Stable Mononuclear Organometallic Pd(III) Complexes and Their C-C Bond Formation Reactivity
Stable Mononuclear Organometallic Pd(III) Complexes and Their C-C Bond Formation Reactivity
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DOI：
10.1021/ja103001g
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发表时间：
2010-06-02
影响因子：
15
通讯作者：
Mirica, Liviu M.
中科院分区：
文献类型：
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作者：
Khusnutdinova, Julia R.;Rath, Nigam P.;Mirica, Liviu M.
有机钯（III）配合物作为中间体参与了许多催化和化学计量转化。虽然一些双核有机金属Pd（III）配合物已被表征，但迄今为止尚未分离出单核有机金属Pd（III）配合物。本文报道了一系列由四齿配体N，N '-二叔丁基-2，11-二氮杂[3.3]（2，6）吡啶并[4，6]萘（N4）负载的Pd（III）配合物的合成和表征。Pd（II）络合物（N4）Pd-II（R）（X）（R = Me，X = Cl：1; R = Ph，X = Cl：2; R = X = Me：3）的化学或电化学氧化生成[（N4）（PdMeCl）-Me-III]（+）（1（+））、[（N4）（PdPhCl）-Ph-III]（+）（2（+））和[（N4）（PdMe 2）-Me-III]（+）（3（+））。这些稳定的Pd（III）配合物被分离并通过X-射线衍射、循环伏安法、UV-vis、EPR、磁矩测量和DFT表征，以确认顺磁性d（7）Pd（III）中心的存在。此外，这些Pd（III）配合物进行光诱导的C-C键的形成，得到相应的homocoupled产品乙烷或联苯。特别值得注意的是首次观察到从单甲基Pd络合物形成乙烷。
Organometallic Pd(III) complexes have been implicated as intermediates in a number of catalytic and stoichiometric transformations. While a few dinuclear organometallic Pd(III) complexes have been characterized, no mononuclear organometallic Pd(III) complexes have been isolated to date. Reported herein is the synthesis and characterization of a series of Pd(III) complexes supported by the tetradentate ligand N,N'-di-tert-butyl-2,11-diaza[3.3](2,6)pyridinophane (N4). Chemical or electrochemical oxidation of the Pd(II) complexes (N4)Pd-II(R)(X) (R = Me, X = Cl: 1; R = Ph, X = Cl: 2; R = X = Me: 3) generates [(N4)(PdMeCl)-Me-III](+) (1(+)), [(N4)(PdPhCl)-Ph-III](+) (2(+)), and [(N4)(PdMe2)-Me-III](+) (3(+)). These stable Pd(III) complexes were isolated and characterized by X-ray diffraction, cyclic voltammetry, UV-vis, EPR, magnetic moment measurements, and DFT to confirm the presence of paramagnetic d(7) Pd(III) centers. Moreover, these Pd(III) complexes undergo light-induced C-C bond formation to give the corresponding homocoupled products ethane or biphenyl. Particularly remarkable is the observation for the first time of ethane formation from monomethyl Pd complexes.