Tuning the <i>π</i>-backbonding and <i>σ</i>-<i>trans</i> effect of N^C^N coordinated Pt(II) complexes. <i>Kinetic and computational study</i>
作者:Tshephiso R. Papo、Deogratius Jaganyi
DOI:10.1080/00958972.2014.1001752
日期:2015.3.4
results in an increase in the rate of substitution. Second-order kinetics and large negative activation entropies (ΔS#) support an associative substitution mechanism. The experimental data are supported by DFT calculations. The mechanistic pathway for the substitution reaction of a strong trans labilizing phenyl of N^C^N platinum(II) complexes by biorelevant thiourea nucleophiles go through the solvent associated
环金属化配合物的亲核取代反应;[PtL2Cl] (L2 = 3,5-二(2-吡啶基)-氟苯)、[PtL3Cl] (L3 = 2,4-二(2-吡啶基)-氟苯) 和 [PtL4Cl] (L4 = 3,5 -二(2-吡啶基)-甲苯) 与一系列具有不同空间性质的中性亲核试剂,硫脲 (TU)、N,N-二甲基硫脲 (DMTU) 和 N,N,N',N'-四甲基硫脲 (TMTU) ,在准一级条件下在离子强度为 0.1 M(0.09 M LiCF3SO3 和 0.01 M LiCl)的甲醇溶液中进行研究。使用紫外可见分光光度法和停流分光光度法研究氯配体的取代率作为亲核试剂浓度和温度的函数。观察到的取代反应的准一级速率常数服从速率定律 kobs = k2[Nu] + k−2。当 [PtL1Cl] 用作参考时,所研究配合物的反应性遵循以下顺序 [PtL2Cl] > [PtL3Cl] > [PtL4Cl] > [PtL1Cl]。氯基团的不稳定性取决于