具有三个阴离子碳环的 +2 价稀土金属离子的分离：镧和铈的双金属双（环戊二烯基）还原芳烃配合物是四电子还原剂。

Isolation of +2 rare earth metal ions with three anionic carbocyclic rings: bimetallic bis(cyclopentadienyl) reduced arene complexes of La and Ce are four electron reductants.

作者信息

Kotyk Christopher M, Fieser Megan E, Palumbo Chad T, Ziller Joseph W, Darago Lucy E, Long Jeffrey R, Furche Filipp, Evans William J

机构信息

Department of Chemistry , University of California , Irvine , California 92697 , USA . Email:

Department of Chemistry , University of California , Berkeley , California 94720 , USA . Email:

出版信息

Chem Sci. 2015 Dec 1;6(12):7267-7273. doi: 10.1039/c5sc02486b. Epub 2015 Sep 21.

A new option for stabilizing unusual Ln ions has been identified in the reaction of Cp'Ln, (Ln = La, Ce; Cp' = CHSiMe), with potassium graphite (KC) in benzene in the presence of 2.2.2-cryptand. This generates [K(2.2.2-cryptand)][(Cp'Ln)(μ-η:η-CH)], , complexes that contain La and Ce in the formal +2 oxidation state. These complexes expand the range of coordination environments known for these ions beyond the previously established examples, (Cp''Ln) and (Cp'Ln) (Cp'' = CH(SiMe)-1,3), and generalize the viability of using three anionic carbocyclic rings to stabilize highly reactive Ln ions. In , a non-planar bridging (CH) ligand shared between two metals takes the place of a cyclopentadienyl ligand in (Cp'Ln). The intensely colored ( = ∼8000 M cm) complexes react as four electron reductants with two equiv. of naphthalene to produce two equiv. of the reduced naphthalenide complex, [K(2.2.2-cryptand)][Cp'Ln(η-CH)].

在2.2.2-穴醚存在下，Cp'Ln（Ln = La、Ce；Cp' = CHSiMe）与苯中的石墨钾（KC）反应，确定了一种稳定异常镧系离子的新方法。这生成了[K(2.2.2-穴醚)][(Cp'Ln)(μ-η:η-CH)]，即含有处于形式 +2 氧化态的La和Ce的配合物。这些配合物将这些离子已知的配位环境范围扩展到先前已确立的例子（Cp''Ln）和（Cp'Ln）（Cp'' = CH(SiMe)-1,3）之外，并推广了使用三个阴离子碳环来稳定高反应性镧系离子的可行性。在中，两个金属之间共享的非平面桥连（CH）配体取代了（Cp'Ln）中的环戊二烯基配体。颜色强烈的（ = ∼8000 M cm）配合物作为四电子还原剂与两当量的萘反应，生成两当量的还原萘化物配合物[K(2.2.2-穴醚)][Cp'Ln(η-CH)]。