Synthesis and characterization of polynuclear half-sandwich lanthanoid complexes [Na(THF)6]2[Cpt6Sm6Se13] and [Li(THF)4]2[Cp6Nd6Se13]

The half-sandwich tert-butyl cyclopentadienyl lanthanoid complexes {[CptLn(THF)]2(μ2-Cl)2(μ3-Cl)3Na(THF)}n [Cpt=η5-tBuC5H4; Ln=Nd (1a), Sm (1b), Gd (1c), Yb (1d)] are prepared by the reaction of anhydrous lanthanoid trichloride, LnCl3, with NaCpt in THF solution. Complex 1b reacts with Na2Se5 to give hexanuclear samarium polyselenide complexes [Na(THF)6]2[Cpt6Sm6(μ6-Se)(μ-Se2)6] (2). An analogous cyclopentadienyl neodymium polyselenide complex [Li(THF)4]2[Cp6Nd6(μ6-Se)(μ-Se2)6] (3) is synthesized by the reaction of [CpNdCl2·2LiCl·5THF] with Na2Se5 in THF solution. The molecular structures of 1a and 2 were determined by X-ray crystal structure analysis. Complex 2 contains an interstitial selenium atom which is coordinated with six samarium atoms.