Intermolecular 尾-Hydrogen Abstraction in Ytterbium, Calcium, and Potassium Tris(dimethylsilyl)methyl Compounds

详细信息    查看全文

• 作者：KaKing Yan ; George Schoendorff ; Brianna M. Upton ; Arkady Ellern ; Theresa L. Windus ; Aaron D. Sadow
• 刊名：Organometallics
• 出版年：2013
• 出版时间：March 11, 2013
• 年：2013
• 卷：32
• 期：5
• 页码：1300-1316
• 全文大小：916K
• 年卷期：v.32,no.5(March 11, 2013)
• ISSN：1520-6041

文摘

A series of organometallic compounds containing the tris(dimethylsilyl)methyl ligand are described. The potassium carbanions KC(SiHMe₂)₃ and {KC(SiHMe₂)₃TMEDA}₂ are synthesized by deprotonation of the hydrocarbon HC(SiHMe₂)₃ with potassium benzyl. {KC(SiHMe₂)₃TMEDA}₂ crystallizes as a dimer with two types of three-center鈥搕wo-electron K鈥揌鈥揝i interactions: side-on coordination of SiH (K鈥揌鈥揝i = 102(2)掳) and more obtuse K鈥揌鈥揝i structures (K鈥揌鈥揝i 鈮?150掳). The divalent calcium and ytterbium compounds M{C(SiHMe₂)₃}₂L (M = Ca, Yb; L = 2THF, TMEDA) are prepared from MI₂ and 2 equiv of KC(SiHMe₂)₃. Low ¹J_SiH coupling constants in the NMR spectra, low-energy 谓_SiH bands in the IR spectra, and short M鈥揝i distances and small M鈥揅鈥揝i angles in the crystal structures suggest 尾-agostic interactions on each C(SiHMe₂)₃ ligand. The IR assignments of M{C(SiHMe₂)₃}₂L (L = 2THF, TMEDA) are supported by DFT calculations. The compounds M{C(SiHMe₂)₃}₂L react with 1 or 2 equiv of B(C₆F₅)₃ to give the 1,3-disilacyclobutane {Me₂SiC(SiHMe₂)₂}₂ and MC(SiHMe₂)₃HB(C₆F₅)₃L or M{HB(C₆F₅)₃}₂L, respectively. In addition, M{C(SiHMe₂)₃}₂L compounds react with BPh₃ to give 尾-H abstracted products. The compounds M{C(SiHMe₂)₃}₂THF₂ react with SiMe₃I to yield Me₃SiH and disilacyclobutane as the products of 尾-H abstraction, while M{C(SiHMe₂)₃}₂TMEDA and Me₃SiI form a mixture of Me₃SiH and the alkylation product Me₃SiC(SiHMe₂)₃ in a 1:3 ratio.