Expanding Divalent Organolanthanide Chemistry: The First Organothulium(II) Complex and the In Situ Organodysprosium(II) Reduction of Dinitrogen We thank the US National Science Foundation for support of this research.

The right choice of solvents, ligand (C5H3 (SiMe3) 2−), and reaction conditions has facilitated the isolation and structural characterization of the first TmII metallocene (see picture). In situ organometallic chemistry of the even more reducing DyII ion, namely a dinitrogen reduction to give the DyIII dinitrogen complex [C5H3 (SiMe3) 22Dy2N2], reveals the importance of carrying out such reactions in an atmosphere more inert than nitrogen.