A kinetic investigation of the oxidative addition reactions of the dimeric Bu4N[Ir2(μ-Dcbp)(CO)2(PCy3)2] complex with iodomethane
作者:Ebeth Grobbelaar、Jeanet Conradie、Johan A. Venter、Walter Purcell、T.T. Chiweshe
DOI:10.1016/j.jorganchem.2010.10.049
日期:2011.5
UV/visible kinetic results of the oxidative addition of iodomethane to Bu4N[Ir2(μ-Dcbp)(CO)2(PCy3)2] (Dcbp = 3,5-dicarboxylatepyrazolate anion) showed three time separable reactions. The first, very fast reaction corresponds to the a Ir(I)–Ir(III) alkyl species formation within 10−3 s. The second, relative fast reaction corresponds to Ir(III)–Ir(III) alkyl formation with a rate constant of 3.25(4) × 10−2 M−1 s−1
碘甲烷氧化成Bu 4 N [Ir 2(μ-Dcbp)(CO)2(PCy 3)2 ](Dcbp = 3,5-二羧酸吡唑并吡喃根阴离子)的红外和可见光动力学结果。可分离的反应。第一个非常快速的反应对应于在10 -3 s内形成一个Ir(I)-Ir(III)烷基物质;第二个相对快速的反应对应于一个速率下的Ir(III)-Ir(III)烷基形成常数为3.25(4)×10 -2 M -1 s -1,而第三次也是最慢的反应对应于Ir(III)–Ir(III)酰基的形成,速率常数为1.42×10 -5 s -1。红外数据清楚地表明,在形成Ir(I)-Ir(III)烷基产物时,存在许多平衡,然后生成反应生成Ir(III)-Ir(III),然后缓慢生成Ir(III)-Ir(III)。 Ir(III)-Ir(III)酰基产物。溶剂研究表明,在极性溶剂存在下,氧化加成活性增加,这表明极性过渡态。Ir(III)-Ir(III)烷基形成步骤(k