The new Ln-C σ-bond complexes bis(2-methoxyethylcyclopentadienyl) alkynyl lanthanum and ytterbium have been synthesized respectively by the displacing reaction of bis(2-methoxyethylcyclopentadienyl) lanthanide chlorides (Ln=La, Yb) with sodium alkynyl in THF at -20℃ with 77% and 66% yields. The new Ln-N σ-bond complexes (2-methoxyethylcyclopentadienyl) bis(bis-trimethylsilyl amido) ytterbium or yttrium were directly prepared by the one-pot reaction of sodium 2-methoxyethylcyclopentadienyl, lithium bis-trimethylsilyl amido and ytterbium or yttrium trichlorides at 0-5℃ with 56% and 72% yields, respectively. These complexes have been characterized by elemental analysis, IR, MS, and ^1H NMR spectra. They may be neutral and unsolvated monomers with the intramolecular coordination bonds between lanthanide metal and ligand oxygen atoms.

Key words: INFRARED SPECTROPHOTOMETRY, ELEMENTAL ANALYSIS, MASS SPECTROGRAPHY, CYCLOPENTADIENE P, LANTHANIDE SERIES METALS, YTTRIUM CHLORIDE, LANTHANUM CHLORIDE, YTTERBIUM CHLORIDE