Syntheses and Structures of the Crystalline, Highly Crowded 1,3-Bis(trimethylsilyl)cyclopentadienyls [MCp″3] (M = Y, Er, Yb), [PbCp″2], [{YCp″2(μ-OH)}2], [(ScCp″2)2(μ-η2:η2-C2H4)], [YbCp″2Cl(μ-Cl)K(18-crown-6)], and [{KCp″}∞]

Yttrium and the smaller group 3 and 4f metal homoleptic M­(III) cyclopentadienyls [MCp″3] (Cp″ = [η5-C5H3(SiMe3)2-1,3]− and M = Y (1Y), Er (1Er), or Yb (1Yb)) were prepared from YCp″2I (2Y) or the appropriate [LnCp″2I­(thf)] and KCp″ in satisfactory (1Y), very low (1Er), or low (1Yb) yield. Attempted reaction of [ScCp″2I­(thf)] with KCp″ failed to produce the homoleptic Sc­(III) cyclopentadienyl. Compound 1Yb was synthesized in better yield by the redox reaction between [YbCp″2(thf)] and either [PbCp″2] (3) or the in situ prepared HgCp″2 (4) analogue. Complexes 3 and 4 were obtained by a salt metathesis route, 3 was isolated as a crystalline solid, while 4 was used only as a hexane solution. The structures of crystalline 1Y, 1Yb, 3, [{YCp″2(μ-OH)}2] (5Y) [prepared by hydrolysis of 1Y], [(ScCp″2)2(μ-η2:η2-C2H4)] (6) {isolated in low yield from the reaction of ScCp″2I (2Sc) with [K­(18-crown-6)]2[C6H2(SiMe3)4-1,2,4,5]}, [LaCp″2Cl­(μ-Cl)­K­(18-crown-6)] (7La) {obtained from the foregoing potassium reagent and [{LaCp″2(μ-Cl)}2]}, [YbCp″2Cl­(μ-Cl)­K­(18-crown-6)] (7Yb), and [{KCp″}∞] (8) were determined by X-ray diffraction.

以YCp″₂I（2Y）或相应的[LnCp″₂I(四氢呋喃（tetrahydrofuran, thf）)]与KCp″为原料，成功制备了钇以及尺寸更小的第3族和4f系金属同配体M(III)环戊二烯配合物[MCp″₃]（其中Cp″为[η⁵-C₅H₃(三甲基硅基（trimethylsilyl, SiMe3）)₂-1,3]⁻，即η⁵-1,3-双(三甲基硅基)环戊二烯基阴离子，M分别为Y（1Y）、Er（1Er）或Yb（1Yb)），其中1Y的产率良好，1Er产率极低，1Yb产率较低。尝试使[ScCp″₂I(四氢呋喃（tetrahydrofuran, thf）)]与KCp″发生反应，未能得到同配体Sc(III)环戊二烯配合物。通过[YbCp″₂(四氢呋喃（tetrahydrofuran, thf）)]与[PbCp″₂]（3）或原位制备的HgCp″₂（4）类似物之间的氧化还原反应，可以以更高产率合成1Yb。配合物3和4通过盐复分解反应路线制备得到，3以结晶固体形式分离获得，而4仅以己烷溶液形式使用。通过X射线衍射确定了以下结晶配合物的结构：1Y、1Yb、3、[{YCp″₂(μ-OH)}₂]（5Y，由1Y水解制备得到）、[(ScCp″₂)₂(μ-η²:η²-C₂H₄)]（6，由ScCp″₂I（2Sc）与[K(18-冠-6（18-crown-6）)]₂[C₆H₂(三甲基硅基（trimethylsilyl, SiMe3）)₄-1,2,4,5]反应，以低产率分离得到）、[LaCp″₂Cl(μ-Cl)K(18-冠-6（18-crown-6）)]（7La，由前述钾试剂与[{LaCp″₂(μ-Cl)}₂]反应得到）、[YbCp″₂Cl(μ-Cl)K(18-冠-6（18-crown-6）)]（7Yb）以及[{KCp″}∞]（8）。