710946-85-3Relevant academic research and scientific papers
The course of (R2R′SiO)3TaCl2 (R = tBu, R′ = H, Me, Ph, tBu (silox); R = iPr, R′ = tBu, iPr) reduction is dependent on siloxide size
Chadeayne, Andrew R.,Wolczanski, Peter T.,Lobkovsky, Emil B.
, p. 3421 - 3432 (2008/10/09)
Various sized siloxides (Cy3SiO > tBu 3SiO > tBu2PhSiO > tBu 2MeSiO ～ iPr2tBusiO > iPr3SiO > tBu2HSiO) were used to make (R2R′SiO)3TaCl2 (R = tBu, R′ = H (1-H), Me (1-Me), Ph (1-Ph), tBu (1); R = iPr, R′ = tBu (1-iPr2); R = R′ = iPr (1-iPr3); R = R′ = cHex (Cy)). Product analyses of sodium amalgam reductions of several dichlorides suggest that [(R2R′SiO)3Ta] 2(μ-Cl)2 may be a common intermediate. When the siloxide is large (1-tBu), formation of the Ta(III) species ( tBu3SiO)3Ta (6) occurs via disproportionation. When the siloxide is small, the Ta(IV) intermediate is stable (e.g., [( iPr3SiO)3Ta]2(μ-Cl)2 (2)), and when intermediate sized siloxides are used, solvent bond activation via unstable Ta(III) tris-siloxides is proposed to occur. Under hydrogen, reductions of 1-Me and 1-Ph provide Ta(IV) and Ta(V) hydrides [( tBu2MeSiO)3Ta]2(μ-H)2 (4-Me) and (tBu2PhSiO)3TaH2 (7-Ph), respectively.
