How to Stabilize η3-Silapropargyl/Alkynylsilyl Complex of [CpL2M]+(L = CO, PMe3, or PF3 and M = W or Mo): Theoretical Predicti

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• 作者：Mausumi Ray ; Yoshihide Nakao ; Hirofumi Sato ; Hiroyuki Sakaba ; Shigeyoshi Sakaki
• 刊名：Organometallics
• 出版年：2009
• 出版时间：January 12, 2009
• 年：2009
• 卷：28
• 期：1
• 页码：65-73
• 全文大小：451K
• 年卷期：v.28,no.1(January 12, 2009)
• ISSN：1520-6041

文摘

We theoretically investigated here how to stabilize a new transition metal η³-silapropargyl/alkynylsilyl complex CpL₂M(η³-R²₂SiCCR¹) (M = W or Mo; L = CO, PMe₃, or PF₃; Cp = C₅H₅; R¹ = H, Me, ^tBu, or CF₃; R² = H, Me, or F) which is an interesting silicon analogue of a transition metal η³-propargyl complex. Though this complex was experimentally proposed as an intermediate in the synthesis of a tungsten acetylide−silylene complex Cp(CO)₂W(CC^tBu)(SiPh₂), it has not been synthesized yet. From theoretical computations with DFT method, we wish to propose that the combination of electron-withdrawing CF₃ on C, σ-electron-withdrawing/π-electron-donating F on Si, Mo center, and CO is the best to stabilize the η³-silapropargyl/alkynylsilyl form. However, the combination of bulky ^tBu on C, either H or Me on Si, W center, and PMe₃ is the best to stabilize the acetylide−silylene form, which is also an interesting species. The reasons are discussed herein.