Metal-Ion Influence on Ligand-Centered Hydrogen-Atom Transfer
Metal-Ion Influence on Ligand-Centered Hydrogen-Atom Transfer
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DOI：
10.1021/acs.inorgchem.0c02981
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发表时间：
2021-01-12
影响因子：
4.6
通讯作者：
Heyduk, Alan F.
中科院分区：
文献类型：
--
作者：
Charette, Bronte J.;Ziller, Joseph W.;Heyduk, Alan F.
以配体为中心的氢原子转移（HAT）反应性进行了检查的家庭的第10族金属配合物含有三齿钳形配体衍生自双（2-巯基-对甲苯基）胺，[SNS]H-3。在不同的氧化还原和质子化状态下，用[SNS]配体平台合成了六种新的钯和铂的金属配合物，以完成先前报道的与镍的第10族系列。HAT反应性检查了这个家庭的镍，钯，铂络合物，以确定金属离子的配体为中心的反应性的影响。热力学测量结果表明，N-H键解离自由能沿着Ni < Pd < Pt系列增加约10 kcal mol（-1），这是由配体的氧化还原电位和pK（a）的变化驱动的。所有三种金属配合物的动力学分析表明，HAT反应性的障碍主要是熵，而不是这个系统的熵。
The ligand-centered hydrogen-atom-transfer (HAT) reactivity was examined for a family of group 10 metal complexes containing a tridentate pincer ligand derived from bis(2-mercapto-p-tolyl)amine, [SNS]H-3. Six new metal complexes of palladium and platinum were synthesized with the [SNS] ligand platform in different redox and protonation states to complete the group 10 series previously reported with nickel. The HAT reactivity was examined for this family of nickel, palladium, and platinum complexes to determine the impact of a metal ion on the ligand-centered reactivity. Thermodynamic measurements revealed that N-H bond dissociation free energies increased by approximately 10 kcal mol(-1) along the series Ni < Pd < Pt driven by changes to both the redox potential and pK(a) of the ligand. Kinetic analyses for all three metal complexes suggest that the barrier to the HAT reactivity is primarily entropic rather than enthalpic for this system.