Muraoka Takako, Ishita Taichi, Kawachi Kosuke, Nishio Takuya, Ishihara Hiroto, Ueno Keiji
Division of Molecular Science, Graduate School of Science and Technology, Gunma University, Kiryu 376-8515, Japan.
Division of Pure and Applied Science, Graduate School of Science and Technology, Gunma University, Kiryu 376-8515, Japan.
Dalton Trans. 2024 Apr 23;53(16):7105-7114. doi: 10.1039/d4dt00631c.
Silanones (OSiR), a heavier congener of ketones (RCO), are highly reactive species that are readily converted to oligomeric siloxane (O-SiR). Coordination of silanones to the transition-metal fragments to afford silanone-coordinated complexes is a reliable silanone stabilization method. Recently, our group reported the synthesis, structures, and reactivity of dimesityl-substituted silanone complexes Cp*(OC)M{OSiMes(L)}(SiMe) (M = W, Mo, L: Lewis base, Cp*: η-CMe, Mes: 2,4,6-MeCH). Herein, to investigate the effect of substituents on the silicon atom during the formation of a silanone complex, we demonstrated the use of Mes and smaller Me groups. As a result, the formation of Mes(Me)-substituted silanone molybdenum complex Cp*(OC)Mo{OSiMes(Me)(py)}(SiMe) (5b, py: pyridine) was suggested, the silanone tungsten complex Cp*(OC)W{OSiMes(Me)(DMAP)}(SiMe) (4a, DMAP: 4-(dimethylamino)pyridine) was obtained, and a dimethyl-substituted disiloxanyloxy(dioxo) complex Cp*(O)W(OSiMeOSiMe) (9) was formed. The reaction of 4a with PMe proceeded the elimination of DMAP and migration of the SiMe group to the oxygen atom of the silanone ligand to afford Cp*(OC)W(SiMes(Me)OSiMe)(PMe) (11a). The Mo complex Cp*(OC)Mo(SiMes(Me)OSiMe)(PMe) (11b) was produced by the reaction of Cp*(OC)Mo{SiMes(Me)}(SiMe) (7b) with pyridine--oxide in the presence of PMe.
硅酮（OSiR）是酮（RCO）的较重同系物，是极易转化为低聚硅氧烷（O-SiR）的高反应活性物种。硅酮与过渡金属片段配位以提供硅酮配位络合物是一种可靠的硅酮稳定化方法。最近，我们小组报道了二甲基取代硅酮络合物Cp*(OC)M{OSiMes(L)}(SiMe)（M = W、Mo，L：路易斯碱，Cp*：η-CMe，Mes：2,4,6-MeCH）的合成、结构和反应活性。在此，为了研究硅酮络合物形成过程中硅原子上取代基的影响，我们展示了Mes和较小的Me基团的用途。结果表明形成了Mes(Me)取代的硅酮钼络合物Cp*(OC)Mo{OSiMes(Me)(py)}(SiMe)（5b，py：吡啶），得到了硅酮钨络合物Cp*(OC)W{OSiMes(Me)(DMAP)}(SiMe)（4a，DMAP：4-(二甲基氨基)吡啶），并形成了二甲基取代的二硅氧烷基氧基（二氧代）络合物Cp*(O)W(OSiMeOSiMe)（9）。4a与PMe的反应导致DMAP消除以及SiMe基团迁移至硅酮配体的氧原子上，从而得到Cp*(OC)W(SiMes(Me)OSiMe)(PMe)（11a）。通过在PMe存在下使Cp*(OC)Mo{SiMes(Me)}(SiMe)（7b）与吡啶 - 氧化物反应制备了Mo络合物Cp*(OC)Mo(SiMes(Me)OSiMe)(PMe)（11b）。
