Reversible halide-modulated nickel-nickel bond cleavage: metal-metal bonds as design elements for molecular devices.
Reversible halide-modulated nickel-nickel bond cleavage: metal-metal bonds as design elements for molecular devices.
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DOI：
10.1002/anie.201102797
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发表时间：
2011-08-08
影响因子：
16.6
通讯作者：
Agapie, Theodor
中科院分区：
文献类型：
--
作者：
Chao, Steven T.;Lara, Nadia C.;Lin, Sibo;Day, Michael W.;Agapie, Theodor
基本分子器件的合成和研究是一个活跃的研究领域，旨在了解复杂分子机器的基本设计和功能参数在这种情况下，过渡金属与设计优雅的配体框架一起被广泛使用通常，过渡金属在这些框架中与不同的供体结合，引起大分子运动，作为pH变化的函数，[3]氧化还原过程，[4]被光激发，[5]加热，[5]引入额外的配体，[3]和去除或添加不同的金属离子本文报道了基于氯化物介导的Ni-Ni和热可及的Ni-P键裂解的策略，以构建铰链和机械曲柄机构的分子类似物。我们小组之前的一份报告表明，在将键合的共面NiI-NiI片段还原为非键合的跨面Ni0-Ni0物种时，对苯平台可以作为两种金属相对于彼此的旋转轴在这种情况下，化学反应是不可逆的；人们寻找一种能更好地用化学方法控制分子运动的物种。受相关的三芳基苯结构与吡啶和醇氧基给体支持强大的三核过渡金属配合物的能力的启发，我们开发了一种三膦变体，1,[8]将Ni (COD) 2 （COD= 1,5 -环二烯）和NiCl2 (dme)（dme= 1,2 -二甲氧基乙烷）的一个等价物分别加入到1中生成深棕色物质2（图1a）。对2的单晶x射线衍射（XRD）研究揭示了镍的双核配合物（图2）。一个金属中心配位两个膦和一个氯，并与中心芳烃的一个碳（C18）相互作用(（Ni1-C18)= 2.047 (2) Å）。值得注意的是，C18离中心环上另外五个碳原子的平面约为18。第二个镍中心位于中心环的对面，并与中心环的π系结合一个膦、一个氯化物。两个镍中心在中心环的相对表面上的结合与相关的对三苯基和2 ',3 ' -二氢对三苯基二膦二镍体系形成对比，其中二氯化二镍部分与中心环共结合。[7,9]对于化合物2，类似的结合模式会导致更高的金属配位数，可能导致氯和膦配体之间的空间排斥。
The synthesis and study of basic molecular devices are active areas of research aimed toward understanding the fundamental design and functional parameters required for the construction of complex molecular machines.[1] Transition metals have been used extensively in this context in conjunction with elegantly designed ligand frameworks.[2] Typically, transition metals bind to different sets of donors in these frameworks, inducing large molecular motions, as a function of changes in pH,[3] redox processes,[4] excitation by light,[5] heating,[5] introduction of additional ligands,[3] and removal or addition of different metal ions.[6] We report herein strategies based on chloride-mediated Ni-Ni and thermally accessible Ni-P bond cleavage to construct molecular analogues of hinge and mechanical crank mechanisms.A previous report from our group shows that a p-terphenyl platform can act as an axis for rotation of two metals with respect to each other upon reduction of a bonded cofacial NiI-NiI moiety to a non-bonded transfacial Ni0-Ni0 species.[7] In that context, the chemical reaction is irreversible; a species that allows better chemical control over molecular motion was sought. Inspired by the ability of related triarylbenzene architectures with pyridine and alkoxide donors to support robust trinuclear transition metal complexes, we developed a triphosphine variant, 1.[8] Addition of a single equivalent each of Ni (COD) 2 (COD= 1, 5-cyclooctadiene) and NiCl2 (dme)(dme= 1, 2-dimethoxyethane) to 1 generates a dark brown species, 2 (Figure 1a). A single crystal X-ray diffraction (XRD) study of 2 reveals a dinuclear complex of nickel (Figure 2). One metal center coordinates two phosphines and one chloride and interacts with one carbon (C18) of the central arene ((Ni1-C18)= 2.047 (2) Å). Notably, C18 comes out of the plane of the five other carbon atoms of the central ring by ca. 18. The second nickel center is located on the opposite face of the central ring and binds one phosphine, one chloride and the π system of the central ring. The binding of the two nickel centers on opposite faces of the central ring contrasts with the related p-terphenyl and 2’, 3’-dihydro-p-terphenyl diphosphine dinickel systems in which the dinickel dichloride moiety is cofacially bound by the central ring.[7, 9] For compound 2, a similar binding mode would lead to a higher metal coordination number, likely leading to steric repulsions between the chloride and phosphine ligands.
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DOI：
10.1002/anie.198306201
发表时间：
1983-01-01
期刊：
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION IN ENGLISH
影响因子：
--
作者：
JONAS, K;KOEPE, G;TSAY, YH
通讯作者：
TSAY, YH
影响因子：
2.8
作者：
Bai, GC;Wei, PR;Stephan, DW
通讯作者：
Stephan, DW
影响因子：
15
作者：
Hiraoka, Shuichi;Okuno, Erika;Shionoya, Mitsuhiko
通讯作者：
Shionoya, Mitsuhiko
影响因子：
15
作者：
Hiraoka, S;Shiro, M;Shionoya, M
通讯作者：
Shionoya, M
影响因子：
56.9
作者：
Fletcher, SP;Dumur, F;Feringa, BL
通讯作者：
Feringa, BL