STUDIES ON ORGANOLANTHANOID COMPLEXES .51. SYNTHESES OF BIS(2-METHOXYETHYLCYCLOPENTADIENYL) 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 equ ivalents of 2-methoxyethylcyclopentadienyl potassium salt in tetrahydr ofuran afford bis(2-methoxyethylcyclopentadienyl) lanthanoid iodide co mplex Cp2'YbI (I) (Cp'= MeOCH2CH2C5H4), tris(2-methoxyethylcyclopentad ienyl) lanthanoid complexes Cp3'Sm (II) and Cp3'Yb (III), respectively . The compound Cp2YbI (1) crystallizes from THF/hexane in orthorhombic space group P2(1)2(1)2(1) with cell dimensions a = 10.892(2), b = 12. 278(3), c = 12.805(5) angstrom, V = 1712.4 angstrom3 and D(calcd) = 2. 118 g cm-3 for Z = 4. The central metal Yb is coordinated by two Cp' r ing centroids, one iodine atom and two oxygen atoms of Cp' forming a d istorted trigonal bipyramid. The crystal of Cp3'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) angstrom, beta = 90.34(3), V = 2223.2 angstr om3, D(calcd) = 1.562 g cm-3 and Z = 4. The three Cp' ring centroids a nd two oxygen atoms of Cp' describe a trigonal bipyramid around the ce ntral ion of samarium. Complexes I, II and III are all unsolvated mono meric molecules with higher coordination number.