A Density Functional Theory study of RE(COT)_n (RE: La-Lu; n=1-2) sandwich complexes

Rare-earth atoms and clusters, supported on organic molecules such as benzene (Bz) and Cyclooctatetraene (COT), provide an attractive pathway for developing novel nanostructures with unique magnetic and optical properties. In this project, we performed a Density Functional Theory (DFT) study of rare-earth (RE) atoms (RE = La-Lu) supported on the organic molecule cyclooctatetraene (COT, C₈H₈). We focused on the geometries, stability, electronic, and magnetic properties of RE(COT)_n (RE = La–Lu; n = 1-2) complexes.

Our calculations have shown that the interaction between the RE atom and the boat-shaped COT molecule has resulted in a stable RE(COT) complex, with the COT molecule becoming planar. In RE(COT)₂ complexes, the RE-atom was found to be intercalated between two planar COT molecules, thus forming a stable sandwich complex. The planarity of COT can be attributed to a significant charge transfer from the 6s orbital of the RE atom to the COT. The RE(COT)_n (RE = La–Lu; n = 1-2) complexes, except for Tb(COT)_n and Dy(COT)₂, have retained the spin magnetic moments of the bare RE atoms. We will also discuss the similarities and differences between RE(COT) and RE(Bz) complexes. Future research will focus on extending RE(COT)_n complexes to create magnetic nanowires.