Mechanochemical Synthesis of [1,3-(SiMe3)2C3H3]3(Al,Sc), a Base-Free Tris(allyl)aluminum Complex and Its Scandium Analogue
Mechanochemical Synthesis of [1,3-(SiMe3)2C3H3]3(Al,Sc), a Base-Free Tris(allyl)aluminum Complex and Its Scandium Analogue
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无碱三(烯丙基)铝配合物[1,3-(SiMe3)2C3H3]3(Al,Sc)及其钪类似物的机械化学合成
DOI：
10.1021/om5009204
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发表时间：
2014
期刊：
影响因子：
2.8
通讯作者：
A. Rheingold
中科院分区：
文献类型：
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作者：
Nicholas R. Rightmire;T. Hanusa;A. Rheingold
非溶剂化的三(烯丙基)铝，(C3H5)3Al，虽然已知与THF、OPPh3和吡啶的加合物，但从未被分离出来。由卤化铝和K[A‘]在醚中反应得到的体积较大的1，3-二(三甲基硅基)烯丙基阴离子(A’)或通过用R3Al(R=Me，Et)去质子化HA‘来制备无碱衍生物的尝试都不成功。然而，在固体状态下研磨AlX3和K[A‘]，然后用正己烷萃取混合物，可以高产率地生产A’3Al。单晶X射线结构表明，该单体分子含有σ键合的烯丙基配体(平均Al-C 1.964(3)A)，并且与已知的镓类似物一样，在溶液中是流动的。对母体(C3H5)3Al的密度泛函研究表明，(η1-C3H5)2(η3-C3H5)Al是具有混合构象的，尽管三甲基硅化配体明显阻止了A‘3Al的这种构象。A‘3Al立即与己烷中的二苯甲酮反应生成Al(OCPh2a’)3，但与体积较大的醇HOCPh3反应很小。磨..。
Unsolvated tris(allyl)aluminum, (C3H5)3Al, has never been isolated, although adducts with THF, OPPh3, and pyridine are known. Attempts to make a base-free derivative with the bulky 1,3-bis(trimethylsilyl)allyl anion (A′) from the reaction of aluminum halides and K[A′] in ethers or by deprotonation of HA′ with R3Al (R = Me, Et) were not successful. However, grinding AlX3 and K[A′] in the solid state, followed by extraction of the mixture with hexanes, produces A′3Al in high yield. A single-crystal X-ray structure demonstrated that the monomeric molecule contains σ-bonded allyl ligands (average Al–C 1.964(3) A) and, like the known gallium analogue, is fluxional in solution. A DFT study of the parent (C3H5)3Al indicates that the ligands would be of mixed hapticity, i.e., (η1-C3H5)2(η3-C3H5)Al, although the trimethylsilylated ligands evidently prevent that conformation in A′3Al. A′3Al reacts immediately with benzophenone in hexanes to produce Al(OCPh2A′)3 but negligibly with the bulky alcohol HOCPh3. Grinding...