connect via common edges or faces to form dimers, trimers, tetramers and pentamers of which the tetramers are the most prolific. Packing effects and electron counts play an important role.Figure optionsDownload as PowerPoint slide