Freitag Kerstin, Molon Mariusz, Jerabek Paul, Dilchert Katharina, Rösler Christoph, Seidel Rüdiger W, Gemel Christian, Frenking Gernot, Fischer Roland A
Inorganic and Metalorganic Chemistry , Technical University Munich , D-85748 , Garching , Germany . Email:
Inorganic Chemistry II - Organometallics & Materials , Ruhr-University Bochum , D-44780 , Bochum , Germany.
Chem Sci. 2016 Oct 1;7(10):6413-6421. doi: 10.1039/c6sc02106a. Epub 2016 Jun 23.
The analogy between ZnR fragments and the hydrogen radical represents a fruitful concept in organometallic synthesis. The organozinc(ii) and -zinc(i) sources ZnMe (Me = methyl) and [ZnCp*] (Cp* = pentamethylcyclopentadienyl) provide one-electron fragments ·ZnR (R = Me, Cp*), which can be trapped by transition metal complexes [L M], yielding [L (ZnR) ]. The addition of the dizinc compound [ZnCp*] to coordinatively unsaturated [L M] by the homolytic cleavage of the Zn-Zn bond can be compared to the classic oxidative addition reaction of H, forming dihydride complexes [L M(H)]. It has also been widely shown that dihydrogen coordinates under preservation of the H-H bond in the case of certain electronic properties of the transition metal fragment. The σ-aromatic triangular clusters [ZnCp*] and [ZnCuCp*] may be regarded as the first indication of this so far unknown, side-on coordination mode of [ZnCp*]. With this background in mind the question arises if a series of complexes featuring the ZnM structural motif can be prepared exhibiting a (more or less) intact Zn-Zn interaction, di-zinc complexes which are analogous to non-classical dihydrogen complexes of the Kubas type. In order to probe this idea, a series of interrelated organozinc nickel and palladium complexes and clusters were synthesized and characterized as model compounds: [Ni(ZnCp*)(ZnMe)(PMe)] (), [Ni(ZnCp*)(ZnMe)(PMe)] (), [{Ni(CN Bu)(μ-ZnCp*)(μ-ZnMe)}] (), [Pd(ZnCp*)(CN Bu)] () and [PdZn(PCy)(Cp*)] (). The dependence of Zn···Zn interactions as a function of the ligand environments and the metal centers was studied. Experimental X-ray crystallographic structural data and DFT calculations support the analogy between dihydrogen and dizinc transition metal complexes.
锌自由基片段与氢自由基之间的类比在有机金属合成中是一个富有成效的概念。有机锌（II）和锌（I）源ZnMe（Me = 甲基）和[ZnCp*]（Cp* = 五甲基环戊二烯基）提供单电子片段·ZnR（R = Me，Cp*），其可被过渡金属配合物[L M]捕获，生成[L (ZnR) ]。通过锌 - 锌键的均裂将二锌化合物[ZnCp*]添加到配位不饱和的[L M]中，可与H的经典氧化加成反应相比较，形成二氢配合物[L M(H)]。还广泛表明，在过渡金属片段具有某些电子性质的情况下，氢气在H - H键保持的情况下配位。σ-芳香族三角簇[ZnCp*]和[ZnCuCp*]可被视为这种迄今未知的[ZnCp*]侧基配位模式的首个迹象。考虑到这一背景，问题就出现了，是否可以制备一系列具有ZnM结构基序的配合物，它们表现出（或多或少）完整的锌 - 锌相互作用，即类似于库巴斯型非经典二氢配合物的二锌配合物。为了探究这一想法，合成并表征了一系列相互关联的有机锌镍和钯配合物及簇作为模型化合物：[Ni(ZnCp*)(ZnMe)(PMe)]（），[Ni(ZnCp*)(ZnMe)(PMe)]（），[{Ni(CN Bu)(μ-ZnCp*)(μ-ZnMe)}]（），[Pd(ZnCp*)(CN Bu)]（）和[PdZn(PCy)(Cp*)]（）。研究了锌···锌相互作用作为配体环境和金属中心函数的依赖性。实验X射线晶体学结构数据和密度泛函理论计算支持二氢和二锌过渡金属配合物之间的类比。
