Zur Insertion in die Lanthanoid–Kohlenstoffbindung Synthese und Struktur von [CpSm(C6H5CH2NNO)]2 und [K(18-Krone-6)CpYb(NCS)2]∞

On the Insertion into the Lanthanide–Carbon Bond. Synthesis and Structure of [Cp Sm(C₆H₅CH₂NNO)]₂ and [K(18-crown-6)Cp Yb(NCS)₂]_∞ The compound [CpSm(CH₂C₆H₅)(thf)] was investigated, regarding its reactions with small molecules. The main subject was to detect an insertion into the Ln–C bond. With N₂O an insertion reaction is observed, yielding the dimer [CpSm(C₆H₅CH₂NNO)]₂ ( 1 ). The structural data of 1 was collected by a single crystal X-Ray diffraction analysis. (Space group P 1, Z = 1, a = 982.8(2) pm, b = 1052.2(2) pm, c = 1383.8(3) pm, α = 89.29(3)°, β = 73.64(3)°, γ = 66.41(3)°). In the dimer, the two Samarium ions are linked via an (η¹ : η²) bridge by two benzyl diazotato ligands. A nearly planar six-membered central Sm₂N₂O₂-ring is formend. Two pentamethylcyclopentadienyl ligands complete the coordination sphere of each Samarium ion, which are thus surrounded by four ligands each and have a distorted tetrahedral coordination geometry. An insertion of a SCN^– fragment in the Ln–C bond could not be observed. The substitution of the benzyl ligand leads to a polymeric chain structure. The new compound [K(18-crown-6)CpYb(NCS)₂]_∞ 2 contains a tetrahedrally coordinated Yb(III)-ion. (Space group P2₁/n}, Z = 4, a = 1640.6(3) pm, b = 1482.2(3) pm, c = 1674.5(3) pm, β = 102.82(1)°).