Effect of ligand steric properties and halide identity on the mechanism for oxidative addition of haloarenes to trialkylphosphine Pd(0) complexes.
Effect of ligand steric properties and halide identity on the mechanism for oxidative addition of haloarenes to trialkylphosphine Pd(0) complexes.
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DOI：
10.1021/ja900798s
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发表时间：
2009-06-17
影响因子：
15
通讯作者：
Hartwig JF
中科院分区：
文献类型：
--
作者：
Barrios-Landeros F;Carrow BP;Hartwig JF
研究了PhX（X = I，Br，Cl）与Pd（PtBu 3）2（1），Pd（1-AdPtBu 2）2（2），Pd（CyPtBu 2）2（3），Pd（PCy 3）2（4）的氧化加成反应，以确定空间位阻性质对氧化加成产物配位数的影响，并确定卤化物的类型是否影响该产物的性质.动力学数据表明，膦配位的配合物，在氧化加成过程的不可逆步骤中反应的配合物1-4的数量取决于卤化物比配体的空间性质。在所有情况下，L2 Pd（0）都发生了PhI氧化加成的限速步骤，这是由kobs不依赖于[PtBu 3]、[1-AdPtBu 2]和[CyPtBu 2]以及当反应用Pd（PCy 3）3引发时速率常数对[PCy 3]的反向依赖性确定的。PhCl的氧化加成的不可逆步骤发生在每种情况下的单膦物种，作为信号的配体的浓度上的速率常数的逆依赖性。PhBr的氧化加成的不可逆步骤发生与双膦物种，作为信号的速率常数对膦的浓度的零级或小的依赖性。因此，反应性较低的氯代芳烃的加成通过较低配位的中间体发生，而不是反应性较高的卤代芳烃的加成。
The oxidative addition of PhX (X = I, Br, Cl) to the complexes Pd(PtBu3)2 (1), Pd(1-AdPtBu2)2 (2), Pd(CyPtBu2)2 (3), and Pd(PCy3)2 (4) were studied to determine the effect of steric properties on the coordination number of the species that undergoes oxidative addition and to determine if the type of halide affects the identity of this species. The kinetic data imply that the number of phosphines coordinated to the complex that reacts in the irreversible step of the oxidative addition processes for complexes 1-4 depends on the halide more than the steric properties of the ligands. The rate-limiting step of the oxidative addition of PhI occurred with L2Pd(0) in all cases, as determined by the lack of dependence of kobs on [PtBu3], [1-AdPtBu2], and [CyPtBu2] and the inverse dependence of the rate constant on [PCy3] when the reaction is initiated with Pd(PCy3)3. The irreversible step of the oxidative addition of PhCl occurred with a monophosphine species in each case, as signaled by an inverse dependence of the rate constant on the concentration of ligand. The irreversible step of the oxidative addition of PhBr occurred with a bisphosphine species, as signaled by the zeroth-order or small dependence of the rate constant on the concentration of phosphine. Thus, the additions of the less reactive chloroarenes occur through lower-coordinate intermediates than additions of the more reactive haloarenes.
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影响因子：
3.6
作者：
Hartwig, JF;Kawatsura, M;Alcazar-Roman, LM
通讯作者：
Alcazar-Roman, LM
影响因子：
15
作者：
Lewis, AKD;Caddick, S;Leonard, J
通讯作者：
Leonard, J
影响因子：
2.8
作者：
AMATORE, C;PFLUGER, F
通讯作者：
PFLUGER, F
影响因子：
15
作者：
Amatore, C;Broeker, G;Khalil, F
通讯作者：
Khalil, F
影响因子：
2.3
作者：
FAUVARQUE, JF;PFLUGER, F;TROUPEL, M
通讯作者：
TROUPEL, M