AlCp* as a directing ligand: C--H and Si--H bond activation at the reactive intermediate [Ni(AlCp*)(3)].
AlCp* as a directing ligand: C--H and Si--H bond activation at the reactive intermediate [Ni(AlCp*)(3)].
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DOI：
10.1002/anie.200353114
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发表时间：
2004-04
影响因子：
--
通讯作者：
T. Steinke;C. Gemel;M. Cokoja;M. Winter;R. Fischer
中科院分区：
文献类型：
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作者：
T. Steinke;C. Gemel;M. Cokoja;M. Winter;R. Fischer
类胡萝卜素化合物 ER（E= Al、Ga、In；R= Cp*、C (SiMe3) 3 等。 Cp*= C5Me5),[1] 由 Schnˆckel、Uhl、Roesky 和 Jutzi 团队于十年前首创，被认为是配位化学中有效但奇异的配体。 [2]它们与过渡金属中心的键合类似于等瓣配体 CO 或 PR3。 [3]同配簇 [Pt2 (GaCp*) 5][4] 和 [Pd3 (InCp*) 8][5] 的分离或 [(p-cymene) Ru (GaCp*) 3Cl2] 或 [Cp* Ru (ER) 3Cl](E= Ga, In, R= Cp*, C (SiMe3) 3)[6] 和 [Cp* Rh (InR) 3 (Cl) 2](R= Cp*, C (SiMe3) 3)[7] 表明这些化合物具有不同的反应性。尽管CO和膦被广泛用作有机金属化学中反应性和选择性的支持和引导配体，但ER配体的相应潜力尚未被描述。 [8]配合物中的配位键 M¿ E 具有相对强的极性，因为 E= Al、Ga 相对较强，并且 [3] ER 配体的空间需求相当大。 [9]因此，在[Ma (ER) b]型配合物的中心金属处不太可能发生解离反应或缔合反应。因此，此类化合物的有机金属化学似乎相当无望。事实上，[Ni (AlCp*) 4](1) 很容易通过 [Ni (cod) 2](COD= 环辛二烯) 与四当量的 AlCp* 在己烷中反应获得，结果证明它要么完全惰性（例如与 PPh3、CO、烯烃、炔烃），要么导致非特异性分解（例如与 I2、CH2Cl2），这与其经典类似物的高反应活性形成鲜明对比 [Ni (AlCp*) 4](1)。 (CO)4]和[Ni(PR3)4]。与这些早期结果相反，我们实验室的一个偶然观察表明这些化合物具有非常有前途的有机金属化学性质。
The carbenoid compounds ER (E= Al, Ga, In; R= Cp*, C (SiMe3) 3, etc. Cp*= C5Me5),[1] pioneered by the groups of Schnˆckel, Uhl, Roesky, and Jutzi ten years ago, are considered as potent, yet exotic ligands in coordination chemistry.[2] Their bonding to transition-metal centers is similar to that of the isolobal ligands CO or PR3.[3] The isolation of the homoleptic clusters [Pt2 (GaCp*) 5][4] and [Pd3 (InCp*) 8][5] or the remarkable fluxionality of cage compounds of the type [(p-cymene) Ru (GaCp*) 3Cl2] or [Cp* Ru (ER) 3Cl](E= Ga, In, R= Cp*, C (SiMe3) 3)[6] and [Cp* Rh (InR) 3 (Cl) 2](R= Cp*, C (SiMe3) 3)[7] suggests that these compounds have a diverse reactivity. Whereas CO and phosphanes are widely used as supporting and directing ligands for reactivity and selectivity in organometallic chemistry, a corresponding potential of the ER ligands has not yet been described.[8] The coordinative bond M¿ E in complexes is comparatively polar, for E= Al, Ga relatively strong and [3] the steric demand of the ER ligands is rather large.[9] Thus neither dissociative nor associative reactions are very likely to occur at the central metal in complexes of the type [Ma (ER) b]. Hence, a organometallic chemistry of such compounds appears to be rather hopeless. Indeed,[Ni (AlCp*) 4](1), which is easily available by the reaction of [Ni (cod) 2](COD= cyclooctadiene) with four equivalents of AlCp* in hexane, turns out to be either completely inert (eg with PPh3, CO, alkenes, alkynes) or leads to unspecific decomposition (eg with I2, CH2Cl2), in marked contrast to the high reactivity of its classic analogs [Ni (CO) 4] and [Ni (PR3) 4]. Contrary to these earlier results, a fortuitous observation has been made in our laboratory which suggests that these compounds have a very promising organometallic chemistry.