Ring-Expanded N-Heterocyclic Carbene Complexes of Ruthenium
Ring-Expanded N-Heterocyclic Carbene Complexes of Ruthenium
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DOI：
10.1021/om901044u
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发表时间：
2010-02-22
期刊：
影响因子：
2.8
通讯作者：
Whittlesey, Michael K.
中科院分区：
文献类型：
--
作者：
Armstrong, Robert;Ecott, Christopher;Whittlesey, Michael K.
六元杂环卡宾1，3-双（2，4，6-三甲基苯基）-3，4，5，6-四氢嘧啶-2-亚基（6-Mes）与Ru（PPh 3）（3）（CO）HF反应，得到Ru（6-Mes）（PPh 3）（CO）HF（1），经Et 3SiH处理，生成五配位C-H活化的卡宾配合物Ru（6-Mes）（PPh 3）（CO）H（2）。氯化物前体Ru（PPh 3）（3）（CO）HCl得到产物与6-Mes的混合物，但与1，3-双（异丙基）-3，4，5，6-四氢嘧啶-2-亚基（6-Pr-1）干净地反应，得到六配位活化配合物Ru（6-Pr-1）（PPh 3）（2）（CO）H（3a），其中氢化物反式到活化NHC的亚甲基臂。该络合物在溶液中异构化，Δ H双匕首和AS双匕首值分别为98.2 +/- 4.6 kJ mol（-1）和15.5 +/- 14.5 J mol（-1）K-1。异构化的主要产物3b（其中氢化物配体反式为卡宾）可直接通过6-'Pr与Ru（PPh 3）（3）（CO）H-2反应制得。
The six-membered N-heterocyclic carbene 1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene (6-Mes) reacts with Ru(PPh3)(3)(CO)HF to afford Ru(6-Mes)(PPh3)(CO)HF (1), which is converted to the five-coordinate C-H activated carbene complex Ru(6-Mes)'(PPh3)(CO)H (2) upon treatment with Et3SiH. The hydride chloride precursor Ru(PPh3)(3)(CO)HCl affords a mixture of products with 6-Mes, but reacts cleanly with 1,3-bis(isopropyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene (6-Pr-i) to give the six-coordinate activated complex Ru(6-Pr-i)'(PPh3)(2)(CO)H (3a), in which the hydride is trans to the methylene arm of the activated NHC. This complex isomerizes in solution with Delta H double dagger and AS double dagger values of 98.2 +/- 4.6 kJ mol(-1) and 15.5 +/- 14.5 J mol(-1) K-1. The major product from the isomerization, 3b, in which the hydride ligand is trans to carbene, can be made directly by reaction of 6-'Pr with Ru(PPh3)(3)(CO)H-2.