When Metathesis Reactions Go Wrong: Novel Structural Consequences

The complex [Yb(Ph 2 pz) 3 (LiOBu)] 2 ( 1 ) (Ph 2 pz = 3,5‐diphenylpyrazolate), fortuitously obtained from reaction of Yb metal with a lithium containing sample of [SnMe 3 (Ph 2 pz)] at elevated temperatures forms a centrosymmetric butoxy‐ and pyrazolate‐bridged open box structure. Each ytterbium atom is eight coordinate with one chelating Ph 2 pz ligand, one μ‐η 2 :η 2 bridging pyrazolate, one μ‐η 2 (Yb):η 4 (Li) Ph 2 pz group and two bridging butoxide ligands. Each lithium atom is unsymmetrically chelated by an η 2 ‐Ph 2 pz group, η 4 (N,C(pz)C 2 (Ph)) bonded by another pyazolate group, and bridged through a butoxide oxygen atom to two ytterbium atoms. The type of η 4 ‐pyrazolate coordination is unprecedented and is the first observation of interactions to a metal by the Ph rings of the Ph 2 pz ligand. The complex [Li(dme) 3 ][Eu(Ph 2 pz) 3 (dme)] ( 2 ) obtained from reaction of Eu metal with the same sample of [SnMe 3 (Ph 2 pz)] in dme at room temperature is a charged separated species with the first anionic pyrazolatolanthanoidate(II) complex in which europium is eight coordinate with three chelating Ph 2 pz ligands and a chelating dme.