Studies on organolanthanoid complexes: LI. Syntheses of bis- and tris(2-methoxyethylcyclopentadienyl) lanthanoid complexes and crystal structures of bis(2-methoxyethylcyclopentadienyl)ytterbium iodide and tris(2-methoxyethylcyclopentadienyl)samarium

Reactions of lanthanoid triiodides (Ln = Sm, Yb) with two or three equivalents of 2-methoxyethylcyclopentadienyl potassium salt in tetrahydrofuran afford bis(2-methoxyethylcyclopentadienyl) lanthanoid iodide complex Cp 2′YbI ( I) (Cp′ = MeOCH 2CH 2C 5H 4), tris(2-methoxyethylcyclopentadienyl) lanthanoid complexes Cp 3′Sm ( II) and Cp 3′Yb ( III), respectively. The compound Cp 2′YbI ( I) crystallizes from THF/hexane in orthorhombic space group P2 12 12 1 with cell dimensions a = 10.892(2), b = 12.278(3), c = 12.805(5) Å, V = 1712.4 Å 3 and D calcd = 2.118 g cm −3 for Z = 4. The central metal Yb is coordinated by two Cp′ ring centroids, one iodine atom and two oxygen atoms of Cp′ forming a distorted trigonal bipyramid. The crystal of Cp 3′Sm ( II) belongs to the monoclinic crystal system, space group P2 1/ n with a = 8.415(7), b = 20.439(3), c = 12.926(2) Å, β = 90.34(3)°, V = 2223.2 Å 3, D calcd = 1.562 g cm −3 and Z = 4. The three Cp′ ring centroids and two oxygen atoms of Cp′ describe a trigonal bipyramid around the central ion of samarium. Complexes I, II and III are all unsolvated monomeric molecules with higher coordination number.