Kinetics and mechanism of the activation of molecular hydrogen by bis(dimethylglyoximato)cobalt(<scp>II</scp>) derivatives
作者:László I. Simándi、Éva Budó–Záhonyi、Zoltán Szeverényi、Sándor Németh
DOI:10.1039/dt9800000276
日期:——
The reaction of H2 with bis(dimethylglyoximato)cobalt(II), [Co(Hdmg)2], and its 1 : 1 pyridine (py) adduct yields 3-aminobutan-2-one oxime via hydrogenation of the co-ordinated Hdmg–. Excess of Hdmg– is hydrogenated catalytically. The initial rate of H2 uptake is first order with respect to H2 pressure and second order with respect to overall cobalt concentration. Axial co-ordination of py, NEt2H,
H 2与双(二甲基乙二酰肟基)钴(II),[Co(Hdmg)2 ]及其1:1吡啶(py)加合物的反应通过配位的Hdmg的加氢反应生成3-氨基丁烷-2-一肟–。过量的Hdmg –被催化氢化。相对于H 2压力,H 2吸收的初始速率为一阶,相对于总钴浓度而言,其初始阶跃为二阶。py,NEt 2 H和PPh 3的轴向配位提高了速率,五配位加合物比母体钴肟的反应性更高(II)。在20°C下,1:1和1:2 py加合物的分光光度稳定性常数分别为186和0.75 dm 3 mol –1。H 2吸收的速率确定步骤是两种氢化钴氧肟(III)的双分子反应。在没有py的情况下,在20°C下在MeOH和50%v / v甲醇-水中的总速率系数分别为3.1和9.4 dm 6 mol –2 s –1。对于包含py的1:1加合物的反应,相应的值为34.7和323 dm 6 mol –2 s –1, 分别。中间的氢化,包含